Great things from small things

Blog Archive

Filter by: Nanotechnology
Page 4


A Chinese Perspective

Before the dawn of the new millennium, the then President of the USA Bill Clinton was invited by Science magazine to write an editorial. In the one-page piece, Science in the 21st century, he wrote: “Imagine a new century, full of promise, molded by science, shaped by technology, powered by knowledge. We are now embarking on our most daring explorations, unraveling the mysteries of our inner world and charting new routes to the conquest of disease” [1]. In 2000, the US government firmly kicked off its significant and influential National Nanotechnology Initiative (NNI) program after integrating all resources from Federal agencies, including National Science Foundation, Department of Defense, Department of Energy, Department of Health and Human Services (NIH), National Institute of Standard Technology (NIST), National Aeronautics and Space Administration (NASA), Environmental Protection Agency (EPA), Homeland Security, United States Department of Agriculture (USDA), and Department of Justice.

The NNI established four goals:

(1) to advance a world-class nanotechnology research and development program;

(2) to foster the transfer of new technologies into products for commercial and public benefit;

(3) to develop and sustain educational resources, a skilled workforce, and supporting infrastructure and tools to advance nanotechnology; and

(4) to support responsible development of nanotechnology. The NNI significantly pushes nanotechnology research forward. In 2006, the prominence of nanotechnology research began to exceed medical research in terms of publication rate. That trend appears to be continuing as a result of the growth of products in commerce using nanotechnology and, for example, five-fold growth in number of countries with nanomaterials research centers.Global Nanotech Pie Chart 041316 opportunities-and-challenges-in-nanotechnologybased-food-packaging-industry-v-teixeira-3-638

The nanoscience and nanotechnology subject category of the Journal Citation Report (JCR) published by Thomson Reuters has increased rapidly. Correspondingly, both impact factors (published by Thomson Reuters) and SCImago Journal Rank values (SJR is published by Elsevier’s Scopus and powered by Google’s PageRank algorithms) of journals in the nanotechnology subject category have increased rapidly [2]. The aggregate impact factor of nanoscience and nanotechnology has been rising at a breathtaking rate, compared with other subject categories, reaching the top 10 after 2011. The hype and hope of nanotechnology challenging many previously unimaginable goals are especially high now, and many believe in forthcoming breakthroughs in the areas of nanomaterial-based diagnostic imaging, complementation of diagnostic tools combined with therapeutic modalities (i.e., theranostics), or nanoencapsulation and nano-carriers of biotechnology products.

Today, it is estimated that total NNI funding, including the fiscal year 2014, is about $170 billion. Currently, there are more than 60 countriesthat have launched national nanotechnology programs [3]. Governments and industry have invested millions of dollars in research funding in this rapidly growing field. By 2015, approximately one quarter trillion dollars will have been invested in nanotechnology by the American government and private sectors collectively. The continuous strategic investment in nanotechnology has made the United States a global leader in the field.

Ten years ago, when AAAS celebrated the 125th anniversary of the journalScience, it invited the President of Chinese Academy of Science (CAS) Chunli Bai to write an essay for the special section Global Voice of Science. The CAS President Chunli Bai’s essay, Ascent of Nanoscience in China [4] described the then development of nanotechnology and nanoscience in the country and openly announced the government’s ambition to compete with other countries in the field. In 2006, the Chinese government announced its Medium and Long-term Plan for the Development of Science and Technology (2006–2020), which identified nanotechnology as “a very promising area that could give China a chance of great-leap-forward development”. The plan introduced the new Chinese Science & Technology policy guidelines, which were later implemented by the Ministry of Science and Technology (MOST) that operates Nanoscience Research as a part of the State Key Science Research Plans. So far the Nanoscience Research program has invested about 1.0 billion RMB to support 28 nanotechnology projects. All of these endeavors led to the recent significantly rapid rise of nanotechnology in China as evidenced by its publications, industrial R&D and applications in the field.

Global Nano II 041316 41hQZPuT5NL._SX298_BO1,204,203,200_The rapid development of nanotechnology-based science and technology in China attracted worldwide attention including from Demos, one of the UK’s most influential think tanks. Led by Wilsdon and Keeley, Demos completed an 18-month study, interviewing many leading scientists and policy makers of 71 Asian organizations, including two well-known Chinese nanotechnology academics Dr. Chen Wang (the then Director of National Center for Nanoscience and Technology) and Academician Zihe Rao (Director of CAS Institute of Biophysics).

