Nanoarchitectonics of g-C3N4 Nanosheets with a AuCu Enhancement Effect for Superior Photo- and Electrochemical Activity

AuCu alloy nanoparticles (NPs) were embedded in superior thin g-C3N4 nanosheets by a mechanochemical pre-reaction and subsequent thermal polymerization at high temperature. The introduction of AuCu NPs increased conductivity, decreased the band gap, expended light absorption, and improved the separation and transfer efficiencies of photogenerated electrons and holes. Moreover, the uniform distribution of AuCu NPs in g-C3N4 nanosheets is ascribed to the pre-reaction of bulk g-C3N4 and metal salts to create activity cites. The adsorption ability in the visible light region was improved due to the plasma effect of Au. AuCu/g-C3N4 composites (AuCu/CN-1%) with optimized component ratios revealed the highest transient photocurrent responses, the lowest electrochemical impedance arc radius, and the best photocatalytic H2 evolution rate of 930.2 μmol g-1 h-1. These findings exhibited that loading AuCu bimetallic NPs could efficiently offset some disadvantages of g-C3N4 and improve its photocatalytic performances.