An economy based on hydrogen fuels - which only emit water - could soon be a reality

Hydrogen is the most abundant element in the universe, so it only seems natural that hydrogen fuels have been touted by many as the solution to our future energy needs, especially given that the only thing they emit when burnt is water.

However, extracting hydrogen fuel from sources such as water or fossil fuels on a large scale is very difficult, requiring large amounts of energy, not to mention other limiting factors.

Turning water into hydrogen fuel using solar energy could make the process viable, but currently, this relies on photocatalysts containing expensive precious metals, limiting its capacity.

Now though, researchers from Osaka University have developed a new kind of photocatalyst for extracting hydrogen from water that is free of expensive metals and also absorbs a wider range of sunlight than ever before. Their findings are presented in the Journal of the American Chemical Society.

"We were pleased to find a good amount of hydrogen produced from water using our new composite photocatalyst with graphitic carbon nitride and black phosphorous," Tetsuro Majima, the lead author of the study, said. "But what we didn't expect to find was that even when using low-energy light, in the near infrared, the photocatalyst continued to produce hydrogen."

Previous photocatalysts based on carbon nitride have needed to be combined with precious metals to be able to extract hydrogen from water. However, in the new study the researchers found that this metal could be replaced with phosphorous – an abundant and inexpensive element.

In addition, they found that their photocatalyst could drive hydrogen production in a whole range of light conditions, even working in low-energy near-infrared light.

"The hydrogen economy faces a great many challenges, but our work demonstrates the potential for efficiently and cheaply producing hydrogen from water with a photocatalyst based on widely abundant elements," Majima said. "This is an important step toward making other hydrogen-based technologies economically and environmentally viable."