부산대학교 도서관

A series of Pd/TiO2photocatalysts were synthesized by a simple glucose reduction method, and their photocatalysis properties were evaluated in an array of CO2hydrogenations. The samples were characterized by XRD, SEM, TEM, EDX, EDX mapping, UV–vis DRS, Raman spectroscopy, PL spectroscopy, XPS, and N2adsorption. In terms of product yields (in micromoles per gram of catalyst), a 1.0 wt % Pd/TiO2catalyst (CH4, 355.62; CO, 46.35; C2H6, 39.69) was found to be superior to pristine TiO2(CH4, 42.65; CO, 4.73; C2H6, 2.7) and other composites under UV irradiation for 3 h, possibly because of a synergistic effect between the palladium nanoparticles and the TiO2support. The palladium nanoparticles on the surface of TiO2substantially accelerated electron transfer and acted as active sites for the adsorption and activation of CO2molecules, to promote CO2hydrogenation. During the photocatalytic CO2hydrogenation, dissociated hydrogen reacts with CO2–activated on the Pd/TiO2photocatalyst to form a new PdC surface species that is stable during the reaction and further transforms to generate methane. A detailed mechanism of photocatalytic CO2hydrogenation is discussed to account for the performance of the Pd/TiO2photocatalyst in the reaction.