Selective synthesis of carbon monoxide via formates in reverse water-gas shift reaction over alumina-supported gold catalyst

Thermal decomposition of formic acid on SiO2, CeO2 and gamma-Al2O3 was studied as an elementary step of reverse water-gas shit reaction (RWGS) over supported Au catalysts. gamma-Al2O3 showed the highest CO selectivity among the tested oxides in the decomposition of formic acid. Infrared spectroscopy showed the formation of four formate species on gamma-Al2O3: three eta(1)-type and one mu(2)-type species, and these formates decomposed to CO at 473 K or higher. Au-loaded gamma-Al2O3 samples were prepared by a deposition precipitation method and used as catalysts for RWGS. The supported Au catalyst gave CO with high selectivity over 99% from CO2 and H-2, which is attributed to the formation of formates on Au and subsequent decomposition to CO on gamma-Al2O3. (C) 2015 Science Press and Dalian Institute of Chemical Physics. All rights reserved.