Spontaneous Formate Oxidation on the 2D Surface Metal Fluoride Interface Reconstructed from the AgPdF Surface

Surface reconstruction processes and effects of reconstructed species during the formate oxidation reaction (FOR) remain unclear, limiting the ability to guide the design of efficient stable electrocatalysts through the reconstruction-performance relationship. In this paper, globally stable structures of the adlayer-alloy interface on AgPdF alloy from fluorination-enabled surface reconstruction are predicted via the particle swarm optimization algorithms coupled with density functional theory (DFT) calculations. Various 2D surface metal fluoride (Ag,Pd)Fx adlayers and their FOR catalytic behavior are revealed on the reconstructed AgPdF alloy. Typically, the (Ag3Pd1)F4-AgPd(111) interface is a globally stable structure among all heterointerfaces, and an adlayer of (Ag3Pd1)Fx with x = 1, 2 or x = 3, 4 on the AgPd(111) interface has a fluorine on-surface superstructure or a surface fluoride structure with one surface Pd atom coordinated by four F atoms. Unexpectedly, a metastable (Ag3Pd1)F1-AgPd(111) interface demonstrates all downhill pathways in free energy diagram and an activation energy of 0.04 eV in the rate-determining step from HCOO*bi- to HCOO*mo-, indicating a thermodynamically spontaneous reaction on the heterointerface due to its moderate d-band center and a suitable H, OH, and HCOO- adsorption. This study explores the challenge of designing nanoalloys that undergo reconstruction during catalysis and fill the gap in the reconstruction-performance relationship.