Interfacial Effects in PdAg Bimetallic Nanosheets for Selective Dehydrogenation of Formic Acid

Two-dimensional ultrathin PdAg bimetallic nanosheets are fabricated and used as model catalysts for understanding the synergetic effects in bimetallic nanocatalysts. The ultrathin nature of the nanosheets allows us to probe the electronic and geometric structures using XPS and X-ray absorption spectroscopy. The as-prepared bimetallic nanosheets show high catalytic activity for selective dehydrogenation of formic acid, especially when the Ag/Pd ratio reaches 1. The superior activity is attributed to the electronic and geometric effect generated from the Pd-Ag interfaces in the catalysts. Our studies reveal increased bond distances of Pd-Pd and decreased Ag-Ag bond lengths in the PdAg bimetallic nanosheets. Pd is electronically promoted by Ag to give enhanced catalysis. Moreover, the geometric effect generated from the PdAg alloyed surface enhances the catalysis by suppressing CO poisoning on the catalysts, which is confirmed by electrochemical FTIR measurements.