Surface-Engineered Ultrathin PtPd Nanowires: Some Insights into Structure and Electrocatalytic Activity

Engineering the electronic structure of heterogeneous catalysts represents a fundamental strategy to improve their electrocatalytic performance, particularly by optimizing their activity, selectivity, and resistance to deactivation. Among these approaches, the design of multimetallic catalysts has proven to be especially effective in modulating the d-band center and tuning adsorption energies of the reaction intermediates, thereby enhancing the catalytic efficiency and reducing susceptibility to poisoning. Anisotropic nanostructures, such as nanowires, often outperform their isotropic counterparts due to their high surface-area-to-volume ratio, preferential exposure of specific crystal facets, and enhanced charge transport properties. Despite these advantages, the synthesis of bimetallic single-crystalline nanowires via coreduction methods remains a significant challenge due to the complexities associated with controlled nucleation and alloying at the nanoscale. In this study, we present a generalized and robust synthesis strategy for the fabrication of ultrathin, single-crystalline Pt–Pd alloy nanowires using Pt nanowires as templates. This templated approach enables precise control over the composition and crystallinity, facilitating the formation of homogeneous bimetallic structures with tailored surface properties. The electrocatalytic activities of these Pt–Pd nanowires were systematically investigated for the ethanol oxidation reaction (EOR), methanol oxidation reaction (MOR), and oxygen reduction reaction (ORR). Furthermore, density functional theory (DFT) calculations are employed to elucidate the relationship between the modified surface electronic structure of the alloyed nanowires and their catalytic performance. These results provide mechanistic insights into the role of surface alloying and anisotropic morphology in governing the electrocatalytic behavior, offering a rational framework for the design of Pt-based one-dimensional (1D) nanostructured catalysts.