Proton-exchange membrane water electrolyzers (PEMWEs) are a promising technology for green hydrogen production; however, interfacial transport behaviors are poorly understood, hindering device performance and longevity. Here, we first utilized finite-gap electrolyzer to demonstrate the possibility of proton transfer through water in PEMWEs. The measured high-frequency resistances (HFRs) exhibit a linear trend with increasing gap distance, where extrapolation shows a lower value compared with HFRs in regular zero-gap electrolyzers, indicating that ohmic resistance could be further reduced. We introduce nanochannels to facilitate mass transport, as evidenced by both liquid-fed and vapor-fed electrolysis. Nanochannel electrodes achieve a voltage reduction of 190 mV at 9 A·cm⁻² compared with the Ir-PTEs without nanochannels. Furthermore, nanochannel electrodes show negligible degradation through 100,000 accelerated-stress tests and over 2,000 h of operation at 1.8 A·cm⁻² with a decay rate of 11.66 μV·h⁻¹. These results provide new insights into localized transport dynamics for PEMWEs and highlight the significance of interfacial engineering for electrochemical devices.

质子交换膜水电解槽（PEMWE）是一种很有前景的绿色制氢技术；然而，人们对界面传输行为知之甚少，这阻碍了器件的性能和寿命。在这里，我们首先利用有限间隙电解槽来证明质子在 PEMWE 中通过水转移的可能性。测量的高频电阻（HFR）随着间隙距离的增加呈现线性趋势，其中外推显示与常规零间隙电解槽中的HFR相比更低的值，表明欧姆电阻可以进一步减小。我们引入纳米通道来促进质量传输，液体馈送和蒸汽馈送电解都证明了这一点。与没有纳米通道的 Ir-PTE 相比，纳米通道电极在 9 A·cm ⁻² 下实现了 190 mV 的电压降低。此外，通过 100,000 次加速应力测试和 1.8 A·cm ⁻² 超过 2,000 小时的运行，纳米通道电极表现出可忽略不计的退化，衰减率为 11.66 μV·h ⁻¹ 。这些结果为 PEMWE 的局部传输动力学提供了新的见解，并强调了界面工程对于电化学器件的重要性。