Atomic-level active sites steering in ultrathin photocatalysts to trigger high efficiency nitrogen fixation

Abstract

Photocatalytic nitrogen fixation is an attractive pathway to produce ammonia, which is an important industrial raw material for fertilisers, chemicals and energy, but still suffers from low conversion efficiency. By virtue of unique electronic structures and unusual physicochemical properties, significant research efforts regarding ultrathin photocatalysts have been made to show excellent nitrogen fixation behavior. In this review, state-of-the-art progress of ultrathin structured N2 fixation photocatalysts is reviewed, with the emphasis on atomic-level active sites tuning to affect the N2 fixation performance. We begin with the basic understanding on photocatalytic N2 fixation along with some key matters need attention in the N2 fixation experiments. Then, the ravishing roles of ultrathin thickness in photocatalysis for adjusting light absorption, charge-transfer dynamics, and surface N2 fixation reactions will be demonstrated. Diverse strategies have been presented to elucidate the tuning of fine geometric and electronic structures of various active sites in ultrathin photocatalysts towards N2 fixation reaction. Finally, we end this review with a look into the future opportunities and challenges of ultrathin photocatalysts for nitrogen fixation.