The free-energy cost of splitting water into hydrogen and oxygen is unavoidable. However, the price of photovoltaics has been reduced by over 99% in recent years and continues to be reduced further. Thus solar free energy can be stored as hydrogen for times when the Sun doesn't shine. The entire system can probably be designed and built with no moving parts, so that maintenance costs will be minimized. Of course there will always be some cost: all systems degrade with time and eventually need to be repaired or replaced. But this is typically more strongly true for nonrenewable energy systems than for renewable ones such as solar energy via photovoltaics, which involves no moving parts.

Osaka University-led researchers develop new metal-free photocatalyst and show visible and near infrared light-driven production of hydrogen from water.

Osaka – Hydrogen is the most abundant element in the universe, and is considered by many to be a potential clean fuel of the future. Water and fossil fuels contain large amounts of hydrogen, but unlocking molecular dihydrogen fuel from these sources takes a great deal of energy, casting doubt over any future hydrogen economy. Turning water into hydrogen using solar energy could lead the way to cheap and clean hydrogen fuel. However, this process currently relies on photocatalysts containing expensive precious metals, limiting its capacity.

Now, researchers centered at Osaka University have developed a new kind of photocatalyst for producing hydrogen from water, which is not only free of expensive metals but also absorbs a wider range of sunlight than ever before. The group recently reported their findings 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," lead author Tetsuro Majima says. "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."

Like graphite, graphitic carbon nitride forms in large sheets, but carbon nitride sheets also have holes that can interact with hydrogen molecules. In the past, photocatalysts based on carbon nitride have needed help from precious metals to produce hydrogen from water. The researchers found the metal could be replaced by a kind of phosphorus, which is a widely abundant and inexpensive element.

They showed that their photocatalyst was effective for producing hydrogen from water using energy from different kinds of light. Most unusually, even near infrared light with low energy could drive the hydrogen production.

Studies of the working photocatalyst in the picosecond time scale revealed that strong interactions between the carbon nitride and black phosphorous in the composite promoted hydrogen production. When the two materials were tested separately, energy from the sunlight was rapidly dissipated and little or no hydrogen was produced.

Lead author Tetsuro Majima says, "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. This is an important step toward making other hydrogen-based technologies economically and environmentally viable."

It will be a good to develop such technology and convert water in to oxygen and hydrogen.

Hydrogen plasma may be potential reductant to replace carbon in future but problem lies in its availability and cost.

Researchers have demonstrated high-performance electrochemical hydrogen production at a lower temperature than had been possible before.

https://www.sciencedaily.com/releases/2018/09/180904140548.htm

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Dear Lala,

There is also the H2 generation by water electrolyzer driven by the PV generated power. Every device is efficiency optimized to realize the maximum yield of the system. There is also the direct water analysis by using photoelectrochemical electrodes., which can derive autonomously the analysis process without assistance from an electrical source. This effort was within the scope of a project called Hysolar at King Saud University.

Please follow the link:Article “Basic structure of photo – electrochemical cathodes for hyd...

Best wishes

Goood subject