Novel Au@C modified g-C3N4 (Au@C/g-C3N4) as efficient visible-light photocatalyst for toxic organic pollutant degradation: Synthesis, performance and mechanism insight

Abstract

Tailoring economical g-C3N4-based composites with efficient visible-light photocatalytic degradation ability have received great attention. In this study, a novel and efficient visible-light photocatalyst, Au nanoparticles doped porous carbon modified g-C3N4 (Au@C/g-C3N4), was synthesized using thermal polycondensation method. The crystal, morphological and photoelectrical characterizations verified the successful synthesis of Au@C/g-C3N4 hybrid and it had larger specific area and narrower band gap than that of pure g-C3N4. The optimal Rhodamine B (RhB) photocatalytic oxidation performance (94.3%) and mineralization rate (50.7%) were obtained by Au@C/g-C3N4-2 composite at 1.0 g L−1 catalyst dosage and pH of 5.0, which was 3.23 and 2.96 times, respectively than that of g-C3N4 at the same conditions. Au@C/g-C3N4-2 also maintained satisfactory RhB degradation efficiency (70.7%) after 4 consecutive photocatalytic cycles. Mechanism analyses indicated that the significantly improved photocatalytic activity of Au@C/g-C3N4 composite mainly attributed to the rapid separation and migration of charge carriers via the interfacial interaction between the Au@C and g-C3N4, which resulted in the accelerated O2− generation for organic pollutants oxidation. In general, this study supplied a novel strategy for efficient g-C3N4 visible-light photocatalysts construction, and further clarified its plausible visible-light photocatalytic mechanism.