Steering oxygen vacancies for the enhanced photocatalytic degradations of dyes and tetracycline over Cu, Yb co-doped SnO2 with efficient charge separation and transfer

The antibiotic and dyes disposals are the promising strategy for the persistent environmental problems. For the photocatalytic process, charge separation and transfer are the key issue, in which its rate should be faster than that of the recombination to participate into the chemical reactions. In this work, we exploited the Cu, Yb co-doped SnO2 via one-step hydrothermal method. The enhanced charge transfer rate was characterized by XPS, photocurrent, electrochemical impedance spectra, photoluminescence and EPR measurements. Benefiting from higher charge transfer rate, co-doping of Cu and Yb into SnO2 could achieve superior photocatalytic activities for the degradations of dyes and tetracycline. The result confirmed that the introductions of Cu and Yb could redistribute the photo-induced carriers on the surface of SnO2. In addition, the photogenerated electrons were captured by the defective sites, and thus it facilitated the efficient charge transfer over SnO2.