Artificial Leaf Is 10 Times Better at Generating Hydrogen From Sunlight
A “hydrogen economy” sounds just about as green and eco-friendly as it gets. Fuel cells that combine hydrogen with ambient oxygen in the air can generate electricity with naught but pure water as a byproduct—which is great if you hate pollution and are thirsty. The problem we face now is the source of our hydrogen: the vast majority of it comes from fossil fuels, specifically natural gas. And while transforming methane into hydrogen is 80 percent efficient, that other 20 percent is carbon dioxide.
The vast majority of the accessible clean hydrogen on Earth is locked up with oxygen in water, but breaking apart H2O into an O and a useful H or two isn’t a particularly environmentally-friendly or efficient process to get involved in. The fantasy is an “artificial leaf,” a passive, inexpensive thing that you can stick in water and expose to sunlight, then watch as it bubbles off all the hydrogen and oxygen you need. People have been working on these, but Caltech has just made an enormous amount of progress with an artificial leaf that, according to the researchers, “shatters all of the combined safety, performance, and stability records for artificial leaf technology by factors of 5 to 10 or more.”
Caltech’s Joint Center for Artificial Photosynthesis has been working on ways of turning sunlight, water, and CO2 into useful chemical fuels for the last half decade. They’ve just published a paper in Energy and Environmental Science describing a new design that’s efficient, simple, relatively inexpensive, and reliable enough to suggest a path towards industrialization.
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