Electrostatic promotion of the catalyst activity for ammonia photosynthesis upon a robust affordable nanostructured uni-electrodic photodevice/reactor

Abstract

Nitrogen photo-fixation, under ambient conditions using low-price, earth-abundant, and eco-friendly nanostructured solar-energy materials and water feedstock, is a sustainable strategy to produce ammonia—a modern, safe, green, and H-based fuel as well as principal nitrogen supply for living organisms. To this end, herein, the authors fabricated a robust, stand-alone FeS₂/Cu monolithic photoelectrochemical device, which is able to continually photosynthesize ammonia while N₂ molecules reaching the photodevice surface. Furthermore, it is reported for the first time that without consuming electricity [electron flow; faradaic process], just by applying a non-faradic/electrostatic potential bias to the device or adding a promoter species into the reaction medium, the activity of the photodevice to synthesize ammonia can be substantially enhanced [promotion: up to ∼131%]. Finally, through a photoelectrochemical approach and providing extra supporting evidence, the phenomenon is interpreted in detail from basic viewpoints.