Stable Strain State of Single-Twinned AgPdF Nanoalloys under Formate Oxidation Reaction

Surface reconstruction as common phenomenon during catalysis complicates the prediction and modeling on catalytic activity of the nanoalloy, hence developing a stable structure to be resistant to surface restructuring would provide an ideal prototype for substantial and reliable mechanism analysis. Herein, the single-twinned structure in inverse AgPdF catalyst is constructed to enhance the catalytic activity and stability for the formate oxidation reaction (FOR). The single-twinned AgPdF nanoalloy (t-AgPdF) catalyst exhibits an enhanced peak current density of 4.6 A mg_Pd⁻¹, a reduced onset potential of 0.44 V, a higher activity retention of 55.7% after 600 cycles, and a longer activity retention time of 55.9 h. Additionally, the t-AgPdF catalyst presents a higher hydrogen generation rate of 1.11 mL mg_Pd⁻¹ than that of single-crystalline AgPd nanoalloy (AgPd) catalyst, and density functional theory calculations reveal that t-AgPdF(111) surface exhibits a reduced activation energy of 0.59 eV for formate decomposition reaction. Impressively, the t-AgPdF maintains compressive and tensile strain state along the Σ3 twin boundaries before and after the FOR, in contrast to AgPd. This is the first time to reveal that the nanotwinned structures contribute inverse t-AgPdF catalysts the catalytic active sites with stable strain state since starting reaction for the FOR.