Co-doping g-C3N4 with P and Mo for efficient photocatalytic tetracycline degradation under visible light

Abstract

Although g-C 3 N 4 (CN) materials have been extensively explored for the photocatalytic degradation of organic pollutants, their weak response to visible light and fast recombination of photoexcited electron-hole pairs restrain their practical applications. Herein, we deeply mediated the CN's energy-band structure, morphology, and surface properties by non-metal (P) and metal (Mo) co-doping based on the thermal treatment of a phosphomolybdic acid hydrate and dicyandiamide mixture in a straightforward one-step manner. Meanwhile, cyano groups and nitrogen vacancies were generated as a result of the co-doping, and the resulting P, Mo co-doped CN (PM-CN) exhibited thinner layers, smaller sizes, and superior visible-light harvesting capacity and charge separation efficiency. Consequently, highly active PM-CN was obtained for photocatalytic tetracyclines (TC) degradation, and the rate was calculated to be 0.01 min −1 , 3.3 times greater than that of the pure CN, outstripping the single P- and Mo-doped counterparts. A free radical scavenging test demonstrated that the reactive species •O 2− and h + were critical in TC degradation. The present work is expected to shed light on co-doping CN with non-metal and metal elements to obtain high-performance, visible-light-responsive photocatalysts for practical environmental remediation.