Bringing down the cost of the artificial leaf


A plant’s leaf is the most efficient way of turning sunlight into energy through photosynthesis and scientists have been striving to replicate this using artificial leaves as fuel cells, generating electricity through a chemical reaction with oxygen or another oxidising agent.

One of the obstacles to artificial photosynthesis is the expensive platinum catalyst required, however a team at Massachusetts Institute of Technology (MIT) led by Danial Norcera says his team has found a way to replace it with a cheap nickel-molybdenum-zinc compound. This puts him one step closer to his goal of finding an inexpensive, portable source of renewable energy for developing countries.

Artificial leaves resemble a thin playing card, described by MIT as a “silicon solar cell with different catalytic materials bonded onto its two sides”. Covered with water and placed in sunlight, it splits hydrogen and water, mimicking photosynthesis.

In a real leaf, the hydrogen is then combined with CO2 from the atmosphere to make sugars, cell walls and other organic matter. In the artificial version, scientists use the hydrogen in fuel cells to make electricity or else combine it with CO2 to make fuels such as methanol. This could be used in car engines, much as ethanol biofuels are used today and would provide a carbon-neutral source of power.

“I’ve got to say that the Norcera system is very good – it’s probably at the moment the best in the world, but there are other alternative approaches and many places are working on it,” said Jim Barber, a biologist at Imperial College London.

Barber is part of another team researching artificial photosynthesis. His project uses iron oxide, or rust, as a cheap material to absorb light and serve as a semi-conductor. “The sun is the only energy source available to us of sufficient magnitude to satisfy our needs. That’s why it’s so important to continue to develop the research and development. The Nocera work is a giant leap forward towards this goal of capturing sunlight and storing it as a fuel,” Barber explained.

Artificial leaves would also fill some of the gaps left by other renewable energy technology. They could be used in arid regions where hydropower is unfeasible, they take up less space than solar panels and don’t require a battery to store energy.

According to Barber, if artificial photosynthesis systems could use around 10% of the sunlight falling on them, they would only need to cover 0.16% of the Earth’s surface to satisfy a global energy consumption rate of 20 terawatts, the amount it is predicted that the world will need in 2030.

See the original article here: Scientists find a way to bring down cost of producing ‘artificial leaf’

See related article here: Artificial leaf could generate fuel by photosynthesis

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