A General Strategy for the In Situ Polymer Carbonization Synthesis of Rare-Earth Ion-Doped Pt Catalysts with Enhanced Hydrogen Evolution Performance

In response to the urgent demand for highly efficient and stable electrocatalysts for the hydrogen evolution reaction (HER) in sustainable energy applications, this study developed a class of high-performance RE–Pt@CN catalysts based on the synergistic effect of rare-earth doping and nitrogen-doped carbon supports. Using 2,2′-bipyridine-5,5′-dicarboxylic acid (DPDC) as a bifunctional ligand, a series of binary catalysts, including Sm–Pt@CN and various RE–Pt systems (RE = Sm, Ce, Gd, Pr, Er, Eu, and Yb), were successfully constructed on nitrogen-doped carbon nanotubes via a hydrothermal-carbonization reduction method. These catalysts exhibit a uniform structure and excellent stability. The Sm–Pt@CN catalyst prepared under optimal conditions (heat treatment at 800 °C, n (Pt):n (Sm):n (DPDC) = 1:1:3) shows uniformly dispersed nanoparticles (approximately 3.7 nm) and outstanding HER activity and stability in 0.5 M H2SO4 electrolyte: it requires an overpotential of only 88 mV to achieve a current density of 100 mA·cm–2, exhibits a Tafel slope of 22.96 mV·dec–1, and delivers a mass activity of 2.30 A·mg–1 at an overpotential of 100 mV, significantly outperforming commercial Pt/C (η100 = 99.8 mV, 26.68 mV·dec–1). The doping of Sm effectively enhances the metal–support interaction between platinum and the carbon carrier, inhibiting nanoparticle growth and aggregation, thereby endowing the catalyst with superior electrochemical stability. The synthesis strategy demonstrates good universality, as other rare-earth-doped platinum-based catalysts (e.g., Ce, Gd, Pr, Er, Eu, and Yb) also exhibit excellent HER performance. This work provides a new material platform and synthetic pathway for the development of highly efficient, stable, and low-platinum-loading electrocatalysts for water electrolysis.