3D‐Porous Electrocatalyst with Tip‐Enhanced Electric Field Effect Enables High‐Performance Proton Exchange Membrane Water Electrolyzer

Abstract Hydrogen evolution reaction (HER), as one of the most advanced methods for the green production of hydrogen, is greatly impeded by inefficient mass transfer. Here we present an efficiently reactant enriched and mass traffic system by integrating high‐curvature Pt nanocones with 3D porous TiAl framework to enhance mass transfer rate. Theoretical simulations, in situ Raman spectroscopy and potential‐dependent Fourier transform infrared spectroscopy results disclose that the strong local electric field induced by high‐curvature Pt can greatly promote the H ₃ O ⁺ supply rate during HER, resulting in ∼1.6 times higher H ₃ O ⁺ concentration around the Pt nanocone than that in electrolyte. X‐ray computed tomography and molecular dynamic simulation demonstrate the diffusion coefficient of H ₃ O ⁺ in 3D TiAl framework surpasses that in commercial carbon support by more than 16.7 times. Consequently, Pt/TiAl‐nanocone exhibits a high mass activity of 17.2 mA cm ⁻² _Pt at an overpotential of 100 mV with an ultrahigh TOF value of 42.9 atom ⁻¹ s ⁻¹ . In a proton exchange membrane water electrolyzer, the Pt/TiAl‐nanocone cathode achieves an industrial‐scale current density of 1.0 A cm ⁻² with a cell voltage of 1.88 V at 60 °C and can operate stably for at least 800 h with a sluggish voltage decay rate of 137 µV h ⁻¹ .