Efficient, Low-Cost Catalyst To Produce Hydrogen

A nanostructured composite material developed at UC Santa Cruz has shown impressive performance as a catalyst for the electrochemical splitting of water to produce hydrogen. An efficient, low-cost catalyst is essential for realizing the promise of hydrogen as a clean, environmentally friendly fuel.

Researchers led by Shaowei Chen, professor of chemistry and biochemistry at UC Santa Cruz, have been investigating the use of carbon-based nanostructured materials as catalysts for the reaction that generates hydrogen from water. In one recent study, they obtained good results by incorporating ruthenium ions into a sheet-like nanostructure composed of carbon nitride. Performance was further improved by combining the ruthenium-doped carbon nitride with graphene, a sheet-like form of carbon, to form a layered composite.

The bonding chemistry of ruthenium with nitrogen in these nanostructured materials plays a key role in the high catalytic performance,” Chen said. “We also showed that the stability of the catalyst is very good.”

Currently, the most efficient catalysts for the electrochemical reaction that generates hydrogen from water are based on platinum, which is scarce and expensive. Carbon-based materials have shown promise, but their performance has not come close to that of platinum-based catalysts.

In the new composite material developed by Chen’s lab, the ruthenium ions embedded in the carbon nitride nanosheets change the distribution of electrons in the matrix, creating more active sites for the binding of protons to generate hydrogen. Adding graphene to the structure further enhances the redistribution of electrons.

The new findings were published in ChemSusChem.

Source: https://news.ucsc.edu/

Sun + Wastewater Produce Hydrogen Fuel

A research team led by Yat Li, associate professor of chemistry at the University of California, Santa Cruz, developed an hybrid solar-microbial device that combines a microbial fuel cell (MFC) and a type of solar cell called a photoelectrochemical cell (PEC). In the MFC component, bacteria degrade organic matter in the wastewater, generating electricity in the process. The biologically generated electricity is delivered to the PEC component to assist the solar-powered splitting of water (electrolysis) that generates hydrogen and oxygen.
Qian said the researchers are optimistic about the commercial potential for their invention. Currently they are planning to scale up the small laboratory device to make a larger 40-liter prototype continuously fed with municipal wastewater. If results from the 40-liter prototype are promising, they will test the device on site at the wastewater treatment plant. Li’s group collaborated with researchers at Lawrence Livermore National Laboratory (LLNL) who have been studying electrogenic bacteria and working to enhance MFC performance.

hydrogen-electric car
When fed with wastewater and illuminated in a solar simulator, the PEC-MFC device showed continuous production of hydrogen gas at an average rate of 0.05 cubic meters per day, according to LLNL researcher and coauthor Fang Qian.
The MFC will be integrated with the existing pipelines of the plant for continuous wastewater feeding, and the PEC will be set up outdoors to receive natural solar illumination,” Qian said. “Fortunately, the Golden State is blessed with abundant sunlight that can be used for the field test,” Li added.
The findiings are reported in a paper published in the American Chemical Society journal ACS Nano.
Source: http://news.ucsc.edu/

Fast Virus Test At The Medical Office

Two independent teams (University of Caliofornia Los AngelesUCLA– and University of California Santa Cruz UCSC-) have developed new optics-based methods for determining the exact viral load of a sample by counting individual virus particles. These new methods are faster and cheaper than standard tests and they offer the potential to conduct the measurements in a medical office or hospital instead of a laboratory. The teams will present their latest results at the Conference on Lasers and Electro-Optics (CLEO: 2013), to be held June 9-14, in San Jose, Calif.

optofluidic chip
Photograph of 1cm x 1cm optofluidic chip for direct detection of viral nucleic acids

Because viruses are very small–less than 100 billionths of a meter–compared to the wavelength of light, conventional light microscopy has difficulty producing an image due to weak scattering of sub-wavelength particles,” says Aydogan Ozcan of UCLA. When lighted, the team’s new nanolens-nanoparticle assembly projects a hologram that can be recorded using a CMOS imager chip (a type of semiconductor-based light detector) and digitally reconstructed to form an optical image of the particle. “The resulting image improves the field-of-view of a conventional optical microscope by two orders of magnitude,” says Ozcan.
Source: http://www.osa.org/