State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology
Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering

CO2资源化利用是实现“碳达峰碳中和”目标不可或缺的环节。将CO2催化转化为甲酸是一种有效且最为原子经济的路径，但因CO2热力学性质稳定，导致其不易活化，反应转化率低。为了在温和条件下得到更高的甲酸产率，将光催化与热催化结合。光热催化主要体现在光活化上，通过激发载流子，调控电子注入位置和吸附位点有效活化CO2，热能则增强反应物CO2的吸附、电荷转移和反应速率，激活热活性位点，结合光催化的低能耗、反应条件温和与热催化高效率的优势提高甲酸产率及选择性。目前，光热催化CO2还原制甲酸的主要挑战在于CO2固有的化学稳定性使得CO2转化率低、产物不可控、选择性差等。基于目前对光热催化CO2转化技术的需求，分别介绍了光催化、热催化、光热催化的原理、优势及存在的问题，重点从催化剂改性、反应条件、反应器选择方面综述了光热催化CO2还原制甲酸过程中提高CO2转化率和甲酸选择性的策略，其中重点探讨对于催化剂的改性，包括提高电子−空穴分离程度、调控暴露面比例以及提高CO2的吸附，并阐述了光热催化CO2还原制甲酸需重点攻克的问题。未来研究应综合考虑反应器选择与催化剂设计，通过反应条件的优化，实现高产率甲酸的生产以及光热催化大规模工业应用。

CO2 utilization as resource is an indispensable part to achieve the goal of “carbon peaking and carbon neutrality”. Catalytic conversion of CO2 to formic acid is an effective and most atomic economically viable route. However, due to the stable thermodynamic properties of CO2, it is difficult to be activated and the conversion rate of above reaction is generally low. In order to obtain a higher formic acid yield under mild conditions, photocatalysis is combined with thermal catalysis. Photothermal catalysis is mainly reflected in photoactivation, which effectively activates CO2 by stimulating carrier, regulating electron injection location and adsorption site. Thermal energy could further enhance the adsorption rates of CO2, charge transfer and reaction, and activate the thermally active sites, which could improve the yield and selectivity of formic acid by combining the advantages of low energy consumption of photocatalysis and high efficiency of thermal catalysis. At present, the main challenge of photothermal CO2 reduction to formic acid is the inherent chemical stability of CO2 which results in a low CO2 conversion rate, uncontrollable product and poor selectivity etc. Considering the current demand for the photothermal catalytic CO2 conversion technology, this study introduced the principles, advantages and disadvantages of photocatalysis, thermal catalysis and photothermal catalysis. The strategies for improving CO2 conversion and formic acid selectivity were reviewed from the aspects of catalyst modification, reaction conditions and reactor selection. The modification methods of catalyst were mainly elaborated, including the improvement of electron-hole separation degree, the regulation on the proportion of exposed surface and the improvement on the adsorption of CO2. The key problems of photothermal CO2 reduction to formic acid were described in detail. In future studies, the production of high-yield formic acid and large-scale industrial application of photothermal catalysis can be realized by optimizing the reaction conditions and comprehensively considering the reactor selection and catalyst design.

中央高校基本科研业务费专项资金资助项目(2022ZFJH004)；国家重点研发计划资助项目(2022YFE0208400)；山西浙大新材料与化工研究院研发资助项目(2021SX-FR002)

高慧敏，荆洁颖，李文英. 光热催化CO2还原制甲酸研究进展[J]. 煤炭学报，2023，48(7)：2760−2772.

GAO Huimin，JING Jieying，LI Wenying. Research progress on photothermal catalytic CO2 reduction to formic acid[J]. Journal of China Coal Society，2023，48(7)：2760−2772.