Future fuel quest takes a step forward…..

A team of Scottish-based scientists has developed a new technique for creating hydrogen fuel.

Working at Heriot-Watt University, they’ve created a system that uses sunlight to create hydrogen more cheaply and efficiently than before. Hydrogen is the lightest element in the Universe. A gas at room temperature, it burns with oxygen to give off heat and water vapour.

Unlike carbon-based fossil fuels, there is no carbon dioxide to add to the planet’s climate concerns. It is that feature which has made it a prime candidate to be a major part of our future energy supplies.

But before what has already been dubbed the “hydrogen economy” can fully develop, it first has to be economical.

Hydrogen can be produced using fossil fuels, which adds to CO2 emissions.

Another, cleaner method appears simple: harvest energy from the sun using solar cells, then pass the resulting electricity through water. The water splits cleanly into hydrogen and oxygen.

It’s called PEC – photoelectrochemical water splitting.

So far, so simple-sounding. But it is not particularly efficient. It costs twice as much to produce as energy from wind and biomass because you have to put a lot of energy in to get the hydrogen out.

One method of improving efficiency is to put the two electrodes into fluids with different values of pH – one acidic, one alkaline. But they must be kept apart by a membrane and that brings further problems.

Now Dr Jin Xuan has developed a new type of PEC cell which he says “will use cheap, widely available materials that mean the technology can be easily scaled up to meet the growing demand for hydrogen fuel”.

Before now, energy of at least 1.23 electron volts (eV) was needed to split the water. The new device has lowered that to just 0.35 eV.

“We have already proved that this system has potential,” Dr Xuan says.

“We’ve applied a similar design strategy in a number of energy devices, such as fuel cells and batteries.”

There are still many hurdles to be overcome before hydrogen fuelled trains and cars become commonplace. One – almost literally – burning issue is the safest way to store large quantities of highly flammable gas.

Heriot-Watt’s reactor design is itself still in the laboratory. It will take more work before it can be scaled up and brought to market.

But Dr Xuan is already thinking about one specific way in which it could be used.

“My home is now in Juniper Green. It’s a small village near the university,” he says.

“If you can install centralised fuel cells there you can generate heat and electricity to power the whole community.

“I think our device will one day achieve this target.”

What may one day work in Juniper Green could also work worldwide.

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