After completion of the project, Wilsdon and Keeley published their findings in the book, China: The next science superpower?” [5]. The authors wrote, “China in 2007 is the world’s largest technocracy: a country ruled by scientists and engineers who believe in the power of technology to deliver social and economic progress. Right now, the country is at an early stage in the most ambitious program of research investment since John F Kennedy embarked on the race to the moon. But statistics fail to capture the raw power of the changes that are under way, and the potential for Chinese science and innovation to head in new and surprising directions. Is China on track to become the world’s next science superpower?” Indeed, in recent years, China has emerged not only as a mass manufacturer, but also as one of the world’s leading nanotechnology nations. Many nanomaterial-based semiconductor products come from China and the country dominates in the nanotechnology area of most-cited academic articles: the top eighteen out of the twenty scholars are of Chinese origin [6].

Changes in nanotechnology-related geopolitical landscape

With strong governmental and private sector supports, nanotechnology and nanoscience R&D has developed rapidly in both the USA and China. As shown in Fig. 1A, from 2003 to 2013, the USA led in the area of global nanotechnology publications in terms of the numbers of papers and their quality determined by the number of citations and H-index. China followed USA in the field. For instance, the total nanotechnology publications from USA were 160,870 with total citations of 4056,278, whereas, China published 154,946 papers with total citations of 2049,072. The quality of an article is usually judged by the number of citations it receives, although other measures such as the number of downloads are becoming more accepted and used [2].

The leading countries that published most nanotechnology-related papers and their research focuses (2003–2013). (A) The publications and their quality analysis; the comprehensive normalized values are calculated by the weighted statistics. (B) Key research focuses of the top countries; The keywords are ranked according to their use frequency; (C) publication ratio of China to USA in the selected areas. When the ratio is <1, it indicates that USA is leading in the area, and vice versa. C also indicates that China produced more nanotechnology papers than USA did after 2010.
The leading countries that published most nanotechnology-related papers and their research focuses (2003–2013). (A) The publications and their quality analysis; the comprehensive normalized values are calculated by the weighted statistics. (B) Key research focuses of the top countries; The keywords are ranked according to their use frequency; (C) publication ratio of China to USA in the selected areas. When the ratio is <1, it indicates that USA is leading in the area, and vice versa. C also indicates that China produced more nanotechnology papers than USA did after 2010.

Based on the total number of publications and related citations, we have used weighted statistics to calculate the top countries actively involved in nanotechnology research (see original publication for full details). The statistics show that USA ranks number one, followed by China, Germany, Japan, Korea, France, UK, India, Italy, Spain, Taiwan (China), and others (Fig. 1A). EU countries are not too far behind in the field. Further analysis indicates that the number of nanotechnology-related publications increased from 23,957 in 2003 to 107,371 in 2013 world-wide (an increase of 4.48-folds). Among them, 3592 and 30.479 papers were contributed by China in 2003 and in 2013, respectively, that is an increase of 8.49 folds, which is about 2-fold higher than the global publication increase rate.Global 041316 global_nanotechnology_market_outlook_2022

Bibliometric data of twenty leading nanotechnology journals shows that the USA is leading in nanotechnology research by far (see original publication for full details). The USA contributed 22,067 papers to the twenty journals from 2003 to 2013, whereas, China only published 3421 papers in these journals. If the analysis is limited to papers published in journals with an impact factor >20, the USA originated 1068 papers, followed by EU countries Germany (221), UK (193), France (149), and finally Japan (121). China only produced 76 papers with an impact factor >20, demonstrating that China has some significant hurdles to overcome to join the world’s top countries in nanotechnology development.

Interestingly, China is not lagging behind world leaders in all areas, for example, the gap between the USA and China is narrower in the field of nanomaterial research. Publications from China in Advanced Materials, Advanced Functional Materials, and Angew. Chem. Int. Edit. are not much less than those from the USA. In fact, China is leading in nanocomposites, chemical synthesis, and photocatalysis research (Fig. 1B and C). Chinese scientists published 1712 and 1580 papers in chemical synthesis and photocatalysis (from 2003 to 2013), respectively. The numbers exceed those from India, South Korea, Japan, USA, France, Germany, UK and Italy combined, suggesting that Chinese researchers have evolved their own research focuses and strengths over the years. On the other hand, this fact may also indicate an over-investment of resources in this area.

A list of the top ten universities and institutes world-wide (see original paper for full details), Top 10 Universities for Nanotechnology and Materials Science (U.S. has 5 in the Top 10) as well as those located within USA or China who contribute the most nanotechnology publications, reveals that the authorship of China’s nanotechnology publications is mostly concentrated in a small group of prestigious institutes and universities, reflecting the more centralized governance of China science, while authorship in the USA is more widely distributed. Indeed, the CAS possesses more resources than other competitors in China.

The geopolitical differences between the USA and China are also reflected in nanotechnology-related patent applications and industrialization. The numbers of nanotechnology-related patent applications to the US Patent and Trademark Office (USPTO), or the State Intellectual Property Office of China (SIPO) have increased from 405 in 2000 to 3729 in 2008 in USA, or from 105 in 2000 to 5030 in 2008 in China [7].

