Solvent Free Synthesis of PdZn/TiO Catalysts for the Hydrogenation of CO to Methanol.

Catalytic upgrading of CO to value-added chemicals is an important challenge within the chemical sciences. Of particular interest are catalysts which are both active and selective for the hydrogenation of CO to methanol. PdZn alloy nanoparticles supported on TiO via a solvent-free chemical vapour impregnation method are shown to be effective for this reaction. This synthesis technique is shown to minimise surface contaminants, which are detrimental to catalyst activity. The effect of reductive heat treatments on both structural properties of PdZn/TiO catalysts and rates of catalytic CO hydrogenation are investigated. PdZn nanoparticles formed upon reduction showed high stability towards particle sintering at high reduction temperature with average diameter of 3-6 nm to give 1710 mmol kg h of methanol. Reductive treatment at high temperature results in the formation of ZnTiO as well as PdZn, and gives the highest methanol yield.