Improved performance of Zn-doped SnO2 modified g-C3N4 for visible light-driven photocatalysis.

Abstract

The low-cost composite of g-C3N4 modified by Zn-doped SnO2 nanoparticles was prepared for the first time in this work. The characterization results of XRD and SEM demonstrated that Zn was successfully doped into SnO2. The formed Sn-O-Zn bonds and interaction between the Zn-doped SnO2 sample and g-C3N4 in the composite were explored by FT-IR and XPS technologies. Photocatalytic degradation experiments showed that the as-prepared optimal composite photocatalyst displayed enhanced photocatalytic reactivity towards both dyes and antibiotics, which could degrade 85.6% of RhB and 86.8% of tetracycline within 30 and 90 min, respectively. The oxygen vacancies formed in SnO2 after Zn doping could capture the photogenerated electrons of g-C3N4, thereby promoting the separation of photogenerated electron-hole pairs, then more ·O2- and holes can be generated during the visible light-driven photocatalytic reaction, so that the composite of Zn-doped SnO2/g-C3N4 acquired higher photocatalytic activity and accelerated the degradation of target organics. Active species capturing experiments and ESR detection results also confirmed that ·O2- and holes were the main active species in the reaction process. This work developed a novel g-C3N4-based photocatalyst with no noble metal, low price, and high photocatalytic activity, which could provide a cost-effective and high-efficiency strategy for wastewater treatment.