Boosting visible-light-driven photocatalytic performance of waxberry-like CeO2 by samarium doping and silver QDs anchoring

Abstract

In this work, waxberry-like CeO2 photocatalyst (denoted ASC) with prominent visible-light-driven photocatalytic performances for multi-model reactions was achieved by Sm doping and Ag quantum dots (QDs) anchoring. For instance, the as-fabricated ASC acquired 7.08-times and 6.83-times higher activities for CH3CHO removal and H2 production than those of pure CeO2 counterpart, respectively. The concentration of oxygen vacancies (Ov) in CeO2 is distinctly increased by Sm doping, resulting in a narrower bandgap of the Sm-doped CeO2 (SC). Under visible light irradiation, the Ov caused by doping can capture the photo-excited electrons and construct a doping-related transition state between the conduction band (CB) and the valence band (VB), which can effectively limit the recombination of photo-excited electrons and holes. These captured electrons further fleetly transfer to the co-catalytic sites of anchored Ag QDs, strengthening the absorption utilization for visible-light synchronously. The migration of charge carriers and proposed mechanisms were well elaborated by transient photovoltage (TPV), surface photovoltage (SPV) and density functional theory (DFT) calculation. It is hoped our work in this paper could provide potential and meaningful strategies for the design of noble metal quantum dots modified metal oxide semiconductors and facilitate their applications in other photocatalytic fields effectively.