Strain Effect in PdCu Alloy Metallene for Enhanced Formic Acid Electrooxidation Reaction

Abstract

Developing high-activity and high-durability Pd-based electrocatalysts is an important strategy to promote their commercial application. Herein, a smaller particle size and ultrathin sheet-like PdCu alloy metallene (PdCuene) were successfully prepared by using a one-pot wet chemistry method for FAOR. Experimental measurements indicated that the introduction Cu into Pd lattice induces a significant compressive strain effect through lattice mismatch between Pd and Cu, and the strain effect optimizes the electronic structure of Pd, as well as the high electrochemical surface area, increased exposure of active sites, and appropriate lattice strain have been demonstrated as factors that influence the enhancement of intrinsic activity and the acceleration of kinetics, thereby improving FAOR performance. Moreover, the stronger lattice strain of 0.85% would facilitate surface adsorption and dissociation of formic acid. Specifically, the optimized PdCuene exhibits enhanced mass activity and specific activity with current densities of 2.31 A mgPd−1 and 4.09 mA cm−2, respectively, which transcend the activities of Pd metallene (1.44 A mgPd−1 and 2.73 mA cm−2) and commercial Pd/C (0.6 A mgPd−1 and 1.53 mA cm−2). Meanwhile, PdCuene displayed obvious enhanced durability. The work provides an approach to modulate the lattice strain engineering, which represents a highly promising strategy for designing efficient FAOR electrocatalysts.