CO₂ conversion is of great industrial importance in reducing green-house effect and reusing carbon-resource. Most studies are focused on the thermocataltic CO₂ conversion, which usually performs over noble metal catalysts at high temperature and pressure. Recently, photocatalytic CO₂ conversion has caused increasing attention owing to the energy save, low-cost and clean reaction route. The key problem is to design photocatalysts high activity and strong durability. Here, we choose to prepare a novel C@Fe₂C/TiO ternary composite catalyst by reducing organic compounds under an ammonia atmosphere. During CO₂ reduction reaction in aqueous solution, the catalyst exhibits high activity under simulated sunlight with main-product of C₂H₄ (35.483 μmol g^-1h⁻¹). Even irradiating with near-infrared lights, the catalytic conversion still proceeds successfully, but the main-product turns to be CH₄ (18.315 μmol g^-1h⁻¹). Based on the chanracterizations and DFT calculation, the high activity could be attributed to the cooperation between the Fe₂C catalyst toward C₂H₄ and the TiO₂ photocatalyst. Specially, C@Fe₂C/TiO could be excited by NIR lights owing to the narrow-energy band gap. More importantly, the photoelectrons could be easily separated from holes owing to the presence of the Z-scheme heterojunctions, leading to the enhanced photocatalytic activity. This work provides new insights to understand the CO₂ reduction reaction mechanism to develop photocatalysts.

在减少温室效应和再利用碳资源方面，CO ₂转化具有重要的工业意义。大多数研究集中在热催化的CO ₂转化上，该转化通常在高温和高压下在贵金属催化剂上进行。近来，由于节能，低成本和清洁的反应路线，光催化CO ₂转化引起了越来越多的关注。关键问题是设计光催化剂的高活性和强耐久性。在这里，我们选择通过在氨气氛下还原有机化合物来制备新型的C @ Fe ₂ C / TiO三元复合催化剂。在CO ₂期间在水溶液中进行还原反应时，该催化剂在模拟阳光下显示出高活性，其主要产物为C ₂ H ₄（35.483μmolg ^-1 h ^-1）。即使用近红外光照射，催化转化仍然成功进行，但是主要产物变为CH ₄（18.315μmolg ^-1 h ^-1）。基于化学特性和DFT计算，高活性归因于Fe ₂ C催化剂对C ₂ H ₄和TiO ₂光催化剂之间的协同作用。特别是C @ Fe ₂由于窄的能带隙，C / TiO可被近红外光激发。更重要的是，由于存在Z-方案异质结，光电子很容易与空穴分离，从而提高了光催化活性。这项工作为了解CO ₂还原反应机理以开发光催化剂提供了新的见识。