Self-Sustainable Lattice Strains of Morphology-Tuned Nanowires in Electrocatalysis

The lattice structure is known to influence interfacial reactivities of nanoscale alloy catalysts, but little is known about how the lattice strain can be sustainably controlled by the nanoscale morphology under electrocatalytic reaction conditions. Herein, a previously unknown self-regulated stability of lattice strains is demonstrated by engineering highly active platinum-copper alloy nanowires with two distinctive types of morphology. The dendritic alloy nanowires exhibit the best performance for oxygen reduction reaction among the reported platinum-copper alloy catalysts. In comparison with the initial difference of compressive lattice strains between smooth and dendritic nanowires, the strains are shown to be controllable, which coincides with the highly durable electrocatalytic performance throughout the duration of oxygen reduction reaction despite the occurrence of dealloying. By thorough characterizations of the nanowire morphologies, compositions, and lattice strains, the self-regulated stability of lattice strains is revealed to originate from the operation of a combination of morphology-tuned compressive strain and realloying in the dendritic nanowires for the enhanced electrocatalytic activity and durability. These findings have significant implications for the design of high-durability alloy catalysts in heterogeneous catalysis.