The solar photo-thermochemical cycle (PTC) for the conversion of CO₂ into fuels over metal oxides is a novel and promising method to alleviate the increasing energy crisis and worsening global climate change. Density functional theory (DFT) calculations of the anatase (101) surface of TiO₂ and M-doped TiO₂ (M = Zn, Ni, and Cu) were performed to provide guidance for enhancing the PTC. Additionally, M-doped TiO₂ films were produced using a sol-gel method and applied to the PTC for CO₂ conversion to provide experimental verifications. A maximum, stable production of CO of 10.80 μmol/g was achieved using Cu-doped TiO₂, which was nearly 6.39-fold higher than the amount of CO produced by clean TiO₂. The CO yield was in good agreement with the calculation results. High-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDXS), X-ray diffraction (XRD) and electron spin resonance (ESR) were used to evaluate the crystal structures and morphologies. UV–visible diffuse reflectance spectra (UV–visible DRS), photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) analyses were also conducted to investigate the surface charge-transfer and reaction mechanisms. As a result, a complete cycle reaction mechanism for Cu-doped TiO₂ was proposed. Several key factors of the mechanism were clarified, and an effective guide for nanostructure design was proposed.

用于通过金属氧化物将CO ₂转化为燃料的太阳光热化学循环（PTC）是一种新颖而有前途的方法，可以缓解日益加剧的能源危机和全球气候变化的恶化。进行了TiO ₂和M掺杂的TiO ₂（M = Zn，Ni和Cu）的锐钛矿（101）表面的密度泛函理论（DFT）计算，为增强PTC提供了指导。此外，使用溶胶-凝胶法制备了M掺杂的TiO ₂膜，并将其应用于PTC进行CO ₂转化以提供实验验证。使用铜掺杂的TiO _2可以最大稳定地产生10.80μmol/ g的CO，这比清洁的TiO ₂产生的CO量高出将近6.39倍。一氧化碳收率与计算结果吻合良好。高分辨率透射电子显微镜（HRTEM），能量色散X射线光谱（EDXS），X射线衍射（XRD）和电子自旋共振（ESR）用于评估晶体结构和形态。还进行了紫外可见漫反射光谱（UV-DRS），光致发光（PL）和X射线光电子能谱（XPS）分析，以研究表面电荷转移和反应机理。结果，提出了Cu掺杂的TiO ₂的完整循环反应机理。阐明了机理的几个关键因素，并提出了有效的纳米结构设计指南。