Bi-doped CuCeO2−x nanorod catalysts for photothermal CO-PROX in H2-rich streams: Enhanced oxygen vacancy and light absorption capacity

Abstract

The wide band gap of ceria limited the light absorption and photothermal conversion of copper-ceria catalyst for photothermal preferential oxidation of CO (CO-PROX). In the present work, doping Bi element was adopted to regulate the energy band and catalytic performance of CuCeO2−x nanorod catalysts for photothermal CO-PROX. Bi/CuCeO2−x nanorods were synthesized by co-precipitation hydrothermal and deposition precipitation method. The Bi/CuCeO2−x catalyst with the molar ratio of Bi/Ce 2.5% exhibited the best catalytic performance and the CO conversion reached 90% under 2.5 suns with a surface temperature of 120 °C. The doped Bi species were incorporated into the CeO2 lattice and promoted the formation of oxygen vacancy sites and the strong Cu-Ce interaction, as revealed by XRD, XPS, Raman and H2-TPR results. In addition, doping Bi reduced the band gap of ceria nanorod from 2.77 to 2.47 eV and remarkably enhanced the UV–vis light response and photogenerated carrier separation of Bi/CuCeO2−x-2.5.