Superhydrophilic electrodes 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 H₂SO₄ and the highest mass activity of 40.2 A mg⁻¹_Pt at 100 mV. Moreover, the Pt-1000@d-CF electrode exhibits superior stability, with only a 35.9% current density decay at 100 mV after an accelerated degradation test of 20 000 cycles, substantially outperforming 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.