According to the China Patent Abstract Database managed by the SIPO, there were 30,863 nanotechnology patent applications from 1985 to 2009, and most of them were published after 2003. The central government has already built several state-level nanotechnology R&D incubators or bases, including the National Center for Nanoscience and Technology of China in Beijing, The State Engineering Research Center for Nanotechnology and Applications in Shanghai, National Institute of Nanotechnology and Engineering in Tianjin, Zhejiang–California International NanoSystems Institute, International Innovation Incubator of Nanotechnology, in Suzhou. In general, Beijing and Shanghai remain the two dominant nanotechnology centers, followed by Jiangsu and Zhejiang, reflecting the regional divergence of Chinese nanotechnology development [8].

The China–USA relationship is as compelling as it is complex. Approximately, one out of ten professionals in Silicon Valley’s high-tech workforce is from mainland China [8]. In today’s global economy, the two great countries compete with each other in nanotechnology in a parallel and compatible manner. Historically, the United States has led the global high-tech and nanotechnology fields. However, the gap between USA and China in nanotechnology has narrowed significantly in recent years and American nanotechnology leadership faces challenges from all over the world.

With improved investment in research infrastructure and funding, China is sustaining the fastest economic growth in the world. Citizens’ participation in nanoscience and nanotechnology-related consensus conferences or stakeholder dialogues has become normal. This has not only had a significant impact on nanotechnology development in China, but also is democratically legitimate. Interest-based civil society interventions play an important role in the polycentric governance of nanoscience and nanotechnology to ensure that the related policies and regulations are made prudently after open argument and discussions [9]. It would be interesting to watch, debate and decide which type of governmental system, the centralized one-party or the almost equally-divided two-party system, can more efficiently and effectively utilize public resources to produce nanotechnology products that better serve their own taxpayers, and the worldwide community as well.


*Fuzhou University and Rutgers University.

The authors are very grateful for supports fromChina MOST grant 2015CB931804 and NSFC grant 81273548 (LJ)81571802 (YG)21275002 (ZW); and US NIH grants (PJS)R01 AI117776 (NIAID/NIH)R37 AI051214 (NIAID/NIH)R01 CA155061 (NCI/NIH), andU54 AR055073 (NIAMS/NIH); the Graduate Student Fellowship Award from the American Association of Pharmaceutical Scientists Foundation (HYD).

This paper was originally published in Nano Today 11(1) (2016) 7–12, doi:10.1016/j.nantod.2016.02.001


[1] B. Clinton. Science, 276 (1997), 1951

Oil Demand Peaks 041316 large_vGY4JHNJO_kYdtxYzoo6F9MhqmWRPtWj8L9rsx-EFZ4

Special from The World Economic Forum

Since the First Industrial Revolution, oil and gas have played a pivotal role in economic transformation and mobility. But now, with the prospects that major economies like the United States, China and European nations will try to shift away from oil, producers are coming to realize that their oil reserves under the ground – sometimes referred to as “black gold” – could become less valuable in the future than they are today.


Of the four scenarios for the future of the industry outlined in a new set of whitepapers from the Global Agenda on the Future of Oil and Gas, three of them envisage this type of world. Factors such as technological advancements, the falling price of batteries that power electric vehicles, and a post-COP21 push for cleaner energy could even drive oil use below 80 million barrels a day by 2040 – 15% lower than today.

     Price of batteries and demand for electric vehicles


We’re already feeling the effect

So what would a future of falling demand mean for the oil and gas industry?


Uncertainty about whether oil demand will continue to grow is already impacting the strategies of oil and gas firms. Through the 2000s and up until last year, the Organization of Petroleum Exporting Countries (OPEC), whose policies influence global oil supply and prices, took a revenues-oriented strategy, believing that scarce oil would be more valuable under the ground than out in the market, as global demand rose exponentially over time. Oil companies, too, responded to this world view by pursuing a business model that maximized adding as many reserves as possible to balance sheets and warehousing expensive assets.


Now, with new trends discussed in a new whitepaper, producers are coming to realize that oil under the ground might soon be less valuable than oil produced and sold in the coming years. This dramatic shift in expectations is changing the operating environment for the future of oil and gas.


A post-oil world: not all doom and gloom


Countries with large, low-cost reserves, such as Saudi Arabia, are rethinking strategies and will have to think twice about delaying production or development of reserves, in case they are unable to monetize those reserves over the long run. Saudi Arabia, for example, has recently announced that it is creating a $2 trillion mega-sovereign wealth fund, funded by sales of current petroleum industry assets, to prepare itself for an age when oil no longer dominates the global economy.


Declining revenues that could be reaped from exploitation of remaining oil reserves would adversely affect national revenues in many countries that have relied on oil as a major economic mainstay. Those countries will face pressing requirements for economic reform, with the risk of sovereign financial defaults rising.


