Tag Archives: Hui Wang

Another day, another solar cell improvement: replacing platinum with 3D graphene

On the plus side, this may replace platinum but it does seem to be one of a plethora of solar cell improvements that don’t make much difference in the current marketplace as this and other improvements are still at the laboratory stage.  Still, it’s encouraging to remember that scientific and technical progress in an area can be agonizingly slow in the early stages only to gain speed at an exponential rate in later stages of development. Fingers crossed this is the case with solar cells.

From the Aug. 20, 2013 Michigan Technological University news release by Marcia Goodrich (also on EurekAlert),

One of the most promising types of solar cells has a few drawbacks. …

Dye-sensitized solar cells are thin, flexible, easy to make and very good at turning sunshine into electricity. However, a key ingredient is one of the most expensive metals on the planet: platinum. While only small amounts are needed, at $1,500 an ounce, the cost of the silvery metal is still significant.

Yun Hang Hu, the Charles and Caroll McArthur Professor of Materials Science and Engineering [Michigan Technological University], has developed a new, inexpensive material that could replace the platinum in solar cells without degrading their efficiency: 3D graphene.

Regular graphene is a famously two-dimensional form of carbon just a molecule or so thick. Hu and his team invented a novel approach to synthesize a unique 3D version with a honeycomb-like structure. To do so, they combined lithium oxide with carbon monoxide in a chemical reaction that forms lithium carbonate (Li2CO3) and the honeycomb graphene. The Li2CO3 helps shape the graphene sheets and isolates them from each other, preventing the formation of garden-variety graphite.  Furthermore, the Li2CO3 particles can be easily removed from 3D honeycomb-structured graphene by an acid.

The researchers determined that the 3D honeycomb graphene had excellent conductivity and high catalytic activity, raising the possibility that it could be used for energy storage and conversion. So they replaced the platinum counter electrode in a dye-sensitized solar cell with one made of the 3D honeycomb graphene. Then they put the solar cell in the sunshine and measured its output.

The cell with the 3D graphene counter electrode converted 7.8 percent of the sun’s energy into electricity, nearly as much as the conventional solar cell using costly platinum (8 percent).

Synthesizing the 3D honeycomb graphene is neither expensive nor difficult, said Hu, and making it into a counter electrode posed no special challenges.

Here’s a link to and a citation for the research paper,

3D Honeycomb-Like Structured Graphene and Its High Efficiency as a Counter-Electrode Catalyst for Dye-Sensitized Solar Cells by Yun Hang Hu, Hui Wang, Franklin Tao, Dario J. Stacchiola, and Kai Sun. Angewandte Chemie, International Edition, Article first published online: 29 JUL 2013 DOI: 10.1002/anie.201303497

The article is behind a paywall.

Squeezing blood from rice

They are squeezing the equivalent of human blood protein (blood-derived human serum albumin [HSA]) from transgenic rice according to the research paper (open access) published in the Proceedings of the National Academy of Sciences (PNAS). From the abstract in PNAS,

Human serum albumin (HSA) is widely used in clinical and cell culture applications. Conventional production of HSA from human blood is limited by the availability of blood donation and the high risk of viral transmission from donors. Here, we report the production of Oryza sativa recombinant HSA (OsrHSA) from transgenic rice seeds. … Physical and biochemical characterization of OsrHSA revealed it to be equivalent to plasma-derived HSA (pHSA). The efficiency of OsrHSA in promoting cell growth and treating liver cirrhosis in rats was similar to that of pHSA. Furthermore, OsrHSA displays similar in vitro and in vivo immunogenicity as pHSA. Our results suggest that a rice seed bioreactor produces cost-effective recombinant HSA that is safe and can help to satisfy an increasing worldwide demand for human serum albumin.

The Oct. 31, 2011 news item about this research on physorg.com notes this about the demand for HSA,

“Our results suggest that a rice seed bioreactor produces cost-effective recombinant HSA that is safe and can help to satisfy an increasing worldwide demand for human serum albumin,” said the study.

The protein is often used in the manufacture of vaccines and drugs and is given to patients with serious burn injuries, hemorrhagic shock and liver disease, the researchers said.

In 2007, a shortage in China led to price spikes and a brief rise in the number of fraudulent albumin medicines on the market.

Concerns have also been raised about the potential for the transmission of hepatitis and HIV, since the protein comes from human blood.

The lead author, Yang He is from Wuhan University, China. Other listed authors are:  Tingting Ning, Tingting Xie, Qingchuan Qiu, Liping Zhang, Yunfang Sun, Daiming Jiang, Kai Fu, Fei Yin, Wenjing Zhang, Lang Shen, Hui Wang, Jianjun Li, Qishan Lin, Yunxia Sun, Hongzhen Li, Yingguo Zhu, and Daichang Yang. This list gets more interesting if you have time to check out their affiliations (at the PNAS website) which include the National Research Council of Canada’s Institutes for Biological Sciences, University of Albany, New York State and Joinn Laboratory, Beijing and you get a sense of how much cooperation it takes to do this research. Finally, the paper is titled, Large-scale production of functional human serum albumin from transgenic rice seeds.