Impact of Pd Loading on CO2 Reduction Performance over Pd/TiO2 with H2 and H2O

Abstract

This study investigated the impact of molar ratio of CO2 to reductants H2O and H2, as well as Pd loading weight on CO2 reduction performance with Pd/TiO2 as the photocatalyst. The Pd/TiO2 film photocatalyst is prepared by the sol-gel and dip-coating process to prepare TiO2 film and the pulse arc plasma method is used to dope Pd on TiO2 film. The prepared Pd/TiO2 film was characterized by SEM, EPMA, STEM, EDS, and EELS. This study also investigated the performance of CO2 reduction under the illumination condition of Xe lamp with or without ultraviolet (UV) light. As a result, it is revealed that when the molar ratio of CO2/H2/H2O is set at 1:0.5:0.5, the best CO2 reduction performance has been obtained under the illumination condition of Xe lamp with and without UV light. In addition, it is found that the optimum Pd loading weight is 3.90 wt%. The maximum molar quantities of CO and CH4 produced per unit weight of photocatalyst are 30.3 μmol/g and 22.1 μmol/g, respectively, for the molar ratio of CO2/H2/H2O = 1:0.5:0.5 under the condition of Xe lamp illumination with UV light. With UV light, C2H4 and C2H6, as well as CO and CH4 are also produced by the Pd/TiO2 film photocatalyst prepared in this study.