Photo-catalytic performance for oxide films, here for inkjet-printed TiO₂ (ca. 1 μm thickness on FTO) and for spray-pyrolysis-coated Nb₂O₅ (ca. 1 μm thickness on FTO), is affected by oxygen vacancies that form during vacuum-heat treatment at 550 °C. The effects of the oxygen vacancies are associated with formation of Ti(III) and Nb(IV) sites, respectively, and therefore optically visible as “grey” coloration. Photo-electrochemical light-on-off transient experiments are performed in the limit of thin film photoanodes, where front and back illumination result in the same photo-current responses (i.e. with negligible effects from internal light absorption gradients). It is shown that generally the magnitude of photo-currents correlates linearly with light intensity, which is indicative of dominant “photo-capacitive” behaviour. At an applied voltage of 0.4 V vs. SCE (in the plateau region of the photo-current responses) the potential and also the pH (going from 1.0 M KOH to 0.1 M HClO₄ in the presence of methanol quencher) have no significant effect on photo-currents; that is, surface chemical/kinetic effects appear to be unimportant and interfacial hole transfer may be rate limiting. Under these conditions (and based on a simplistic mechanistic model) changes in photo-currents introduced by oxygen vacancy doping (detrimental for TiO₂ and beneficial for Nb₂O₅) are assigned primarily to changes in electron mobility.

氧空位会影响氧化膜的光催化性能，此处的氧化膜对喷墨打印的TiO ₂（FTO上的厚度约为1μm）和喷涂热解涂层的Nb ₂ O ₅（FTO上的厚度约为1μm）具有影响。在550°C的真空热处理过程中形成的。氧空位的影响分别与形成Ti（III）和Nb（IV）的位点有关，因此在光学上可见为“灰色”色。在薄膜光阳极的极限范围内进行光电化学开-关瞬态实验，其中正面和背面照明会产生相同的光电流响应（即。内部光吸收梯度的影响可忽略不计）。结果表明，通常光电流的大小与光强度线性相关，这表明主要的“光电容”行为。在0.4伏的施加电压VS。SCE（在光电流响应的平稳区域）的电势以及pH值（在存在甲醇猝灭剂的情况下，从1.0 M KOH到0.1 M HClO _4）对光电流没有显着影响；也就是说，表面化学/动力学效应似乎并不重要，而界面空穴转移可能是速率限制。在这些条件下（基于简单的机理模型），氧空位掺杂（对TiO ₂不利）引入的光电流变化且对Nb ₂ O ₅有益）主要是指电子迁移率的变化。