In theory renewable hydrogen can be generated by photoelectrolysis. Here solar power is used to split water molecules into oxygen and hydrogen. However, to operate this on a commercially sustainable scale certain inefficiencies need to be overcome, not least energy loss. The lead researcher, in relation to the new development, Dr Manus Hayne summarizes this: “For research to progress, innovation in both materials development and device design is clearly needed.”
In new research, scientists have shown how the use of nanostructures can increase the maximum photovoltage generated in a photoelectrochemical cell. This serves to ramp up the energy productivity from splitting water molecules. Dr Hayne explains further: “This system has never been investigated either theoretically or experimentally, and there is huge scope for further work to expand upon the results presented here.”
The main advantage of investing in hydrogen power is to reduce fossil-fuel combustion. The process of burning fossil fuels releases carbon dioxide into the atmosphere, triggering climate change (greenhouse gases in the atmosphere ‘capture’ some of heat emitted from the Earth, then re-emit it in all directions, including back to the Earth’s surface). In addition, the world’s supply of fossil fuels is dwindling. This means human society needs to transition to a renewable and low-greenhouse-gas energy infrastructure. A step towards this vision involves ‘clean’ technologies like renewable hydrogen.
Central to this are photovoltaic solar cells (where there is the creation of voltage or electric current in a material upon exposure to light). These are widely used to convert sunlight directly into electricity. A more efficient use of these cells is with solar hydrogen, which can be easily stored. A further advantage is that hydrogen is flexible, and this makes it very suitable for remote communities. Here hydrogen can be converted to electricity in a fuel cell, or burnt in a boiler or cooker just like natural gas. This opens up a number of business opportunities, especially for start-up technology firms.
Hydrogen power uses a zero-emission fuel when burned with oxygen, based on electrochemical cell technology.
The new research has been published in the journal Scientific Reports, under the heading “Photoelectrolysis Using Type-II Semiconductor Heterojunctions.”
