Theory Study The CO Removal Reaction On Alag_n, Cu_nNi Clusters

The CO removal reactions have attracted great interest in recent years because the reactions have many human life and industrial applications, such as vehicle exhaust cleaning, eliminating of CO in spacecraft and submarine, CO sensors, gas purification of closed CO2laser, mine rescue devices and purification of the feed stream of fuel cells. There are three categories catalysts used in the CO removal reactions:precious metal catalysts, non-precious metal catalysts, and mixing precious and non-precious metal catalysts. Although Precious metal catalysts have the high catalytic performance, the price spent expensive. Non-noble metal catalysts are cheap, but catalytic properties are not as precious metal catalysts. In recent years, scientists have focused on precious metals and non-noble metal doping, which greatly reduce the cost of the catalyst and enhance catalyst activity. However, Al and Cu are widely distributed in nature and cheap metal. Clusters have the great table body ratio and good catalytic activity in the surface adsorption, which have very important application, etc. The structure and electrical characteristics of aluminum alloy and copper alloy clusters have also been attracted the attention of people. Based on the above reasons, in this paper, the main purpose studies the CO removal reaction mechanism of AIAgn and CunNi clusters, expecting to provide a theoretical basis and guidance for the development of the new catalyst materials. All calculations are under the GaussianO3packages. Full optimized structures and normal-mode frequencies are found using the DFT/PBE method. An all-electron basis set6-31G*is used for Al, H, C and O atoms. The LANL2DZ pseudopotential is adopted for the valence electrons of Cu and Ni atoms. The main contents are listed as follows:1. We have made an exhaustive study of the mechanism of CO oxidation catalyzed by AIAgn (n=1-3) alloy clusters through the Langmuir-Hinshelwood path. The structures of the AIAgn (n=1-3) clusters, CO and O2adsorption on AIAgn (n=1-3) clusters and CO oxidation catalyzed by AIAgn (n=1-3) clusters were investigated. It is shown that CO adsorption behavior on CunNi (n=3-12) are more stronger than O2; mixing two different metals (Al and Ag) can have beneficial effects on the catalytic activity and the alloyed AIAg3cluster is proposed as the best effective Nanocatalysts.2. We have made an exhaustive study of the mechanism of CO-PROX reaction catalyzed by CunNi (n=3-12) clusters on gas phase.The structures of the CunNi (n=3-12) clusters, H2adsorption and dissociation and the detailed reaction mechanisms, O2adsorption on CunNiH-H (n=3-12) and CO-PROX catalyzed by CunNi (n=3-12) clusters were investigated. Our results indicated that the Cu12Ni is the most efficient catalyst for the H2dissociation and the Cu6Ni cluster is proposed as the best effective nanocatalysts for CO-PROX in excess hydrogen among CunNi (n=3-12) clusters. To gain insight into the adsorption and dissociation of H2molecule effect in the catalytic activity over the Cu12Ni cluster and the potential energy surfaces about PROX of CO oxidation on Cu6Ni, the nature of the interaction between the adsorbate and substrate was analyzed by detailed electronic local densities of states (LDOS) as well as molecular structures.3. We have made an exhaustive study of the mechanism of Water-Gas Shift (WGS) Reaction catalyzed by CunNi (n01-12) clusters. The structures of the CunNi (n=1-12) clusters, CO and H2O adsorption on CunNi (n=1-12) and WGS reaction catalyzed by CunNi (n=1-12) clusters were investigated. Our results indicated that CO adsorption behavior on CunNi (n=1-12) are much stronger than H2O. Cu6Ni cluster is proposed as the best effective nanocatalysts for WGS reaction among CunNi (n=1-12) clusters. The potential energy surfaces about WGS reaction on Cu6Ni, the nature of the interaction between the adsorbate and substrate was analyzed by detailed electronic local densities of states (LDOS) as well as molecular structures. We believe that the present analysis offers interesting perspectives in the understanding and exploitation of heterogeNeous subannocatalysts.