The photocatalytic activity of P25 TiO₂ with 0.36 % (w/w) Pt co‐catalyst towards the formation of methane, in the presence of CO₂ and H₂O vapor, is investigated in a flow photoreactor under varying reaction conditions of temperature, water molar fraction in the dosed gas and residence time. Within the range of parameters studied, H₂O molar fraction is found to be the most sensitive parameter, and its increase leads to larger production rates as well as to a significant slow down of photocatalytic activity loss. This observed activation with water content is in contrast to the effect known in neat P25 and it occurs in a regime of very large adsorbed H₂O to CO₂ excess, and can be understood in the context of hole extraction being much slower than electron extraction. These results also constrain the possible interpretation of the nature of the photocatalyst deactivation processes.

中文翻译：

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研究反应条件对CO2和H2O气体在P25-TiO2 / Pt上光催化甲烷生产的影响。应用和机械含义

在流动的光反应器中，在温度变化的条件下，研究了具有0.36％（w / w）Pt助催化剂的P25 TiO ₂在CO ₂和H ₂ O蒸气存在下对甲烷形成的光催化活性，气体中的水摩尔分数和停留时间。在所研究的参数范围内，发现H ₂ O摩尔分数是最敏感的参数，并且其增加导致生产率提高以及光催化活性损失的显着减慢。观察到的与水的活化作用与纯净P25中已知的作用相反，并且发生在非常大的H ₂ O吸附到CO _{2的状态下}空穴提取比电子提取要慢得多。这些结果也限制了对光催化剂失活过程性质的可能解释。