Abstract
Water is considered as a promoter for the CO oxidation over Au catalysts but experimental evidence of how adsorbed H2O may influence the CO oxidation is scarce.In this study,Au/BN catalysts prepared by deposition method are subjected to calcination at different temperature.Increasing calcination temperature results in more Au particles distributed on BN basal plane,increased water affinity,increased defects on BN,and altered CO oxidation activity.All catalysts exhibit two CO adsorption bands at high relative humidity which are attributable to CO_(ad)on Au~0 and CO(H2O)n species,although only a blue-shifted CO_(ad)is found at nominal dry condition.The turnover frequency is found to correlate with H2O physisorption,with a volcano-shape dependency on surface density and first-layer physisorption enthalpy of H2O_(ad).How the physisorbed H2O may influence CO oxidation over Au/BN is discussed and it implies that(H2O)_(n,ad)cluster is involved in CO activation.
NSTL