Mechanistic Study on the Photothermal Catalytic Synthesis of Dimethyl Carbonate from CO ₂ and CH ₃ OH over Fe-, Co-, and Ni-Doped ZrO ₂ (101) Surfaces

Zr-based catalysts for the photothermal catalysis of CO2 and CH3OH to DMC represent a significant area of research. However, the catalytic mechanism of the photothermal cooperation process remains poorly understood. This work employs density functional theory (DFT) to comprehensively explore the impact of M (Fe, Co, and Ni) doping on the surface properties of tetragonal ZrO2-x(101) and the photothermal catalysis pathway for CO2 synthesis of dimethyl carbonate (DMC). Differential charge density and density of states calculations demonstrate that Co–O–Zr sites induce the strongest electron localization, which is key to performance enhancement. First, CH3OH is oxidized by photogenerated holes to *CH2OH, while *CO2 reacts to generate *CH3OCOO. Thereafter, *CH3OCOO decomposes to form the *CH3OCO species, and CH3O* (under thermal catalysis) couples with *CH3OCO to form DMC. The Co doping reduces the rate-controlling energy barrier (*CH3OCO + *CH3O → DMC, 175.7 kJ/mol → 138.1 kJ/mol), facilitating the generation of DMC. Additionally, M-doped tetragonal ZrO2-x was synthesized via the hydrothermal method, demonstrating an increase in DMC yield from 6.14 mmol/g to 7.36 mmol/g under photothermal conditions, which proves the correctness of the theory. This study provides a comprehensive understanding of the mechanism of photothermal synthesis of DMC on Fe, Co, and Ni-doped ZrO2-x(101) and offers valuable guidance for the rational design of high-performance ZrO2 catalysts.