MgFe₂O₄ spinel with abundant oxygen vacancy was synthesized by a simple precipitation method, and tested in photocatalytic reduction of CO₂ with water vapor as reductant. A series of characterization including XRD, XPS, EPR, PL spectrum, UV–vis DRS and TPD-CO₂ were performed to investigate the influence of calcination temperature on morphology, optical and electronic properties of MgFe₂O₄ spinel. The results demonstrated that the oxygen vacancy concentration increases first and then decreases with the increase of calcination temperature. By introducing oxygen vacancies, the recombination of photogenerated electron-hole pairs was significantly suppressed, visible light absorption and chemisorption capacity of CO₂ were dramatically boosted. Mg-Fe-750 with the richest oxygen vacancies exhibits the highest photocatalytic activity, for which the production rate of CO and H₂ was 24.4 and 34.3 μmol/gcat/h, respectively.

采用简单的沉淀法合成了具有丰富氧空位的MgFe ₂ O ₄尖晶石，并以水蒸气为还原剂进行CO ₂光催化还原试验。进行了一系列表征，包括 XRD、XPS、EPR、PL 光谱、UV-vis DRS 和 TPD-CO ₂以研究煅烧温度对 MgFe ₂ O ₄形貌、光学和电子性质的影响尖晶石。结果表明，随着煅烧温度的升高，氧空位浓度先增大后减小。通过引入氧空位，显着抑制了光生电子-空穴对的复合，显着提高了CO _{2 的}可见光吸收和化学吸附能力。具有最丰富氧空位的Mg-Fe-750表现出最高的光催化活性，其CO和H ₂的产率_分别为24.4和34.3 μmol/gcat/h。