But for the majority of the world’s population, structural transformations related to the future outlook for oil and gas offers an opportunity. If the global economy becomes less oil intensive, vulnerability to supply dislocations and price shocks that have plagued financial markets for decades will fade, with possible positive geopolitical implications. Moreover, many countries have reeled under the pressures of fuel subsidies to growing populations. According to the IMF, fuel subsidies cost $5.3 trillion in 2015 – around 6.5% of global GDP. Lower oil prices and larger range of alternative fuel choices would reverse this burden and lay the groundwork for shallower swings in prices for any one commodity.


    Top 10 energy subsidisers

Image: IMF

Staying competitive in an industry under change


Eventually, players who remain competitive in the oil and gas industry will have to consider whether it can be more profitable to shareholders to develop profitable low-carbon sources of energy as supplement and ultimately replacements for oil and gas revenue sources, especially to maintain market share in the electricity sector.


This will require a change in the oil and gas industry investors’ mindset. To develop this flexible, supplemental leg to traditional oil and gas activities, the oil and gas industry may find new opportunities by addressing the technological challenges associated with the different parts of the renewable energy space, as well as how one can develop efficient combinations of large-scale energy storage and transportation solutions in a world with a lot of variable renewable electricity.


Industry players can benefit from partnerships for flex-fuel technologies to ease infrastructure transitions and improve their resiliency to carbon pricing by achieving carbon efficiency for end-use energy through collaborations with vehicle manufacturers and mobility firms. Such responses will enhance the industry’s attractiveness with customers and investors, and most importantly, will promote a smoother long-term energy transition.


The three whitepapers are available here.

graphenequan 033116


A Rice University laboratory has found a way to turn common carbon fiber into graphene quantum dots, tiny specks of matter with properties expected to prove useful in electronic, optical and biomedical applications.

The Rice lab of materials scientist Pulickel Ajayan, in collaboration with colleagues in China, India, Japan and the Texas Medical Center, discovered a one-step chemical process that is markedly simpler than established techniques for making  quantum dots. The results were published online this month in the American Chemical Society’s journal Nano Letters.

“There have been several attempts to make graphene-based quantum dots with specific electronic and luminescent properties using chemical breakdown or e-beam lithography of graphene layers,” said Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor of Mechanical Engineering and Materials Science and of Chemistry. “We thought that as these nanodomains of graphitized carbons already exist in carbon fibers, which are cheap and plenty, why not use them as the precursor?”

Quantum dots, discovered in the 1980s, are semiconductors that contain a size- and shape-dependent . These have been promising structures for applications that range from computers, LEDs, and lasers to medical imaging devices. The sub-5 nanometer carbon-based quantum dots produced in bulk through the wet chemical process discovered at Rice are highly soluble, and their size can be controlled via the temperature at which they’re created.

Graphene quantum dots: The next big small thing
Green-fluorescing graphene quantum dots created at Rice University surround a blue-stained nucleus in a human breast cancer cell. Cells were placed in a solution with the quantum dots for four hours. The dots, each smaller than 5 …more

The Rice researchers were attempting another experiment when they came across the technique. “We tried to selectively oxidize carbon fiber, and we found that was really hard,” said Wei Gao, a Rice graduate student who worked on the project with lead author Juan Peng, a visiting student from Nanjing University who studied in Ajayan’s lab last year. “We ended up with a solution and decided to look at a few drops with a .”

The specks they saw were bits of graphene or, more precisely, oxidized nanodomains of graphene extracted via chemical treatment of carbon fiber. “That was a complete surprise,” Gao said. “We call them quantum dots, but they’re two-dimensional, so what we really have here are graphene quantum discs.” Gao said other techniques are expensive and take weeks to make small batches of graphene quantum dots. “Our starting material is cheap, commercially available . In a one-step treatment, we get a large amount of quantum dots. I think that’s the biggest advantage of our work,” she said.

Graphene quantum dots: The next big small thing
Dark spots on a transmission electron microscope grid are graphene quantum dots made through a wet chemical process at Rice University. The inset is a closeup of one dot. Graphene quantum dots may find use in electronic, optical and …more

Further experimentation revealed interesting bits of information: The size of the dots, and thus their photoluminescent properties, could be controlled through processing at relatively low temperatures, from 80 to 120 degrees Celsius. “At 120, 100 and 80 degrees, we got blue, green and yellow luminescing dots,” she said.

They also found the dots’ edges tended to prefer the form known as zigzag. The edge of a sheet of graphene — the single-atom-thick form of carbon — determines its electrical characteristics, and zigzags are semiconducting.

Their luminescent properties give graphene quantum dots potential for imaging, protein analysis, cell tracking and other , Gao said. Tests at Houston’s MD Anderson Cancer Center and Baylor College of Medicine on two human breast cancer lines showed the dots easily found their way into the cells’ cytoplasm and did not interfere with their proliferation.

