Enriching CO₂ Activation Sites on Graphitic Carbon Nitride with Simultaneous Introduction of Electron-Transfer Promoters for Superior Photocatalytic CO₂-to-Fuel Conversion

Limited CO₂ adsorption and inefficient charge transfer of graphitic carbon nitride (g-C₃N₄) have been the two major obstacles for its application in photocatalytic CO₂ reduction. In this work, a new type of carbon nitride photocatalyst (K-incorporated amino-rich carbon nitride, K-AUCN) is designed and prepared by a facile posttreatment of urea-polymerized g-C₃N₄ (UCN) using KOH as a chemical activation agent. The resultant K-AUCN has not only enriched intrinsic amino groups for superior CO₂ adsorption, but also incorporated potassium and carbon defects as electron promoters for efficient photocatalytic reduction of CO₂ in the presence of water vapor. Compared to UCN, the photocatalytic CO₂ conversion performance on K-AUCN is drastically promoted by five folds with 7.7-time increase in CO₂ adsorption. This work not only presents a simple design of low-cost photocatalyst for CO₂ reduction with enhanced performance, but shall also inspire more rational design of efficient catalysts for photocatalytic reduction of CO₂ and other specific photocatalytic reactions.