G-C3N4 modified La0.01Sr0.99Ti0.99Cr0.01O3 for efficiently visible-light-driven photocatalytic water treatment

Abstract

Water pollution caused by pharmaceutical wastewater has received increasing attention, and photocatalysis is a potential method to solve this problem. In this article, La and Cr co-doped SrTiO3 was prepared by electrospinning method, and was mixed with g-C3N4 to prepare La0.01Sr0.99Ti0.99Cr0.01O3/g-C3N4 (STO-1/CN) composite photocatalyst. The synthesized photocatalyst was characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and UV visible diffuse reflectance spectroscopy. The optimized STO-1/CN performs enhanced absorption of visible light, and separation and migration of carriers become more effective, which contributes to improve photocatalytic performance of STO-1/CN composites. The maximum photocatalytic activity, 0.0055 min−1 was obtained by heterojunction containing 50 wt% g-C3N4 (STO-50CN) in degrading CI under visible light, which was 4 and 2 times that of pure g-C3N4 and La0.01Sr0.99Ti0.99Cr0.01O3, respectively. The active species capture experiments indicate that the photocatalytic degradation of CI by composite photocatalysts is the result of the combined action of h+ and ·O2-. Based on the above conclusions, a possible mechanism of La0.01Sr0.99Ti0.99Cr0.01O3/g-C3N4 photocatalytic degradation of CI is proposed.