“The green quantum dots yielded a very good image,” said co-author Rebeca Romero Aburto, a graduate student in the Ajayan Lab who also studies at MD Anderson. “The advantage of graphene dots over fluorophores is that their fluorescence is more stable and they don’t photobleach. They don’t lose their fluorescence as easily. They have a depth limit, so they may be good for in vitro and in vivo (small animal) studies, but perhaps not optimal for deep tissues in humans.

“But everything has to start in the lab, and these could be an interesting approach to further explore for bioimaging,” Romero Alburto said. “In the future, these graphene could have high impact because they can be conjugated with other entities for sensing applications, too.”

Explore further: Single Atom Quantum Dots Bring Real Devices Closer (Video)

More information: Nano Lett., Article ASAP DOI: 10.1021/nl2038979

Provided by:Rice University



Ciphers and invisible ink – many of us experimented with these when we were children. A team of Chinese scientists has now developed a clever, high-tech version of “invisible ink”. As reported in the journal Angewandte Chemie, the ink is based on carbon nitride quantum dots. Information written with this ink is not visible under ambient or UV light; however, it can be seen with a fluorescence microplate reader. The writing can be further encrypted or decrypted by quenching or recovering the fluorescence with different reagents.

Fluorescing security inks are primarily used to ensure the authenticity of products or documents, such as certificates, stock certificates, transport documents, currency notes, or identity cards. Counterfeits may cost affected companies lost profits, and the poor quality of the false products may damage their reputations. In the case of sensitive products like pharmaceuticals and parts for airplanes and cars, human lives and health may be endangered. Counterfeiters have discovered how to imitate UV tags but it is significantly harder to copy security inks that are invisible under UV light.
Researchers working with Xinchen Wang and Liangqia Guo at Fuzhou University have now introduced an inexpensive “invisible” ink that increases the security of encoded data while also making it possible to encrypt and decrypt secure information.
The new ink is based on water-soluble quantum dots, nanoscopic “heaps” of a semiconducting material. Quantum dots have special optoelectronic properties that can be controlled by changing the size of the dots.

The scientists used quantum dots made from graphitic carbon nitride. This material consists of ring systems made of carbon and nitrogen atoms linked into two-dimensional molecular layers. The structure is similar to that of graphite (or graphene), one of the forms of pure carbon, but also has semiconductor properties.
Information written with this new ink is invisible under ambient and UV light because it is almost transparent in the visible light range and emits fluorescence with a peak in the UV range. The writing only becomes visible under a microplate reader like those used in biological fluorescence tests. In addition, the writing can be further encrypted and decrypted: treatment with oxalic acid renders it invisible to the microplate reader. Treatment with sodium bicarbonate reverses this process, making the writing visible to the reader once more.
Explore further: Luminescent ink from eggs
More information: Zhiping Song et al. Invisible Security Ink Based on Water-Soluble Graphitic Carbon Nitride Quantum Dots, Angewandte Chemie International Edition (2016). DOI: 10.1002/anie.201510945
Journal reference: Angewandte Chemie Angewandte Chemie International Edition
Provided by: Angewandte Chemie

China LI Battery 033116 56efc495569e8

Recently, researchers at Tsinghua University, China have proposed a graphene-based nanostructured lithium metal anode for lithium metal batteries to inhibit dendrite growth and improve electrochemistry performance. They report their findings in Advanced Materials, published on March 16, 2016.

“Widely used lithium-ion batteries cannot satisfy the increasing requirement of energy storage systems in portable electronics and electric vehicles. New anode batteries, like Li-S and Li-air batteries, are highly sought. Lithium metal provides an extremely high theoretical specific capacity, which is almost 10 times more energy than graphite,” said Prof. Qiang Zhang, at the Department of Chemical Engineering, Tsinghua University. “However, the practical applications of lithium metals are strongly hindered by lithium dendrite growth in continuous cycles. This induces safety concerns. The lithium dendrites may cause internal short circuits resulting in fire. Furthermore, the formation of lithium dendrites induces very low cycling efficiency.” The dendrite growth and unstable solid electrolyte interphase consume large amount of lithium and electrolyte, and therefore leading to irreversible battery capacity losses. Consequently, inhibiting the dendrites growth is highly expected.

Many approaches have been proposed to retard the growth of dendrites through electrolyte modification, artificial solid electrolyte interphase layers, electrode construction, and others. “We noticed that by decreasing the local current density heavily, lithium dendrite growth could be efficiently inhibited. Based on this concept, we employed unstacked graphene with an ultrahigh specific surface area to build a nanostructured anode. And it turned out to be a very efficient idea,” said Rui Zhang, a Ph.D. student and the first author. “Additionally, we have employed the dual-salt electrolyte to acquire more stable and more flexible solid electrolyte interphase, which can protect the lithium metal from further reactions with electrolyte.”

