Surface reconstruction of AgPdF and AgPd nanoalloys under the formate oxidation reaction

Surface reconstruction of AgPd nanoalloy can improve the catalytic activity, however, the instability of surface oxides formed by reconstruction greatly limits the further application of catalysts. Herein, a density functional theory calculation is first employed to reveal that surface oxidation and fluorination can modify Ag atomic charges and d-band centers on AgPd surface and result in the strengthened OH adsorption and OH-radical desorption on AgPdF(111) surface. The surface reconstruction of AgPdF and AgPd nanoalloys is correlated with catalytic activity and stability through comparing the transformations during formate oxidation reaction (FOR). AgPd pre-catalysts get oxidized into AgPdO true catalysts at the extended upper limit potentials, AgPdF catalysts maintain unreconstructed, exhibit the higher peak current density of 2.3 AmgPd−1 and activity retention of 54% after 600 CV cycles. During the long term potentiostatic polarization tests, AgPdO true catalyst get reconstructed back to AgPd pre-catalyst, unexpectedly, AgPdF catalyst with stable interface maintains FOR activity up to 78 hours and higher current density of 0.19 AmgPd−1. This systematic work, for the first time, not only highlights the dual roles of surface reconstruction in enhancing catalytic property, but also promotes further research on the correlation of surface reconstruction with FOR properties.