Balanced CO/OH Intermediates for Efficient and CO-Resilient Electrocatalytic Methanol Oxidation via Pt Supported on La-Doped α-MoC

The electrocatalytic methanol oxidation reaction (MOR) over Pt-based catalysts is critical for renewable energy applications. However, its performance is often hampered by CO poisoning and the inefficient utilization of active sites. Regulating the kinetic balance of the CO and OH intermediates through microenvironmental control has emerged as an effective strategy to mitigate these limitations. Here, we present a Pt catalyst supported on lanthanum-doped molybdenum carbide (La-MoC), which leverages the exceptional water-dissociation capability of α-MoC to supply abundant OH species, while precisely controlling the surface coverage through La doping and Pt loading. This dual microenvironmental modulation establishes an optimal ratio between CO on Pt and OH on MoC, thereby accelerating CO oxidation and maximizing reaction kinetics. The resulting Pt/La-MoC catalyst exhibits a remarkable mass activity of 8.58 A mg_Pt^-1 (3.6× higher than commercial Pt/C), excellent stability (92% activity retention after 120 h in 0.1 M KOH and 80% activity retention after 30 h in 1 M KOH), and a low CO oxidation onset potential (∼0.2 V vs RHE). In situ spectroscopic and electrochemical studies confirm that the synchronized cycling of CO and OH intermediates promotes rapid CO removal and active-site regeneration. This work provides a rational design concept centered on intermediate balance, offering new insights into the dynamics of surface reactions in electrocatalysis.