Photoelectrochemical (PEC) water vapor splitting by using n‐type semiconductor electrodes with a proton exchange membrane (PEM) enabled pure hydrogen production from humidity in ambient air. We proved a design concept that the gas–electrolyte–semiconductor triple‐phase boundary on a nanostructured photoanode is important for the photoinduced gas‐phase reaction. A surface coating of solid‐polymer electrolyte on a macroporous titania‐nanotube array (TNTA) electrode markedly enhanced the incident photon‐to‐current conversion efficiency (IPCE) at the gas–solid interface. This indicates that proton‐coupled electron transfer is the rate‐determining step on the bare TNTA electrode for the gas‐phase PEC reaction. The perfluorosulfonate ionomer‐coated TNTA photoanode exhibited an IPCE of 26 % at an applied voltage of 1.2 V under 365 nm ultraviolet irradiation. The hydrogen production rate in a large PEM‐PEC cell (16 cm²) was 10 μmol min⁻¹.

中文翻译：

---

用于气相水分解的固体聚合物电解质涂层大孔二氧化钛纳米管光电电极

通过使用带有质子交换膜（PEM）的n型半导体电极进行光化学（PEC）水蒸气分解，可以从环境空气中的湿气中产生纯氢气。我们证明了一个设计概念，即纳米结构光阳极上的气体-电解质-半导体三相边界对于光诱导的气相反应很重要。大孔二氧化钛纳米管阵列（TNTA）电极上的固体聚合物电解质表面涂层显着提高了气固界面处的入射光子-电流转换效率（IPCE）。这表明质子耦合电子转移是气相PEC反应在TNTA裸电极上的速率决定步骤。全氟磺酸离聚物涂覆的TNTA光电阳极在施加1的电压时表现出26％的IPCE。在365 nm紫外线照射下为2V。大型PEM‐PEC电池（16厘米）中的氢气产生速率²）为10μmolmin ^-1。