SnO2/SnS2 heterojunction with mesoporous structure for improved photocatalytic degradation of sulfonamide antibiotics

Abstract The SnO2/SnS2 composite photocatalyst with mesoporous structure and S-type heterojunction was successfully constructed, and their photocatalytic degradation activity under visible light irradiation was investigated using sulfonamide antibiotics as the target degradants. The results show that SnO2/SnS2 obtained by hydrothermal reaction at 180°C presents a flower ball with a size of about 5μm, a relatively high specific surface area of 50 m2g-1 and a large mesoporous pore size of 12.33 nm, and has lower fluorescence intensity, stronger stability and more abundant active sites. It is worth noting that SnO2/SnS2 has a strong light response at the wavelength of 200-800nm, and degradation rate of SnO2/SnS2 was 1.7 times that of SnO2 and 1.5 times that of SnS2, after photocatalytic reaction time of 210 min, respectively. It is benefitting from that the S-type heterojunction structure formed by the coupling of mesoporous SnO2 and SnS2 has a synergistic effect, which reduces the band gap and improves the photocatalytic activity. It can be seen that the photocatalytic degradation of sulfonamides by SnO2/SnS2 belongs to the zero-order reaction, and the reaction rate constant increases with the increase of temperature.