Model Cu/ZnO Catalysts for Methanol Synthesis: The Role of Surface Structure: Progress Report.

摘要

Catalysts based on CuO/ZnO mixtures are well known for their activity and selectivity in the methanol synthesis reaction (CO + 2H2 implies CH3OH). These catalysts are also widely used for water-gas shift (CO + H2O /Yields and reversible/ CO2 + H2 ), which occurs together with methanol synthesis under most conditions. We are attempting to correlate reaction kinetics made at medium-pressure conditions (<10 atm.) on well-defined single-crystal surfaces with: (1) kinetics at similar conditions on high surface area Cu/ZnO catalysts, (2) details of the atomic-level surface structure, and (3) information on adsorption/desorption phenomena available from UHV surface science studies. Model catalysts were constructed based on single crystals where the surface structure is very homogeneous and well characterized using UHV surface analysis. Catalysts include ZnO(0001), Cu(111) and (110), sub-monolayer Cu overlayers on ZnO(0001), ZnO(sub x) overlayers on Cu surfaces, and Cs overlayers on Cu surfaces. To better understand the mechanism of promotion, we have experimentally studied the interactions of CO, CO2 , H2O and formic acid with the clean and cesium-doped Cu(110) surface, and the coadsorption of H2O and oxygen on that surface. (ERA citation 14:004250)