Synergetic catalysis between rare earth-doped g-C₃N₄ and Pt toward enhanced hydrogen oxidation

The tradeoff between hydrogen adsorption binding energy (HBE) and hydroxyl adsorption binding energy (OHBE) critically impacts the sluggish kinetics of hydrogen oxidation reactions (HOR), which significantly impedes the development of anion exchange membrane fuel cells (AEMFCs). Herein, we introduce a novel synergistic catalysis system composed of single rare earth atoms (such as Tb, Ho, Gd, and Er) doped into graphitic carbon nitride (GCN) supported on Pt nanoparticles (GCN-RE-Pt) to balance the tradeoff between HBE and OHBE, thereby enhancing HOR kinetics. In this system, the single rare earth atoms could promote the adsorption of hydroxyl species (OH_ad), facilitating hydrogen oxidation and water generation, and induce a surface charge redistribution in GCN, which modulates the electronic structure of the Pt active centers and optimizes the binding energy of adsorbed hydrogen (H_ad). As a proof of concept, the optimal GCN-Tb-Pt electrocatalyst achieved a kinetic current density of 12.67 mA·cm⁻² at an overpotential of 50 mV, which is markedly higher than that of GCN-Pt (6.49 mA·cm⁻²) and commercial Pt/C (7.28 mA·cm⁻²). This work opens new avenues for the rational design of highly efficient alkaline HOR catalysts through single rare earth atoms modulating synergistic catalysis.