Increasing the utilization efficiency of platinum is critical for advancing proton exchange-membrane fuel cells (PEMFCs). Despite extensive research on catalysts for the cathodic oxygen reduction reaction (ORR), developing highly active and durable Pt-based catalysts that can suppress surface dealloying in corrosive acid conditions remains challenging. Herein, we report a facile synthesis of bimetallic ultrathin PtM (M = Mo, W, and Cr) nanowires (NWs) composed of group VI B transition metal atomic sites anchored on the surface. These NWs possess uniform sizes and well-controlled atomic arrangements. Compared to PtW and PtCr catalysts, the PtMo_0.05 NWs exhibit the highest half-wave potential of 0.935 V and a mass activity of 1.43 A·mg_Pt⁻¹. Remarkably, they demonstrate a remarkable 23.8-fold enhancement in mass activity compared to commercial Pt/C for ORR, surpassing previously reported Pt-based catalysts. Additionally, the PtMo NWs cathode in membrane electrode assembly tests achieves a remarkable peak power density of 1.443 W·cm⁻² (H₂-O₂ conditions at 80 °C), which is 1.09 times that of commercial Pt/C. The ligand effect in the bimetallic surface not only facilitates strong coupling between Mo (4d) and Pt (5d) atomic orbitals to hinder atom leaching but also modulates the d-states of active site, significantly optimizing the adsorption of key oxygen (*O and *OH) species and accelerating the rate-determining step in ORR pathways.

The ethanol oxidation reaction (EOR) is crucial in direct alcohol fuel cells and chemical production. However, the electro-oxidation of ethanol molecules to produce acetaldehyde and carbon monoxide can poison the active sites of nanocatalysts, resulting in reduced performance and posing challenges in achieving high activity and selectivity for ethanol oxidation. In this study, we employed a dynamic seed-mediated method to precisely modify highly dispersed Ru sites onto well-defined Pd nanocrystals. The oxyphilic Ru sites serve as "OH valves", regulating water dissociation, while the surrounding Pd atomic arrangements control electronic states for the oxidation dehydrogenation of carbonaceous intermediates. Specifically, Ru_0.040@Pd nanocubes (Ru:Pd = 0.04 at.%), featuring (100) facets in Ru-Pd₄ configurations, demonstrate an outstanding mass activity of 6.53 A·mg_Pd⁻¹ in EOR under alkaline conditions, which is 6.05 times higher than that of the commercial Pd/C catalyst (1.08 A·mg_Pd⁻¹). Through in-situ experiments and theoretical investigations, we elucidate that the hydrophilic Ru atoms significantly promote the dynamic evolution of H₂O dissociation into OH_ads species, while the electron redistribution from Ru to adjacent Pd concurrently adjusts the selective oxidation of C₂ intermediates. This host–guest interaction accelerates the subsequent oxidation of carbonaceous intermediates (CH₃CO_ads) to acetate, while preventing the formation of toxic *CH_x and *CO species, which constitutes the rate-determining step.

Fine regulation of geometric structures has great promise to acquire specific electronic structures and improve the catalytic performance of single-atom catalysts, yet it remains a challenge. Herein, a novel seed encapsulation–decomposition strategy is proposed for the geometric distortion engineering and thermal atomization of a series of Cu-N_x/S moieties anchored on carbon supports. During pyrolysis, seeds (Cu²⁺, CuO, or Cu₇S₄ nanoparticles) confined in metal organic framework can accommodate single Cu atoms with Cu–N or Cu–S coordination bonds and simultaneously induce C–S or C–N bond cleavage in the second coordination shell of Cu centers, which are identified to manipulate the distortion degree of Cu-N_x/S moieties. The severely distorted Cu-N₃S molecular structure endows the resultant catalyst with excellent oxygen reduction reaction activity (E_1/2 = 0.885 V) and zinc-air battery performance (peak power density of 210 mW·cm⁻²), outperforming the asymmetrical and symmetrical Cu-N₄ structures. A combined experimental and theoretical study reveals that the geometric distortion of Cu-N_x/S moieties creates uneven charge distribution by a unique topological correlation effect, which increases the metal charge and shifts the d-band center toward the Fermi level, thereby optimizing the inter-mediate adsorption energy.