Scientists have determined that an inexpensive semiconductor material can be tweaked to generate hydrogen from water using sunlight, a revelation that may have the potential to bolster the renewable energy sector.
The research, published in the Physical Review Journal, was funded by the U.S. Department of Energy and led by scientists at the UK Center for Computational Sciences and the University of Louisville Conn Center for Renewable Energy Research.
The team demonstrated that an alloy formed by a two percent substitution of antimony in gallium nitride has electrical properties that enable solar light energy to split water molecules into hydrogen and oxygen through a process known as photoelectrochemical water splitting. The researchers found that when the alloy is submerged in water and exposed to sunlight, the chemical bond between the hydrogen and oxygen molecules break, allowing the hydrogen to be collected to separately.
We decided to go against the conventional wisdom and start with some easy-to-produce materials, even if they lacked the right arrangement of electrons to meet [photoelectrochemical] criteria. Our goal was to see if a minimal 'tweaking' of the electronic arrangement in these materials would accomplish the desired results, said Madhu Menon, a professor at the UK Center for Computational Sciences, in a statement.
The findings may help advance the future of solar energy. Hydrogen is a key component in many renewable energy resources: it can be used in fuel cells to generate electricity, burned to produce heat and used in internal-combustion engines to run vehicles. When its combusted, hydrogen combines with oxygen to form water vapor as its only waste product.
However, since pure hydrogen gas can't be found in abundance on Earth, it's usually manufactured from unlocking other compounds, many of which are nonrenewable sources such as coal and natural gas. That antimony-gallium nitride alloy can be used to convert solar energy into an affordable, carbon-free source for hydrogen is incredibly impressive, the researchers said.
Once this alloy material is widely available, it could conceivably be used to make zero-emissions fuel for powering homes and cars and to heat homes, said Mahendra Sunkara, a professor at the University of Louisville Conn Center for Renewable Energy Research.