Terminal p-π conjugation induced excited-state symmetry-breaking charge separation for porous carbon nitride based heterojunction

Abstract

To reach the purpose of high photocatalytic property, efficient charge separation is needed. Own to the low crystalline and two dimensional characters, it is rather harder to obtain the photoinduced charge transferring information for g-C3N4 than faceted crystal materials. Herein, images for distributions of photoinduced electrons and holes were utilized to analyze the excited-state characteristics and charge transfer directions. Both the theoretical calculation and experimental results reveal that the riched terminal NHx p-π conjugation groups for defect porous carbon nitride (PCN) destroy the symmetry of intrinsic g-C3N4 (CN), which results in a spatial asymmetry distribution of photoinduced electrons and holes, and enhanced photocatalytic activity. To further improve PCN activity, a novel ternary Ni2P/Zn0.2Cd0.8S/PCN photocatalyst was constructed and the H2 evolution rate was 3.04 times of PCN. The enhanced H2 generation performance is attributed to NHx groups hydrogen bond induced well-connection in the ternary Ni2P/Zn0.2Cd0.8S/PCN heterojunction photocatalysts.