The catalytic performance of Cu n Au (n = 3–12) clusters for preferential oxidation of CO in hydrogen-rich stream

Abstract

The CO preferential oxidation (CO-PROX) reaction is the simplest and most cost-effective method to purify reformed H2. We investigated the catalytic performance of Cu n Au (n = 3–12) clusters for CO-PROX in excess hydrogen using density functional theory calculations. The exploration on catalytic mechanism of CO-PROX reaction showed the formation of hydroxyl and atomic oxygen synchronously was the element step we found for the first time, and the mechanism also via the main intermediates of carboxylic. Our results showed that Cu n Au clusters reveal extremely activity for the CO-PROX reaction. In particular, Cu8Au regards as the best surface for CO-PROX reaction because of the lower activation barrier compared with other Cu n Au clusters. To explain the high catalytic activity of Cu n Au clusters, the nature of the interaction between adsorbate and substrate was also analyzed by detailed electronic projected density of states. Our studies provide insight into the Cu–Au catalysts, which may be helpful in developing efficient catalysts for important industrial reaction of CO-PROX.