In this work, thin layers of MoO₃ were tested as potential photoanodes for water splitting. The influence of photointercalation of alkali metal cation (K⁺) into the MoO₃ structure on the photoelectrochemical properties of the molybdenum trioxide films was investigated for the first time. MoO₃ thin films were synthesized via thermal annealing of thin, metallic Mo films deposited onto the FTO substrate using a magnetron sputtering system. The Tauc and Mott–Schottky plots analysis were performed in order to determine the energy bands position of the investigated material. The photointercalation effect of K⁺ on photoelectrochemical properties of FTO/MoO₃ photoanodes was studied using electrochemical techniques performed under simulated solar light illumination. It was proven that pristine MoO₃ layers cannot act as effective photoanodes for water splitting due to the utilization of the photoexcited electrons in the intercalation process. The photochromic phenomenon related to Mo⁶⁺ centers reduction, and K⁺ intercalation occurs at a potential range in which the photoanode exhibits photoelectrochemical activity towards water photooxidation.

Schematic presentation of the photointercalation phenomenon influence on the photocurrent generation

在这项工作中，测试了MoO _3的薄层作为水分解的潜在光阳极。首次研究了碱金属阳离子（K ⁺）光嵌入MoO ₃结构中对三氧化钼膜的光电化学性能的影响。MoO ₃薄膜是通过使用磁控溅射系统对沉积在FTO基板上的金属Mo薄膜进行热退火而合成的。为了确定所研究材料的能带位置，进行了Tauc和Mott-Schottky曲线分析。K ⁺对FTO / MoO _3的光电化学性质的光嵌入效应使用在模拟太阳光照射下进行的电化学技术研究了光阳极。事实证明，由于在嵌入过程中利用了光激发电子，因此原始的MoO ₃层不能用作有效的水分解阳极。与Mo ⁶⁺中心还原有关的光致变色现象，以及K ⁺嵌入发生在该光电阳极对水的光氧化表现出光电化学活性的电势范围内。

光插层现象对光电流产生的影响的示意图