金属氧化物半导体用于光热催化CO_(2)加氢反应:最新进展和展望

Metal Oxide Semiconductors for Photothermal Catalytic CO_(2) Hydrogenation Reactions:Recent Progress and Perspectives

由于人类经济社会的快速发展,大气中二氧化碳的浓度逐年增加造成了严重的生态环境问题。为了应对气候变化带来的挑战,中国作出了“到2030年达到碳排放峰值,到2060年实现碳中和”的重大承诺。理想情况下,将二氧化碳转化为增值产品或太阳能燃料(如CH_(4)、CO)是一种两全其美的策略,可以同时缓解温室效应和解决能源供需不足的问题。在为上述策略提出的设想中,利用可再生的绿H2生产化学品来减少CO_(2)的方案是首选,它除了实现CO_(2)减排,还可以激发清洁能源的潜力。为了研究这一还原过程,人们设计了许多催化反应,其中光催化是最理想的方案,因为太阳能是清洁和可持续的。在光催化中,光热催化二氧化碳加氢技术因其较高的催化效率和太阳能的广泛利用而成为一种很有前途的CO_(2)转化方案。对光热催化加氢原理目前主要有两种解释:(1)仅以太阳光为能量源,驱动催化剂自身产热从而实现二氧化碳的转化。在这种情况下,反应仍以热催化方式进行。(2)光能与热能相互耦合协同催化反应的发生。因此,根据催化方式的不同,光热催化剂的合理设计和成功合成非常重要。值得关注的是,金属氧化物半导体由于其独特的能带结构和化学性质,高稳定性,环境友好等优点,被广泛应用于光热催化加氢反应的研究。在本文中,我们主要从负载催化剂、微观结构工程、缺陷工程三种不同的催化剂调控策略综述了金属氧化物材料用于光热催化CO_(2)加氢反应的研究进展,特别是近五年的重要研究成果。同时,对这些调制策略的机理进行了总结和介绍,以供进一步理解。本文还介绍了不同类型的光热加氢反应器,以及一些重要参数对催化反应的影响。最后,对金属氧化物催化剂的设计策略提出建议,并对光热减排技术的发展提出展望。

Owing to the accelerated growth of the human economy and society,the increasing concentration of CO_(2) in the atmosphere has caused serious ecological and environmental problems because of the greenhouse effect.In response to the challenges posed by climate change,China has made a significant commitment to“peak carbon emissions by 2030 and achieve carbon neutrality by 2060”.Ideally,converting CO_(2) into carbon-based energy and chemicals is supposed to be the best strategy of both worlds,mitigating the greenhouse effect while also addressing the shortage of energy supply.Among the proposed concepts for the above strategy,the scheme of reducing CO_(2) using renewable green H_(2) to produce chemicals is preferred,because it can stimulate the potential of clean energy while also reducing CO_(2) emission.To accelerate this reduction process,many catalytic reactions,including photocatalysis,have been designed and investigated.Owing to its high catalytic efficiency and extensive use of solar energy,photothermal catalytic CO_(2) hydrogenation in photocatalysis is desirable for increasing sun-to-fuel efficiency.There are two main interpretations of photothermal catalytic hydrogenation:(1)only sunlight is used as the energy source to drive the catalyst,which generates heat to promote CO_(2) conversion.In this case,the reaction still proceeds in the form of thermocatalysis,whereas photocatalysis has a limited effect.(2)Solar and heat energy are coupled to participate in the catalytic reaction,which has a synergistic effect.Therefore,according to the catalytic mode,the rational design and successful synthesis of photothermal catalysts are very important.Metal oxide semiconductors,owing to their unique energy band structure and chemical properties,high stability,and environmental friendliness,are widely used in the research of photothermal catalytic hydrogenation reactions.This paper reviews the research progress on metal oxide materials used in the CO_(2) hydrogenation reaction by photothermal catalysis.In particular,the most significant results of research in the last five years have been performed mainly from three different catalyst modulation strategies,such as supporting catalysts,applying microstructure engineering,and defect engineering.The mechanisms of these modulation strategies are summarized and presented for further understanding.In addition,this study introduces different types of photothermal hydrogenation reactors,accompanied by the effects of some key parameters on the reactions.Finally,design strategies for metal oxide catalysts are suggested,and an outlook of photothermal abatement technology is presented.