H2O adsorption on the Au and Pd single atom catalysts supported on ceria: A first-principles study

Abstract The interaction of H 2 O molecules with the CeO 2 (1 1 1) and (1 1 0) surfaces with the supported Au and Pd single atom catalysts (Au/CeO 2 and Pd/CeO 2 ) has been studied based on the first-principles calculation. It is found that H 2 O energetically prefers to be dissociative adsorption on the Pd/CeO 2 (1 1 0), Au/CeO 2 (1 1 1) and Au/CeO 2 (1 1 0) surfaces with the adsorption energies of 1.71, 1.91 and 1.40 eV, respectively, while both molecular (1.06 eV) and dissociative adsorption (1.15 eV) may coexist for H 2 O on the Pd/CeO 2 (1 1 1) surface. H 2 O dissociative adsorption is much more exothermic on the Pd/CeO 2 (1 1 0) surface than on the Pd/CeO 2 (1 1 1) surface, while the opposite behavior has been observed for H 2 O adsorption on the Au/CeO 2 surface. The relevant mechanism has been discussed based on the electronic structure analysis. In addition, we have made a comparison between the Pd(Au)/CeO 2 surfaces and the pristine CeO 2 surfaces in terms of the H 2 O adsorption exothermicity and the kinetic barrier of H 2 O dissociation, which indicate that the supported metal single atoms can greatly enhance the chemical activity of CeO 2 toward H 2 O. Our study would give useful insights into the reactions involving H 2 O catalyzed by the CeO 2 -supported Pd and Au nanocatalysts, when the Pd and Au are existing in the form of single atoms.