Superhydrophilic Electrode with Defect-Trapped Pt Nanoparticles Boost the Acidic Hydrogen Evolution Reaction

Abstract

The hydrogen evolution reaction (HER) is a critical electrochemical process in water electrolysis. However, the development of binder-free, self-standing HER electrodes that combine high durability with low cost remains challenging. Herein, we propose a defect-mediated anchoring strategy to construct self-standing Pt electrodes by coupling electrochemical anodization with electrodeposition. Anodization reconstructs carbon fiber paper into a defect-rich, superhydrophilic substrate. During electrodeposition, Pt single atoms immobilized at carbon defect sites serve as nucleation centers and progressively grow into Pt nanoparticles. Benefiting from strong metal-support interactions and improved catalyst utilization, the optimized electrode delivers an ultralow overpotential of 12.7 mV at 10 mA cm⁻ 2 in 0.5 M H 2 SO 4 and a highest mass activity of 1 Pt A 2 mg 40.at 100 mV. Moreover, the Pt-1000@d-CF electrode exhibits superior stability, exhibiting only a 35.9% current density decay at 100 mV after an accelerated degradation test of 20000 cycles, which substantially outperforms commercial Pt/C (47%). This work highlights defect engineering of carbon substrates as an effective strategy to stabilize Pt species while maximizing catalyst utilization in self-standing HER electrodes.