Efficient photocatalytic fixation of N2 by KOH-treated g-C3N4

Abstract

Development of N₂ photofixation under mild conditions is challenging; one reason for low efficiency is the poor reactivity between water and photocatalysts. Herein, C₃N₄ after KOH etching was used as an efficient photocatalyst, and CH₃OH was first introduced as a proton source. The photocatalyst presented a high ammonia evolution rate of 3.632 mmol g⁻¹ h⁻¹ and achieved an apparent quantum yield of 21.5% at ∼420 nm. In addition to the role of reacting with holes to accelerate the production and transfer of electrons, CH₃OH also promoted the solubility of N₂ and provided a proton to the activated N₂. The CH₃OH system should be instructive for a better understanding of proton-enhanced photocatalysis.