Zn Loading Effects on the Selectivity of PdZn Catalysts for CO2 Hydrogenation to Methanol

Abstract

Abstract PdZn/TiO 2 catalysts have been investigated for the hydrogenation of CO 2 to methanol. Varying the ratio of Pd and Zn using TiO 2 as a support has a dramatic effect on catalytic performance. Chemical vapour impregnation was used to produce PdZn alloys on TiO 2 and X-ray diffraction, X-ray photoelectron spectroscopy, and scanning transmission electron microscopy revealed changes in the structure at varying total PdZn molar ratios. Compared to monometallic Pd/TiO 2 , introducing a low loading of Zn drastically changes product selectivity. When Pd is alloyed with Zn above a total Zn/Pd = 1 molar ratio, methanol selectivity is improved. Therefore, for enhanced methanol productivity, it is crucial for the Zn loading to be higher than that required for the stoichiometric formation of the 1:1 β-PdZn alloy. Graphical Abstract