Enhanced photoelectric performance of rutile SnO2 by Mg-assisted S-O coupling

Abstract The electronic structures and conducting mechanism of (Mg, S) co-doped rutile SnO 2 were explored through density functional theory (DFT) calculation. Results showed that the acceptor metal Mg assisted the coupling of the incorporated S with a neighbouring O in SnO 2 , which introduced new energy levels into the forbidden band of SnO 2 and thereby improved the photoelectric performance of SnO 2 . Based on this result, we proposed an integrated strategy that combines DFT calculations with experiments to study the photoelectric performance of (Mg, S) co-doped SnO 2 prepared through hydrothermal method. Conducting glass (FTO) was used for the preparation of (Mg, S) co-doped SnO 2 electrode. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and ultraviolet–visible diffuse reflectance spectroscopy results confirmed the incorporation of Mg and S elements into the SnO 2 cell. Furthermore, photoelectric performance tests revealed that (Mg, S) co-doping can improve photoelectric performance. The maximum photocurrent (0.50 μA/cm 2 ) and smallest impedance were obtained at a co-doping ratio of 5%. Therefore, the (Mg, S) co-doped SnO 2 is a strong candidate for photoelectrocatalysis.