Poly(heptazine imide) with Enlarged Interlayers Spacing for Efficient Photocatalytic NO Decomposition

Sluggish charge kinetics and NO diffusion largely restrict the photocatalytic efficiency of low-dose NO removal by layered carbon nitride (CN). Herein, a novel poly(heptazine imide)-based CN (CN-NaLi) with enlarged interlayer spacing was fabricated by an easy, efficient and unique molten-salt approach. The charge flows induced by the poly(heptazine imide) structure can be delocalized/separated/transferred, resulting in a significantly boosted efficiency of charge kinetics. The enlarged interlayers distance of CN-NaLi reduced the charge-recombination probability and promoted NO diffusion/adsorption/activation. Accordingly, abundant separated light-induced electrons can be supplied to react and activate the O2 molecules. Meanwhile, large amounts of adsorbed NO were fixed and converted into the intermediate product during the same time compared with unmodified CN. The reduced energy barrier endowed CN-NaLi with superior visible-light-driven performance, high stability, and decreased generation of toxic products in NO purification. This research highlighted the vital concerns in affecting the interlayer NO diffusion/adsorption/activation and charge delocalization/separation/transportation.