New Photocatalyst Could Revolutionize Green Hydrogen And Ammonia

The field of photocatalysis chemistry is producing important breakthroughs in industrial chemistry. In July, LightNOW reported on a new photocatalyst revolutionizing the conversion of methane into liquid methanol, here. Now Rice University researchers have created a small, LED-powered device that converts ammonia to hydrogen on the fly

Image: Rice University. Syzygy’s LED-powered photoreactors and Rice University’s extraordinarily effective nanoengineered photocatalysts promise an environmentally critical revolution in industrial chemistry.

Ammonia might carry hydrogen exceptionally well, but if you want to use that hydrogen, you need to “crack” it to get the hydrogen out and release the harmless nitrogen back into the atmosphere. This has been difficult for two main reasons: firstly, the reaction is endothermic, so most ammonia cracking is done in large facilities operating at temperatures of at least 650-1,000 °C (1,200-1,800 °F). Secondly, the thermal catalysts required for the cracking operations are typically platinum-group metals like ruthenium – relatively rare and expensive.

The breakthrough utilizes “antenna-reactor” plasmonic photocatalysts. These are nanoparticles of a catalyst, dotted with little clumps of an “antenna” material designed to increase the catalyst’s ability to absorb light. Properly tuned, these antenna-reactor particles take in energy from ambient light – be it sunlight, or light from low-energy LEDs – and kick out short-lived “hot electrons” with enough energy to start an efficient chemical reaction even at ambient temperatures.

This ammonia-splitting photocatalyst uses iron as its reactor, and copper as its light-collecting antenna – both cheap and abundant metals, as opposed to the typical copper-ruthenium thermal catalysts used today. This copper-iron photocatalyst should make it much cheaper and easier to extract hydrogen from ammonia. But it’ll also do it without needing heat, so there’ll be energy and emissions saved as well.

LED lighting will become an industrial input to this process, creating a new category of lights for industrial chemistry. The full story can be read here.

Image: Syzygy’s Plasmonics. Syzygy’s Rigel photocatalytic reactor is about the size of a washing machine (right), and it can be deployed in banks (left).

David Shiller

David Shiller is the Publisher of LightNOW, and Senior Business Development Consultant at Capacity Consulting, a North American consulting firm providing business development services to advanced lighting manufacturers. The ALA awarded David the Pillar of the Industry Award. David has been co-chair of the ALA’s Engineering Committee since 2010. David established MaxLite’s OEM component sales into a multi-million dollar division. He invented GU24 lamps while leading ENERGY STAR lighting programs for the US EPA. David has been published in leading lighting publications, including LD+A, enLIGHTenment Magazine, LEDs Magazine, and more.

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