Nitrogen and sulfur co-doped CeO2 nanorods for efficient photocatalytic VOCs degradation

Abstract

Ceria and its derivatives are environmentally-friendly and sustainable photocatalysts with a strong oxygen storage/release ability, good photostability, and high cost-effectiveness. In this work, nitrogen and sulfur synchronously doped ceria (NS-CeO₂) with a regular nanorod morphology was successfully prepared, in which doping was obtained just from one precursor and by one-step calcination treatment. The photooxidation performance of acetaldehyde on NS-CeO₂ was significantly better than that on undoped ceria. As confirmed by density functional theory (DFT) calculations, the oxygen atoms exposed on the surface were partially replaced after doping with nitrogen and sulfur, resulting in the generation of new impurity level states near the Fermi level and reduction of the bandgap of NS-CeO₂. Meanwhile, the increased concentration of oxygen vacancies formed a doping transition state which can act as an effective electron capture center. In addition, this transition state further exhibits a mediation role in interfacial charge separation due to its effective restriction of the recombination of electrons and holes, which can further improve the photocatalytic performance of NS-CeO₂. Herein, an effective strategy for synthesizing non-metal doped CeO₂-based semiconductor photocatalysts that can degrade volatile organic compounds is proposed.