Investigating the surface chemistry of formaldehyde on the surface of TiO₂ is important in understanding the thermal-catalytic and photocatalytic reactions of formaldehyde on TiO₂-involved catalysts. By combining thermal desorption spectroscopy and X-ray photoelectron spectroscopy, we studied the adsorption, thermo-induced surface reactions, and photo-induced surface reactions of formaldehyde on the rutile TiO₂(011)-(2 × 1) surface. The dominant thermal-catalytic reaction is the formation of ethylene by a reductive carbon–carbon formation reaction of formaldehyde adsorbed at the oxygen vacancy sites, and the dominant photocatalytic reaction is the formation of formate, assisted by the bridge O_2c sites, followed by carbon monoxide formation at elevated temperatures. The surface intermediates of formaldehyde reactions to ethylene and carbon monoxide on the rutile TiO₂(011)-(2 × 1) surface were identified. The effect of the surface structure of the rutile TiO₂(011)-(2 × 1) surface, particularly the oxygen vacancy, on the thermal-catalytic and photocatalytic activity toward formaldehyde was revealed by studying the coadsorption of water and formaldehyde. These results broaden our fundamental comprehension on the reaction mechanism of formaldehyde on the TiO₂ surfaces.

中文翻译：

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金红石型TiO ₂（011）-（2×1）表面上甲醛的表面化学：光催化与热催化

研究甲醛在TiO ₂表面上的表面化学性质对于理解甲醛在TiO ₂参与的催化剂上的热催化和光催化反应非常重要。通过结合热解吸光谱和X射线光电子能谱，我们研究了金红石TiO ₂（011）-（2×1）表面上甲醛的吸附，热诱导的表面反应和光诱导的表面反应。主要的热催化反应是通过氧空位处吸附的甲醛的还原碳-碳形成反应形成乙烯，而主要的光催化反应是在桥O _2c的辅助下形成甲酸盐。位置，然后在高温下形成一氧化碳。确定了金红石型TiO ₂（011）-（2×1）表面上甲醛与乙烯和一氧化碳反应的表面中间体。通过研究水与甲醛的共吸附，揭示了金红石型TiO ₂（011）-（2×1）表面的表面结构，尤其是氧空位对甲醛的热催化和光催化活性的影响。这些结果拓宽了我们对TiO ₂表面上甲醛反应机理的基本理解。