Perovskite oxides offer efficient photocatalytic properties for CO2 reduction to methanol. In this study, LaMnO3+δ nanocrystals were fabricated by the solgel combustion method. The structural properties including lattice constants, occupancies, Mn–O lengths, and Mn–O–Mn angle were studied by Rietveld refinement. Jahn–Teller distortion and O-2p and Mn-3d hybridization have been investigated using the structural parameters and lattice dynamics characterized by Fourier-transform far-infrared spectroscopy. The electron transitions near the lower edge of conduction band were studied by diffuse reflectance spectroscopy. LaMnO3+δ exhibited laser-induced photocatalytic activity for reductive conversion of CO2 to methanol under both visible (532 nm) and infrared (1064 nm) irradiation. The methanol yield as a function of irradiation time was investigated by the gas chromatographic analysis. After 20 min of irradiation at 532 nm, the methanol yield showed the highest value (970 μmol), while the methanol started to degrade with further irradiation time. The recycling stability test from the repeatedly used LaMnO3+δ sample showed the high stability of the catalyst. The authors demonstrated that in addition to the appropriate bandgap energy, the length of eg↑ in the conduction band plays a significant role in the photocatalytic properties of the perovskites with Jahn–Teller distortion under visible and infrared irradiations.

中文翻译：

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钙钛矿LaMnO3上激光诱导CO2光催化还原成甲醇

钙钛矿氧化物为二氧化碳还原为甲醇提供了有效的光催化性能。本研究采用溶胶凝胶燃烧法制备了 LaMnO3+δ 纳米晶。通过 Rietveld 细化研究了结构特性，包括晶格常数、占有率、Mn-O 长度和 Mn-O-Mn 角。使用傅里叶变换远红外光谱表征的结构参数和晶格动力学研究了 Jahn-Teller 畸变和 O-2p 和 Mn-3d 杂化。通过漫反射光谱研究了导带下边缘附近的电子跃迁。在可见光 (532 nm) 和红外 (1064 nm) 照射下，LaMnO3+δ 表现出激光诱导的光催化活性，可将 CO2 还原转化为甲醇。通过气相色谱分析研究作为照射时间的函数的甲醇产率。在 532 nm 照射 20 分钟后，甲醇产率显示出最高值（970 μmol），而随着照射时间的延长，甲醇开始降解。重复使用的 LaMnO3+δ 样品的循环稳定性测试表明催化剂的高稳定性。作者证明，除了合适的带隙能量外，导带中 eg↑ 的长度对可见光和红外辐射下具有 Jahn-Teller 畸变的钙钛矿的光催化性能也起着重要作用。重复使用的 LaMnO3+δ 样品的循环稳定性测试表明催化剂的高稳定性。作者证明，除了合适的带隙能量外，导带中 eg↑ 的长度对可见光和红外辐射下具有 Jahn-Teller 畸变的钙钛矿的光催化性能也起着重要作用。重复使用的 LaMnO3+δ 样品的循环稳定性测试表明催化剂的高稳定性。作者证明，除了合适的带隙能量外，导带中 eg↑ 的长度对可见光和红外辐射下具有 Jahn-Teller 畸变的钙钛矿的光催化性能也起着重要作用。