Photocorrosion inhibition and high-efficiency photoactivity of porous g-C3N4/Ag2CrO4 composites by simple microemulsion-assisted co-precipitation method

A facile microemulsion-assisted co-precipitation method was carried out to synthesize nano-sized Ag 2 CrO 4 highly dispersed on the surface of porous g-C 3 N 4 as high-efficiency visible-light-driven composite photocatalysts for the first time. The structure and morphology of the composites were systematically characterized by various techniques. Compared with Ag 2 CrO 4 and g-C 3 N 4 , g-C 3 N 4 /Ag 2 CrO 4 composites showed a dramatically increased photocatalytic activity in degradation of rhodamine B (RhB) and methylene blue (MB). The optimum mass ratio of the Ag 2 CrO 4 to g-C 3 N 4 was about 30   wt%, the degradation rate of which were 6.1 (7.9) and 9.7 (15.2) times higher than pure Ag 2 CrO 4 and g-C 3 N 4 in RhB (MB) degradation, respectively. The excellent photocatalytic activity and stability mainly benefited from the synergistic effect including smaller Ag 2 CrO 4 particle size, high specific surface area of the composites and matched band potentials which not only promoted the separation of photon-generated charge carriers, but also inhibited the photocorrosion of Ag 2 CrO 4 . Further study revealed that the photocatalytic mechanism followed a Z-scheme which provided an efficient transfer pathway for charge carriers meanwhile endowed the composites with strong oxidation and reduction ability. Hence the porous g-C 3 N 4 /Ag 2 CrO 4 composites are potential in environmental purification.