Surface Confinement Etching and Polarization Matter: A New Approach To Prepare Ultrathin PtAgCo Nanosheets for Hydrogen-Evolution Reactions

One of the important objectives in fuel-cell technology is to improve the activity and reduce the loading of Pt for hydrogen-evolution electrocatalysis. Here, an oxidative etching strategy of stacking faults is developed to prepare PtAgCo nanosheets by element-specific anisotropic growth. Sophisticated use of defects in crystal growth allows tailoring the morphology and interfacial polarization to improve catalytic performance of nanosheets for the hydrogen-evolution reaction. Systematic studies reveal that the presence of the stacking faults may be the knob for the formation of nanosheets. In particular, the chemical composition of nanosheets is potentially the key for altering the hydrogen-evolution reaction. As a result, the PtAgCo-II ultrathin nanosheets possess useful HER properties, achieving a current density up to 705 mA cm –2 at a potential of −400 mV.