New strides have been made in turning water into fuel. Researchers from University of Chicago and University of Wisconsin recently announced new techniques they’ve discovered that can help increase the efficiency of the process of extracting hydrogen from water molecules.
The idea is to split water molecules into their component atoms: hydrogen and oxygen. The hydrogen can then be harvested to create hydrogen fuel. If the water can be split into its pieces using a renewable energy source such as sunlight, then the proposition becomes more interesting.
Experimental scientist Kyoung-Shin Choi was exploring ways to break apart the hydrogen and oxygen atoms in water. The process involves two electrodes, which create a current that delivers the necessary energy needed to excite the electrons and split the water molecules apart. One electrode is outfitted with solar sensors that absorb sunlight and use the energy from the photons to create the current. Then, the electrons need to be able to flow freely from the solar electrode to the counter electrode, in order to be used to split the water molecules.
In her experiments, Choi used an electrode made of bismuth vanadate (a semi-conductive compound), heated to a high temperature of 350 degrees Celsius, and introduced nitrogen gas into the process by flowing it over the electrode. She found that the addition of nitrogen to the compound helped the electrode absorb more photons — thereby using more of the energy available to energize the electrons — but is also helped the electrons move more efficiently to the opposing electrode.
“Our study will encourage researchers in the field to develop ways to improve multiple processes using a single treatment,” said Choi, who is professor of chemistry at the University of Wisconsin. “So it’s not just about achieving higher efficiency, it’s about providing a strategy for the field.”
The other researcher, theorist Giulia Galli, is Liew Family Professor of Electronic Structure and Simulations at University of Chicago’s Institute for Molecular Engineering.n“People can use these concepts –incorporation of a new element and new defects into the material — in other systems to try to improve their efficiency,” said Galli. “These are very general concepts that could also be applied to other materials.”
Uses for Water-as-Fuel
The potential of using water as a renewable fuel source is largely discussed today with internal-combustion car engines. A company in Japan called Genepax created a car that turned water into hydrogen fuel in 2008, claiming the car ran on 100% water. The claims were dubious and the company was unable to get much traction; it has since been shuttered.
But other car makers are experimenting with more promising uses of water in alternative fuel systems. Audi has partnered with Germany-based start-up Sunfire in a pilot plant that generates “e-diesel.” The process uses electricity to separate the hydrogen and oxygen atoms, then mixes the hydrogen with carbon oxide — derived from carbon dioxide (CO2) — which then undergoes a chemical reaction resulting in a liquid of long chain hydrocarbons, also known as “blue crude.” The blue crude is then refined into synthetic diesel fuel, or “e-diesel,” which can be used in any diesel vehicle. The system can be made even more clean when the initial electricity is derived from a renewable source — such as solar or wind — and when the CO2 is captured directly from the atmosphere.
The e-diesel doesn’t contain sulphur or any fossil fuels, it helps the engine run more quietly and creates fewer pollutants than traditional diesel, the company said.
Feature image: by Peat Bakke