以获得具有经济价值的能源或化学品为目标的CO2化学转化，可实现 CO2 的资源化循环利用，是解决我国碳排放问题、实现碳中和目标的潜在路径。光催化技术相比传统的热催化，具有能耗低、反应条件温和等优势，是实现CO2能源化利用的理想方式之一。然而由于CO2极其稳定，导致反应转化率低。光催化CO2转化反应的核心是通过设计催化剂和反应体系，尽可能提高光催化剂的催化活性，进而提高CO2还原产物的选择性和产率。基于现阶段对光催化CO2转化技术需求的紧迫性，及时全面了解近几年该领域的研究进展有助于合理分析未来研究方向。主要从光催化还原CO2反应技术优势、反应机理、催化剂种类和最新研究成果等方面综述了光催化CO2转化利用的研究进展。详细阐述了光催化体系的组成、CO2得电子的还原过程和目前CO2光催化转化产物产量规模及影响产物选择性的因素，重点探讨提高光催化反应转化率的策略，包括引入贵金属助催化剂、构建异质结结构、挖掘新型光催化剂、构建促进电子传递通道和电/热催化与光催化的耦合等。结果表明，上述策略均可不同程度提高CO2转化反应的转化率，还原产物种类也从C1产物逐渐发展到C2产物，其中光电/光热催化相较于单独光催化具有更高的转化率，这使得光催化CO2转化技术在未来应用的可能性得以提升。此外，指出了当前光催化CO2能源化利用方面存在的不足，如转化效率低、产物选择性差和无法实现高附加值产物的可控合成等，对光催化实现CO2能源化利用的研究重点，即高效光催化剂的开发、催化过程动力学反应机理进行了展望。

Aimed at obtaining economically valuable fuels or chemicals,the chemical conversion of CO2 provides a renewable utilization route for CO2,which is one of the most promising alternatives to solve current carbon emission issue and achieve CO2 neutrality. Compared with traditional thermocatalysis,photocatalytic technology has the advantages of low energy consumption and mild reaction conditions,and is one of the ideal solutions to realize the energy utilization of CO2. However,owing to the chemical stability of CO2,the conversion reactions that convert CO2 are relatively low. The research core of photocatalytic CO2 reduction is to improve the catalytic activity of photocatalysts through the design of catalyst and reaction system so as to improve the selectivity and controllability of the CO2 reduction products. Due to the urgency of photocatalytic CO2 conversion technology at the present stage,a timely and comprehensive understanding of the research progress in this field in recent years is helpful to reasonably analyze the possible research direction in the next stage. The research progress of photocatalytic CO2 reduction was reviewed from the advantages of photocatalysis,reaction mechanism,catalysts and the latest research results. The composition of the photocatalysis system,the electron reduction process of CO2,and the current products of CO2 photocatalytic conversion,yield,scale and factors affecting the selectivity of products were described in detail. The strategies to improve the reduction performance were mainly elaborated,including the introduction of noble metals co-catalysts,the construction of heterojunction structure,exploring  new photocatalysts,the construction of electron transport channel and coupling of electric or thermal catalysis with photocatalysis,etc. The results show that the above strategies can improve the conversion rate of CO2 reduction reaction in varying degrees,and the types of reduction products gradually develop from C1 to C2. Notably,photoelectric/photothermal catalysis has a higher conversion rate than photocatalysis alone,which improves the possibility of future application of this technology and deserves much research and attention. In addition,it is pointed out that the current photocatalytic reduction of CO2 has problems of insufficient conversion efficiency,poor product selectivity,and unable to achieve controllable synthesis of high value-added products,etc. Future research should focus on the development of high-efficiency photocatalysts and the catalytic kinetics.

0 引言

1 光催化CO2还原反应机理

2 光催化还原CO2体系重要参数及性能提升策略

   2.1 催化剂

   2.2 催化剂改性方法

   2.3 还原产物的产量和选择性

   2.4 电/热助光催化还原CO2

3 结论