Dual BN quantum dot/Ag co-catalysts synergistically promote electron-hole separation on g-C3N4 nanosheets for efficient antibiotics oxidation and Cr(VI) reduction

Abstract

The urgent challenge of semiconductor photocatalysis technology is to prevent the rapid recombination of photogenerated electron-hole pairs on the basis of making full use of solar energy. Fortunately, the co-catalysts usually play a non-negligible role in achieving high photocatalytic performance. Herein, BN quantum dots (BNQDs) and Ag as novel dual co-catalysts are introduced on g-C3N4 (CN) nanosheets that could transfer carriers rapidly in a large area, boosting the photocatalytic performance of CN. Specifically, Ag is a bright choice for improving solar energy utilization and serving as electron sinks, while BNQDs could act as superior photoinduced-hole extractors. The photogenerated electron-hole pairs are finally pulled apart due to the synergistic effect of the dual co-catalysts, stimulating a large number of photogenerated electrons and holes to participate in their respective redox reactions efficiently. In consequence, the CN/Ag/BNQDs(3) ternary composites exhibit stronger oxidizing and reducing properties, which are reflected in the oxidative degradation efficiency of TC (80.54%) and the ability to reduce Cr(Ⅵ) (88.93%) within 60 min were 3.04 and 10.03 times than pure CN. This research paves a path for the design of photocatalysts with high-efficiency carrier separation capabilities, and broadens the way for the application of co-catalysts in the field of photocatalysis.