Photocatalytic reduction of CO2 with H2O is a fascinating approach to convert CO2 into available fuels using solar energy as driven force. However, it still suffers from low efficiency owing to the instinct stability of CO2. In this work, a hybrid photocatalyst of rutile TiO2 nanorods supported on MgAl layered double oxides (TiO2/MgAl-LDO) were designed and facilely fabricated via an in situ growth followed by a high temperature calcination process. The resulted TiO2/MgAl-LDO demonstrated significantly enhanced photocatalytic reduction of CO2 with the optimal CO and CH4 evolution of 0.65 and 1.60 μmol in 8 h reaction under ambient temperature, which is ca. 4.6 and 48 times that of TiO2 respectively. X-ray photoelectron spectroscopy revealed a strong electron interaction between TiO2 and MgAl-LDO, as well as electrochemical characterization showed enhanced photocurrent, suggesting a promoted charge separation in photocatalytic process. CO2-temperature-programmed desorption (CO2-TPD) unveiled the relatively active bicarbonate, bidentate carbonate and monodentate carbonate species were formed on MgAl-LDO, which could boost the CO2 reduction half-reaction. Meanwhile, NH3-TPD revealed acidic sites existed in TiO2/MgAl-LDO, which could act as active sites for H2O adsorption and activation and thus promote the H2O oxidation half-reaction. The strategy of simultaneous promotion on the reduction and the oxidation half-reactions will open a new vane to fabricate highly efficient catalysts toward photocatalytic reduction of CO2 with H2O. A hybrid photocatalyst of MgAl layered double oxides supported rutile TiO2 with abundant acidic and/or basic sites exhibit significant enhancement on the photocatalytic reduction of CO2 with H2O under ambient temperature.

中文翻译：

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常温下用 H2O 增强光催化还原金红石型 TiO2/MgAl 层状双氧化物上的 CO2

用 H2O 光催化还原 CO2 是一种利用太阳能作为驱动力将 CO2 转化为可用燃料的迷人方法。然而，由于二氧化碳的本能稳定性，它仍然存在效率低下的问题。在这项工作中，设计了一种负载在 MgAl 层状双氧化物（TiO2/MgAl-LDO）上的金红石型 TiO2 纳米棒的混合光催化剂，并通过原位生长和高温煅烧工艺轻松制造。所得的 TiO2/MgAl-LDO 显示出显着增强的 CO2 光催化还原，在环境温度下反应 8 小时，最佳 CO 和 CH4 析出量为 0.65 和 1.60 μmol，约为 分别是 TiO2 的 4.6 倍和 48 倍。X 射线光电子能谱揭示了 TiO2 和 MgAl-LDO 之间的强电子相互作用，以及电化学表征显示光电流增强，表明光催化过程中促进了电荷分离。CO2 程序升温脱附（CO2-TPD）揭示了在 MgAl-LDO 上形成了相对活泼的碳酸氢盐、双齿碳酸盐和单齿碳酸盐物种，这可以促进 CO2 还原半反应。同时，NH3-TPD表明TiO2/MgAl-LDO中存在酸性位点，可以作为H2O吸附和活化的活性位点，从而促进H2O氧化半反应。同时促进还原和氧化半反应的策略将为制造高效催化剂以光催化水还原 CO2 开辟新的方向。