Utilizing new metal phase nanocomposites deep photocatalytic conversion of CO2 to C2H4

Abstract

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.