This Light-Powered Catalyst Can Make Profitable Hydrogen From A Stinky Waste Gas

Hydrogen sulfide is notorious for having a deplorable smell. Also, it’s toxic, corrosive, flammable, and produced in abundance. Now, researchers have found an easy, profitable way to turn it into hydrogen.

Currently, the way that is being used to treat its stinky smell is that to heat it up with air to between 800-1,100 °C (1,470-2,000 °F), then run it through a series of condensers, reheaters, and catalytic reactors to convert it into sulfur and water. This is called the Claus Process. This method eats up a great chunk of energy.

Researchers at Rice University say they can eliminate that energy use and its associated emissions, while still recovering the sulfur and acquiring useful hydrogen gas to boot.

They use a nano-engineered silicon dioxide powder catalyst, each grain speckled with nanoparticles of gold just billionths of a meter wide. These gold particles respond strongly to a specific wavelength of visible light, giving off short-lived electrons called “hot carriers.” These electrons carry enough energy to split H2S molecules into H2 and S to be acquired separately.

The process can completely function on solar energy. It will work with the same efficiency on artificial light as well.

“Hydrogen sulfide emissions can result in hefty fines for industry, but remediation is also very expensive,” said Naomi Halas, lead author of the study and co-founder of Syzygy Plasmonics, which has licensed the new technology for commercialization. “The phrase ‘game-changer’ is overused, but in this case, it applies. Implementing plasmonic photocatalysis should be far less expensive than traditional remediation, and it has the added potential of transforming a costly burden into an increasingly valuable commodity.”

The process should be reducing carbon emissions. However, due to the sizeable amount of energy used in the refining process, it seems unlikely that the hydrogen made will be eligible for the “green” classification, since it is being derived from fossil fuel.

The study is available in the journal ACS Energy Letters.

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