Doping hetero-metal ions in semiconductors, especially metal oxides, is a common practice to elevate their photocatalytic reduction activity. However, the underlying enhancement mechanism of doping different metal ions into the host lattice on photocatalytic CO₂ reduction has been rarely explored and thus remains unclear. In this work, CeO₂ nanoparticles doped with three different metal ions (CeM, M = Y, La, Mo) have been synthesized, which exhibited significantly improved photo-reduction CO₂ activity. According to the analysis of Electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS), Y and Mo doping results in increased oxygen vacancy concentration in CeO₂, which promotes the absorption of UV–visible light and the separation/transfer of electrons and holes, consequently elevating the catalytic activity. More importantly, through in-situ FT-IR, CO₂ adsorption/activation and the intermediates generated on catalyst surface during CO₂ photoreduction reaction were investigated and discussed in-depth. Similar carbonates and hydrocarbonates, such as HCO₃⁻, b-CO₃²⁻ and m-CO₃²⁻, have been found to be produced on CeO₂ and CeM, while these intermediates accumulated and strongly covered on the catalyst surface have been revealed to be responsible for the gradually declined CO₂ reduction activity and stability.

在半导体中掺杂异质金属离子，尤其是金属氧化物，是提高其光催化还原活性的常见做法。然而，在光催化CO ₂还原中将不同金属离子掺杂到主晶格中的潜在增强机制很少被探索，因此仍不清楚。在这项工作中， 已经合成了掺杂三种不同金属离子（Ce M、M = Y、La、Mo）的CeO ₂纳米粒子，其表现出显着提高的光还原 CO ₂活性。根据电子顺磁共振 (EPR) 和 X 射线光电子能谱 (XPS) 的分析，Y 和 Mo 掺杂导致 CeO _{2 中}氧空位浓度增加，这促进了紫外可见光的吸收以及电子和空穴的分离/转移，从而提高了催化活性。更重要的是通过在-原位FT-IR，CO ₂吸附/活化和CO中对催化剂表面生成的中间体₂光还原反应进行了研究，并进行了深入讨论。已发现在 CeO ₂和 Ce M上产生类似的碳酸盐和碳氢化合物，例如 HCO ₃ ^-、b-CO ₃ ^2-和 m-CO ₃ ^2-。，而这些积累并强烈覆盖在催化剂表面的中间体已被证明是导致 CO ₂还原活性和稳定性逐渐下降的原因。