Construction of Schottky-type Ag-loaded fiber-like carbon nitride photocatalysts for tetracycline elimination and hydrogen evolution

摘要

In this study, a series of Schottky-type Ag-loaded fiber-like carbon nitride photocatalysts (Ag/CNF) were prepared via a combination of the solvothermal method and sodium borohydride reduction. Transmission electron microscopy images revealed that Ag particles with diameters of 10-20 nm were evenly deposited on the CNF. The Ag/CNF Schottky-type composites exhibited strong photocatalytic activity for tetracycline (TC) degradation upon irradiation with visible light. The rate constant for TC degradation was enhanced approximately 23.56 and 2.97 times in the presence of the 1.2%-Ag/CNF composite as compared with bulk g-C3N4 and CNF, respectively. In addition, the Ag-CNF Schottky-type composites promoted hydrogen evolution. Free radical trap experiments and electron spin resonance results revealed that holes (h(+)) and superoxide radicals (center dot O-2(-)) were the major active species during the photocatalytic degradation. The improved photocatalytic performance was attributable to the surface plasmon resonance of Ag and the effective separation of the photogenerated charges due to the construction of Schottky junctions between Ag and the semiconductors. This work might provide a basis for the construction of carbon nitride-based Schottky-type heterojunctions for hydrogen evolution and elimination of TC from the environment.