The Facet Dependence of CO Electroreduction Selectivity on a PdAu Bimetallic Catalyst: A DFT Study.

The electrochemical carbon dioxide reduction reaction (CORR) has emerged as a promising approach to addressing global energy and environmental challenges. Alloys are of particular importance in these applications due to their unique chemical and physical properties. In this study, the possible mechanism of the C1 products from the electrochemical reduction of CO on four different surfaces of PdAu alloy bimetallic catalysts is predicted using the density functional theory. The differences in the number of d-band electrons and the charge distribution and morphology of the different surfaces result in differing catalytic activity and selectivity on the same surface. On different surfaces, PdAu alloy bimetallic catalysts have different potential limiting steps in CORR, resulting in differing selectivity. The PdAu (100) surface has a good selectivity for HER, indicating that the increase in the net charge on the surface of the alloy improves the selectivity for HER. The PdAu (211) surface, with a step structure, shows a good selectivity for methanol production from CORR. In addition, an electronic structure analysis shows that the selectivity of the reactions involved in the conversion of adsorbates is determined by the difference between the center of the d-band on the top of the catalyst, where the reactant and the product are located. The results of this study may provide some theoretical basis for designing and developing more efficient and selective CO reduction catalysts.