Carbon material selection and performance enhancement mechanism for constructing highly active Ag3PO4-based hybrid photocatalysts modified with diverse carbon materials

Abstract

Hybridizing Ag3PO4 with carbon materials can effectively overcome its shortcomings of particle agglomeration and photocorrosion. However, the diversity of carbon materials makes Ag3PO4 face confusion in the selection of hybrid carbon materials. Three representative carbon materials, carbon nanotubes (MWCNTs), MOF-derived carbon (MOF-5(C)) and biochar (T-Bio), were selected to synthesize C/Ag3PO4 (C/AP) hybrid materials by facile chemical precipitation method. XRD, SEM, XPS, etc. were used to compare the differences of various carbon materials. The factors that made the difference in the photocatalytic performance of C/AP and the important role of various carbon materials were revealed. The differences in graphitization degree, morphology, structure, conductivity and surface groups of carbon materials jointly affected the crystal phase, morphology, structure, photoelectric characteristics and photocatalytic performance of C/AP, which resulted that the photocatalytic activity of C/AP presented the order of T-Bio/AP > MOF-5(C)/AP > MWCNTs/AP. T-Bio possessed obvious advantages in terms of morphology, structure and surface groups, especially persistent free radicals (PFRs) in T-Bio could promote the generation of more active species •OH and •O2-. The results showed that the carbon materials with more suitable morphology and structure for the loading and growth of Ag3PO4 particles, better adsorptivity and electron transfer performance, higher carrier trapping performance, and more favorable groups were the ideal hybrid carbon materials for Ag3PO4.