Clean Renewable Source Of Hydrogen Fuel For Electric Car

Rice University scientists have created an efficient, simple-to-manufacture oxygen-evolution catalyst that pairs well with semiconductors for solar water splitting, the conversion of solar energy to chemical energy in the form of hydrogen and oxygen.

anode RiceA photo shows an array of titanium dioxide nanorods with an even coating of an iron, manganese and phosphorus catalyst. The combination developed by scientists at Rice University and the University of Houston is a highly efficient photoanode for artificial photosynthesis. Click on the image for a larger version

The lab of Kenton Whitmire, a Rice professor of chemistry, teamed up with researchers at the University of Houston and discovered that growing a layer of an active catalyst directly on the surface of a light-absorbing nanorod array produced an artificial photosynthesis material that could split water at the full theoretical potential of the light-absorbing semiconductor with sunlight. An oxygen-evolution  catalyst splits water into hydrogen and oxygen. Finding a clean renewable source of hydrogen fuel is the focus of extensive research, but the technology has not yet been commercialized.

The Rice team came up with a way to combine three of the most abundant metalsiron, manganese and phosphorus — into a precursor that can be deposited directly onto any substrate without damaging it. To demonstrate the material, the lab placed the precursor into its custom chemical vapor deposition (CVD) furnace and used it to coat an array of light-absorbing, semiconducting titanium dioxide nanorods. The combined material, called a photoanode, showed excellent stability while reaching a current density of 10 milliamps per square centimeter, the researchers reported.

The results appear in two new studies. The first, on the creation of the films, appears in Chemistry: A European Journal. The second, which details the creation of photoanodes, appears in ACS Nano.


How To Produce Cheap Hydrogen Fuel

Humans have for ages taken cues from nature to build their own devices, but duplicating the steps in the complicated electronic dance of photosynthesis remains one of the biggest challenges and opportunities for chemists.

Currently, the most efficient methods we have for making fuel – principally, hydrogen – from sunlight and water involve rare and expensive metal catalysts, such as platinum. In a new study, researchers at the U.S. Department of Energy’s Argonne National Laboratory have found a new, more efficient way to link a less expensive synthetic cobalt-containing catalyst to an organic light-sensitive molecule, called a chromophore.
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Although cobalt is significantly less efficient than platinum when it comes to light-induced hydrogen generation, the drastic price difference between the two metals makes cobalt the obvious choice as the foundation for a synthetic catalyst“, said Argonne chemist Karen Mulfort. “Cobalt doesn’t have to be as efficient as platinum because it is just so much cheaper“.


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.

Green Hydrogen Fuel For Electric Car

A protein found in the membranes of ancient microorganisms that live in desert salt flats could offer a new way of using sunlight to generate environmentally friendly hydrogen fuel, according to a new study by researchers at the U.S. Department of Energy’s Argonne National Laboratory. Argonne nanoscientist Elena Rozhkova and her colleagues combined a pigment called bacteriorhodopsin with semiconducting nanoparticles to create a system that uses light to spark a catalytic process that creates hydrogen fuel.

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Scientists have been aware of the potential of titanium dioxide nanoparticles for light-based reactions since the early 1970s, when Japanese researchers discovered that a titanium dioxide electrode exposed to bright ultraviolet light could split water molecules in a phenomenon that came to be known as the Honda-Fujishima effect.
Titanium dioxide alone reacts with ultraviolet light, but not with visible light, so we used biological photoreactive molecules as a building block to create a hybrid system that could use visible light efficiently,” Rozhkova said.


Ultrathin Films Achieve High Solar Energy Efficiency

Using the power of the sun and ultrathin films of iron oxide (commonly known as rust), Technion-Israel Institute of Technology researchers have found a novel way to split water molecules to hydrogen and oxygen. The breakthrough, published this week in Nature Materials, could lead to less expensive, more efficient ways to store solar energy in the form of hydrogen-based fuels. This could be a major step forward in the development of viable replacements for fossil fuels.

“Our approach is the first of its kind,” says lead researcher Associate Prof. Avner Rothschild, of the Department of Materials Science and Engineering at Technion-Israel Institute of Technology. “We have found a way to trap light in ultrathin films of iron oxide that are 5,000 thinner than an office paper. This enables achieving high solar energy conversion efficiency and low materials and production costs.
Let’s remind that two days ago Swiss Scientists from Ecole Polytechnique Fédérale de Lausanne (EPFL) – Switzerland – have declared that they are producing hydrogen from sunlight, water and rust. Their prototypes shared the same basic principle: a dye-sensitized solar cell – invented by Michael Grätzel, a colleague from University of Geneva, – combined with an oxide-based semiconductor. The device is completely self-contained. More on


Efficient hydrogen fuel cells for electric cars

Chemical reactions on the surface of metal oxides, such as titanium dioxide and zinc oxide, are important for applications such as solar cells that convert the sun's energy to electricity. Now University of Washington scientists have found that a previously unappreciated aspect of those reactions could be key in developing more efficient energy systems.

New systems could include cells that would produce more electricity from the sun's rays, or hydrogen fuel cells efficient enough for use in automobiles, said James Mayer, a UW chemistry professor. "As we think about building a better energy future, we have to develop more efficient ways to convert chemical energy into electrical energy and vice versa," said Mayer.

Chemical reactions that change the oxidation state of molecules on the surface of metal oxides historically have been seen as a transfer solely of electrons. The new research shows that, at least in some reactions, the transfer process includes coupled electrons and protons.