Effects of indium doping on methanol deep oxidation over Ag/CeO2 catalysts

Abstract

Ce_1−xIn_xO_δ composite oxides (x = 0–0.20) doped with an increasing amount of indium ions were synthesized using a hydrothermal method and the supported Ag/Ce_1−xIn_xO_δ catalysts were used in the catalytic deep oxidation of methanol. All the catalysts were characterized using XRD, N₂ adsorption–desorption, Raman, H₂-TPR, XPS, etc. The results show that appropriate doping of indium (x = 0.10) leads to the formation of Ce_1−xIn_xO_δ single-phase solid solution, while the crystal structure and microstructure change with the increase of indium content. In addition, due to the appropriate amount of indium doping, the surface oxygen vacancy content of the carrier increases and the interaction between Ag and the carrier is enhanced, thus providing more active interfaces and increasing the reduction capacity of the catalyst. With increasing indium doping, the catalytic activity shows a trend of first increasing and then decreasing, and Ag/Ce_0.90In_0.10O_δ shows the best catalytic activity, with light-off temperature (T₅₀) and full conversion (T₉₀) of 130 and 160 °C, respectively. And Ag/Ce_0.90In_0.10O_δ also has a good durability.