This graphene-based anode offered great improvement, including (1) ultralow local current density on the surface of graphene anode (a ten-thousandth of that on routine Cu foil-based anodes) induced by the large specific surface area of 1666 m2 g-1, which inhibited and brought uniform lithium deposition morphology; (2) high stable cycling capacity of 4.0 mAh mg-1 induced by the high pore volume (1.65 cm3 g-1) of unstacked graphene, over 10 times of the graphite anode in lithium-ion batteries (0.372 mAh mg-1); (3) high electrical conductivity (435 S cm-1), leading to low interface impedance, stable charging/discharging performance, and high cycling efficiencies.

“We hope that our research can point out a new strategy to deal with the dendrite challenge in lithium metal anodes. The ultralow local current density induced by conductive nanostructured anodes with high specific surface area can help improve the stability and electrochemistry performance of lithium metal anodes,” said Xin-Bing Cheng, a co-author of the work. Future investigation is required to design preferable anode structures and to produce more protective solid electrolyte interphase layers. The researchers also call for additional study of the diffusion behavior of Li ions and electrons in the process of lithium depositing and stripping to advance the commercial applications of lithium metal anodes.

Explore further: Nanostructure enlightening dendrite-free metal anode

More information: R. Zhang, X.-B. Cheng, C.-Z. Zhao, H.-J. Peng, J.-L. Shi, J.-Q. Huang, J. Wang, F. Wei, Q. Zhang. Conductive Nanostructured Scaffolds Render Low Local Current Density to Inhibit Lithium Dendrite Growth. Adv. Mater. 2016, 28, 2155-2162. DOI: 10.1002/adma.201504117.

Solar Fuels Artificial Leaf 032516 160321110445_1_540x360A team at the HZB Institute for Solar Fuels has developed a process for providing sensitive semiconductors for solar water splitting (“artificial leaves”) with an organic, transparent protective layer. The extremely thin protective layer made of carbon chains is stable, conductive, and covered with catalysing nanoparticles of metal oxides. These accelerate the splitting of water when irradiated by light. The team was able to produce a hybrid silicon-based photoanode structure that evolves oxygen at current densities above 15 mA/cm2. The results have now been published in Advanced Energy Materials.

Solar Fuels Artificial Leaf 032516 160321110445_1_540x360

The illustration shows the structure of the sample: n-doped silicon layer (black), a thin silicon oxide layer (gray), an intermediate layer (yellow) and finally the protective layer (brown) to which the catalysing particles are applied. The acidic water is shown in green.
Credit: M. Lublow

The “artificial leaf” consists in principle of a solar cell that is combined with further functional layers. These act as electrodes and additionally are coated with catalysts. If the complex system of materials is submerged in water and illuminated, it can decompose water molecules. This causes hydrogen to be generated that stores solar energy in chemical form. However, there are still several problems with the current state of technology. For one thing, sufficient light must reach the solar cell in order to create the voltage for water splitting — despite the additional layers of material. Moreover, the semiconductor materials that the solar cells are generally made of are unable to withstand the typical acidic conditions for very long. For this reason, the artificial leaf needs a stable protective layer that must be simultaneously transparent and conductive.

Catalyst used twice

The team worked with samples of silicon, an n-doped semiconductor material that acts as a simple solar cell to produce a voltage when illuminated. Materials scientist Anahita Azarpira, a doctoral student in Dr. Thomas Schedel-Niedrig’s group, prepared these samples in such a way that carbon-hydrogen chains on the surface of the silicon were formed. “As a next step, I deposited nanoparticles of ruthenium dioxide, a catalyst,” Azarpira explains. This resulted in formation of a conductive and stable polymeric layer only three to four nanometres thick. The reactions in the electrochemical prototype cell were extremely complicated and could only be understood now at HZB.

The ruthenium dioxide particles in this new process were being used twice for the first time. In the first place, they provide for the development of an effective organic protective layer. This enables the process for producing protective layers — normally very complicated — to be greatly simplified. Only then does the catalyst do its “normal job” of accelerating the partitioning of water into oxygen and hydrogen.

Organic protection layer combines excellent stability with high current densities

The silicon electrode protected with this layer achieves current densities in excess of 15 mA/cm2. This indicates that the protection layer shows good electronic conductivity, which is by no means trivial for an organic layer. In addition, the researchers observed no degradation of the cell — the yield remained constant over the entire 24-hour measurement period. It is remarkable that an entirely different material has been favoured as an organic protective layer: graphene. This two-dimensional material has been the subject of much discussion, yet up to now could only be employed for electrochemical processes with limited success, while the protective layer developed at HZB works quite wel . Because the novel material could lend itself for the deposition process as well as for other applications, we are trying to acquire international protected property rights,” says Thomas Schedel-Niedrig, head of the group.

