Barrier to harnessing solar energy broken

Washington, August 1:

Researchers have found a new way to store solar power, a major breakthrough in the search to use the sun and serve the Earth’s energy needs in a clean and sustainable way.

Every hour, the sun gives off enough radiation to serve the Earth’s energy needs for a year. The trouble is how to store it cheaply and use it whenever needed.

Daniel Nocera and Matthew Kanan of the Massachussets Institute of Technology (MIT) have developed a process that will use the sun’s energy to split water into hydrogen and oxygen gases. Later, oxygen and hydrogen are recombined inside a fuel cell, creating carbon-free electricity.

The theory was known, but splitting had been enormously expensive and grossly inefficient till they showed the way. The key component in their process is a new catalyst that produces oxygen from water; another catalyst produces hydrogen. The new catalyst consists of cobalt, phosphate and an electrode, placed in water. When electricity — from any source — runs through the electrode, cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced.

Combined with another catalyst, such as platinum, that can produce hydrogen gas from water, the system can duplicate the water-splitting reaction that occurs during photosynthesis.

The new catalyst works at room temperature, in water that is neither acidic nor alkaline, and it’s easy to set up, Nocera said. “That’s why I know this is going to work. It’s so easy to implement. This is the nirvana of what we’ve been talking about for years,” said Nocera, professor of energy at MIT. “Solar power has always been a limited, far-off solution. Now we can seriously think about solar power as unlimited and soon.” Earlier electrolysers that split water with electricity and are often used industrially are not suited for artificial photosynthesis because they are very expensive and require a highly alkaline environment.

James Barber, a leader in the study of photosynthesis who was not involved in this research, called the discovery by Nocera and Kanan a “giant leap” toward generating clean, carbon-free energy on a massive scale.

“This is a major discovery with enormous implications for the future prosperity of mankind,” said Barber, Ernst Chain professor at Imperial College, London. “The importance of their discovery cannot be overstated since it opens up the door for developing new technologies for energy production thus reducing our dependence for fossil fuels and addressing the global climate change problem.”