Transition metal bismuth spheres dispersed and anchored in benzene-ring-grafted porous g-C3N4 nanosheets for photocatalytic reduction of CO2

Abstract

Graphitic carbon nitride (g-C3N4) holds a prominent position in the field of photocatalysis and represents one of the most promising non-metallic catalysts at present. However, its inherent defects undermine its photocatalytic activity, thus limiting its practical applications. To address this issue, we employed transition metal bismuth spheres, which were dispersed and anchored on benzene-ring-grafted porous g-C3N4 nanosheets, for the photocatalytic reduction of CO2 via a simple solvothermal synthesis method. The experimental results revealed that Bi-BCN-0.2 exhibited the highest photocatalytic CO2 reduction, yielding 8.17 μmol/(g·h) of CO, which was 21 times greater than CN (0.39 μmol/(g·h)) and 8.5 times greater than BCN (0.95 μmol/(g·h)). Through relevant characterization, we found that the introduction of benzene rings in the CN skeleton resulted in an expansion of π-electron delocalization, leading to improved the efficiency of charge separation upon photoexcitation. Additionally, the further loading of Bi sphere co-catalysts, forming Schottky junctions, effectively inhibited the recombination of photogenerated electron-hole pairs and promoted photogenerated charge transfer. Furthermore, the SPR (surface plasmon resonance) effect enhanced the light harvesting ability. These modifications collectively contributed to enhancing the photocatalytic activity of g-C3N4 and introduced a novel approach for utilizing g-C3N4 in the photocatalytic reduction of CO2.