Abstract: Aiming at the core challenges of sluggish oxygen evolution reaction (OER) kinetics and high reaction energy barrier at the anode of proton exchange membrane (PEM) water electrolysis, as well as the industrial bottlenecks of high iridium consumption and prohibitive cost for iridium-based catalysts, a trace Mn-doped Ir-Mn_TD/C catalyst was prepared via a solvothermal method. Systematic characterization results reveal that trace Mn is uniformly doped into the Ir lattice without forming an independent phase. This doping effectively modulates the electronic structure of Ir, accelerates electron transfer at the electrode interface and the multi-step oxidation process, optimizes the adsorption behavior of oxygen-containing intermediates. Meanwhile, it significantly improves the dispersion of nanoparticles on the carbon support as well as the electrochemical active area which broadens the active interface and enriches active sites, laying a solid structural foundation for outstanding electrocatalytic performance. Electrochemical tests show that the catalyst achieves an overpotential of only 283 mV to reach a current density of 10 mA·cm^-2, with a Tafel slope of 67.87 mV·dec^-1 and a high mass activity of 1400 mA·mg^-1 in 0.1 mol·L^-1 HClO₄. At the same time, only negligible performance degradation occurs upon 10000 accelerated durability cycles, and the catalyst still maintains excellent catalytic activity. This study confirms that the trace heteroatom doping strategy can simultaneously enhance both the OER activity and stability of iridium-based catalysts without significantly increasing the cost. It provides reliable technical routes and theoretical references for the design and development of high-performance, low-cost catalysts for acidic water electrolysis.

Key words: Proton exchange membrane, oxygen evolution reaction, Ir-based catalyst, trace Mn doping