Quasi‐Chimney Electrode Boosts Hydrogen Evolution Reaction via Polarized Laplace Pressure

ABSTRACT The effect of mass transfer on hydrogen evolution reaction (HER) is significantly underestimated under high‐current‐density conditions. Here, we designed a quasi‐chimney electrode by integrating 3D superaerophilic microchannels with superaerophobic Pt catalysts to elucidate the influence of mass transfer on HER. Upon encountering superaerophilic channels, hydrogen (H 2 ) bubbles generated on Pt catalysts experience Laplace pressure polarization at the bubble/channel interface, which drives both surface and internal bubbles from the superaerophobic catalytic sites into the superaerophilic network, functioning as a micro‐chimney for efficient bubble transport. In addition, the superaerophilic channels shorten the diffusion path of dissolved H 2 to the air/water interface, thereby reducing the dissolved H 2 concentration. This mass‐transfer enhancement yields an exceptional HER performance (a record‐low overpotential of about −30 mV at −100 mA cm −2 , and a high current density of −2.93 A cm −2 at −0.3 V vs RHE in H 2 SO 4 (0.5 M) along with remarkable durability, confirmed by