Density functional study on mechanism of CO oxidation with activated water on O/Au (111) surface

With density functional theory, the mechanism of water-enhanced CO oxidation on oxygen pre-covered Au (111) surface is theoretically studied. First, water is activated by the pre-covered oxygen atom and dissociates to OHads group. Then, OHads reacts with COads to form chemisorbed HOCOads. Finally, with the aid of water, HOCOads dissociates to CO2. The whole process can be described as 1/2H2Oads + H2Oads + 1/2Oads + COads → H3Oads + CO2, gas. One CO2 is formed with only 1/2 pre-covered oxygen atom. That is why more CO2 is observed when water is present on oxygen pre-covered Au (111) surface. Activation energy of each elementary step is low enough to allow the reaction to proceed at low temperature. Supported by the National Natural Science Foundation of China (Grand Nos. 50721091, 20533030, and 50731160010), National Key Basic Research Program (Grant No. 2006CB922004), University of Science and Technology of China (USTC)-Hewlett Packard (HP) High Performancse Computing Center, Supercomputing Center of Chinses Academy of China and Shanghai Supercomputer Center