Story Source:

The above post is reprinted from materials provided by Helmholtz-Zentrum Berlin für Materialien und Energie. Note: Materials may be edited for content and length.

Journal Reference:

  1. Anahita Azarpira, Thomas Schedel-Niedrig, H.-J. Lewerenz, Michael Lublow. Sustained Water Oxidation by Direct Electrosynthesis of Ultrathin Organic Protection Films on Silicon. Advanced Energy Materials, 2016; DOI: 10.1002/aenm.201502314
MSU Fibers 032516 160324104809_1_540x360A microbial protein fiber discovered by a MSU’s Gemma Reguera transports charges at rates high enough to be applied in manmade nanotechnologies.
Credit: Kurt Stepnitz

“This microbial nanowire is made of but a single peptide subunit,” said Gemma Reguera, lead author and MSU microbiologist. “Being made of protein, these organic nanowires are biodegradable and biocompatible. This discovery thus opens many applications in nanoelectronics such as the development of medical sensors and electronic devices that can be interfaced with human tissues.”

Since existing nanotechnologies incorporate exotic metals into their designs, the cost of organic nanowires is much more cost effective as well, she added.

How the nanowires function in nature is comparable to breathing. Bacterial cells, like humans, have to breathe. The process of respiration involves moving electrons out of an organism. Geobacter bacteria use the protein nanowires to bind and breathe metal-containing minerals such as iron oxides and soluble toxic metals such as uranium. The toxins are mineralized on the nanowires’ surface, preventing the metals from permeating the cell.

Reguera’s team purified their protein fibers, which are about 2 nanometers in diameter. Using the same toolset of nanotechnologists, the scientists were able to measure the high velocities at which the proteins were passing electrons.

“They are like power lines at the nanoscale,” Reguera said. “This also is the first study to show the ability of electrons to travel such long distances — more than a 1,000 times what’s been previously proven — along proteins.”

The researchers also identified metal traps on the surface of the protein nanowires that bind uranium with great affinity and could potentially trap other metals. These findings could provide the basis for systems that integrate protein nanowires to mine gold and other precious metals, scrubbers that can be deployed to immobilize uranium at remediation sites and more.

Reguera’s nanowires also can be modified to seek out other materials in which to help them breathe.

“The Geobacter cells are making these protein fibers naturally to breathe certain metals. We can use genetic engineering to tune the electronic and biochemical properties of the nanowires and enable new functionalities. We also can mimic the natural manufacturing process in the lab to mass-produce them in inexpensive and environmentally friendly processes,” Reguera said. “This contrasts dramatically with the manufacturing of humanmade inorganic nanowires, which involve high temperatures, toxic solvents, vacuums and specialized equipment.”

This discovery came from truly listening to bacteria, Reguera said.

“The protein is getting the credit, but we can’t forget to thank the bacteria that invented this,” she said. “It’s always wise to go back and ask bacteria what else they can teach us. In a way, we are eavesdropping on microbial conversations. It’s like listening to our elders, learning from their wisdom and taking it further.”

Story Source:

The above post is reprinted from materials provided by Michigan State University. Note: Materials may be edited for content and length.

Journal Reference:

  1. Sanela Lampa-Pastirk, Joshua P. Veazey, Kathleen A. Walsh, Gustavo T. Feliciano, Rebecca J. Steidl, Stuart H. Tessmer, Gemma Reguera. Thermally activated charge transport in microbial protein nanowires. Scientific Reports, 2016; 6: 23517 DOI: 10.1038/srep23517
GNT Thumbnail Alt 3 2015-page-001Advancements in nanotechnology could fundamentally change global approaches to manufacturing, medicine, healthcare, and the environment.


In this lecture Dr. Eric Drexler, Senior Visiting Fellow, Oxford Martin School, will look at current advances in the field of advanced nanotechnology, and the impacts and potential applications of their widespread implementation, and Dr. Sonia Trigueros, Co-Director of the Oxford Martin Programme on Nanotechnology, and Oxford Martin Senior Fellow, will consider how targeted nanomedicine could change how we treat disease in the future.

Published on Jan 28, 2016


No More nomorewashin
Cotton textile covered with nanostructures invisible to the naked eye. Image magnified 200 times. Credit: RMIT University

A spot of sunshine is all it could take to get your washing done, thanks to pioneering nano research into self-cleaning textiles.

Researchers at RMIT University in Melbourne, Australia, have developed a cheap and efficient new way to grow special —which can degrade organic matter when exposed to light—directly onto .

The work paves the way towards nano-enhanced textiles that can spontaneously clean themselves of stains and grime simply by being put under a light bulb or worn out in the sun.

