Engineering pore-confined ultrafine Pt nanoparticles in hollow mesoporous carbon spheres for synergistically enhanced bifunctional electrocatalysis of sustainable hydrogen evolution and ethylene glycol oxidation

Rational design of Pt-based electrocatalysts necessitates precise control over nanoparticle size and electronic structure to optimize activity and durability. We develop a mesopore confinement strategy to synthesize size-tunable Pt nanoparticles embedded in hollow mesoporous carbon spheres (HMCs) with adjustable pore diameters (5-20 nm). Benefitting from the mesopore confinement, the optimized Pt/HMCs-10 demonstrates exceptional electrocatalytic performance for both the hydrogen evolution reaction (HER) and ethylene glycol oxidation reaction (EGOR), surpassing commercial Pt/C. In-situ FTIR spectroscopy, in-situ electrochemical impedance spectroscopy (EIS) and other techniques elucidate the structure-activity relationship. For HER, Pt/HMCs-10 delivers a mass activity of 5,534 mA mg Pt -1 at -40 mV (vs. RHE), 15.7 times higher than Pt/C, owing to optimized work function modulation and accelerated charge transfer. In EGOR, it achieves a record mass activity of 10,696 mA mg Pt -1 , 3.8 times higher than Pt/C. which is attributed to stabilized *OC-CH 2 OH intermediates (ΔG = 7.54 kJ mol⁻¹) and efficient C-C cleavage. The mesoporous architecture ensures exceptional Pt nanoparticle dispersion and long-term stability. This work establishes a general strategy for designing confined-metal electrocatalysts while uncovering how pore confinement simultaneously tunes electronic properties and reaction pathways.