Dr Rajesh Ramanathan said the process developed by the team had a variety of applications for catalysis-based industries such as agrochemicals, pharmaceuticals and natural products, and could be easily scaled up to industrial levels.

“The advantage of textiles is they already have a 3D structure so they are great at absorbing light, which in turn speeds up the process of degrading organic matter,” he said.

“There’s more work to do to before we can start throwing out our washing machines, but this advance lays a strong foundation for the future development of fully self-cleaning textiles.”

The researchers from the Ian Potter NanoBioSensing Facility and NanoBiotechnology Research Lab at RMIT worked with copper and silver-based nanostructures, which are known for their ability to absorb visible light.

No more washing: Nano-enhanced textiles clean themselves with light
The red color indicates the presence of silver nanoparticles — the total coverage on the image shows the nanostructures grown by the RMIT team are present throughout the textile. Image magnified 200 times. Credit: RMIT University

When the nanostructures are exposed to light, they receive an energy boost that creates ““. These “hot electrons” release a burst of energy that enables the nanostructures to degrade organic matter.

The challenge for researchers has been to bring the concept out of the lab by working out how to build these nanostructures on an industrial scale and permanently attach them to textiles.

The RMIT team’s novel approach was to grow the nanostructures directly onto the textiles by dipping them into a few solutions, resulting in the development of stable nanostructures within 30 minutes.

No more washing: Nano-enhanced textiles clean themselves with light
Close-up of the nanostructures grown on cotton textiles by RMIT University researchers. Image magnified 150,000 times. Credit: RMIT University

When exposed to , it took less than six minutes for some of the nano-enhanced textiles to spontaneously clean themselves.

“Our next step will be to test our nano-enhanced textiles with organic compounds that could be more relevant to consumers, to see how quickly they can handle common stains like tomato sauce or wine,” Ramanathan said.

The research is published on March 23, 2016 in the high-impact journal Advanced Materials Interfaces.

Explore further: Silver in the washing machine: Nanocoatings release almost no nanoparticles

More information: Samuel R. Anderson et al. Robust Nanostructured Silver and Copper Fabrics with Localized Surface Plasmon Resonance Property for Effective Visible Light Induced Reductive Catalysis, Advanced Materials Interfaces (2016). DOI: 10.1002/admi.201500632

Drop of Water 160322080534_1_540x360
Drop of water. “Hydrogen production through an electrochemical process is at the heart of key renewable energy technologies including water splitting and hydrogen fuel cells,” says Professor Yao.
Credit: © Deyan Georgiev / Fotolia

Groundbreaking research at Griffith University is leading the way in clean energy, with the use of carbon as a way to deliver energy using hydrogen.

Professor Xiangdong Yao and his team from Griffith’s Queensland Micro- and Nanotechnology Centre have successfully managed to use the element to produce hydrogen from water as a replacement for the much more costly platinum.

“Hydrogen production through an electrochemical process is at the heart of key renewable energy technologies including water splitting and hydrogen fuel cells,” says Professor Yao.

“Despite tremendous efforts, exploring cheap, efficient and durable electrocatalysts for hydrogen evolution still remains a great challenge.

“Platinum is the most active and stable electrocatalyst for this purpose, however its low abundance and consequent high cost severely limits its large-scale commercial applications.

“We have now developed this carbon-based catalyst, which only contains a very small amount of nickel and can completely replace the platinum for efficient and cost-effective hydrogen production from water.

“In our research, we synthesize a nickel-carbon-based catalyst, from carbonization of metal-organic frameworks, to replace currently best-known platinum-based materials for electrocatalytic hydrogen evolution.

“This nickel-carbon-based catalyst can be activated to obtain isolated nickel atoms on the graphitic carbon support when applying electrochemical potential, exhibiting highly efficient hydrogen evolution performance and impressive durability.”

Proponents of a hydrogen economy advocate hydrogen as a potential fuel for motive power including cars and boats and on-board auxiliary power, stationary power generation (e.g., for the energy needs of buildings), and as an energy storage medium (e.g., for interconversion from excess electric power generated off-peak).

Professor Yao says that this work may enable new opportunities for designing and tuning properties of electrocatalysts at atomic scale for large-scale water electrolysis.

Story Source:

The above post is reprinted from materials provided by Griffith University. Note: Materials may be edited for content and length.

Journal Reference:

  1. Lili Fan, Peng Fei Liu, Xuecheng Yan, Lin Gu, Zhen Zhong Yang, Hua Gui Yang, Shilun Qiu, Xiangdong Yao.Atomically isolated nickel species anchored on graphitized carbon for efficient hydrogen evolution electrocatalysis. Nature Communications, 2016; 7: 10667 DOI: 10.1038/ncomms10667

1 2 3 4 5 6 7 29
Recent Posts