催化学报 ›› 2020, Vol. 41 ›› Issue (1): 131-139.DOI: 10.1016/S1872-2067(19)63393-0

• 光催化CO2还原 • 上一篇    下一篇

光致热效应促进的全光谱光催化CO2还原

汪弘嘉a,b, 王艳杰a, 郭令举a, 张雪华a, Caue Ribeiroc,d, 贺涛a,b   

  1. a 国家纳米科学中心, 中国科学院纳米科学卓越创新中心, 中国科学院纳米系统和多级次制造重点实验室, 北京 100190, 中国;
    b 中国科学院大学, 北京 100049, 中国;
    c 巴西农牧业研究院, 国家农业纳米技术实验室, 圣卡洛斯 13561-206, 巴西;
    d 尤利希研究中心, 能源与气候研究所, 电化学过程工程室, 尤利希 52425, 德国
  • 收稿日期:2019-04-12 修回日期:2019-05-05 出版日期:2020-01-18 发布日期:2019-10-22
  • 通讯作者: 贺涛
  • 基金资助:
    中国科学院国际伙伴计划(一带一路)项目;国家自然科学基金(21673052,11404074).

Solar-heating boosted catalytic reduction of CO2 under full-solar spectrum

Hongjia Wanga,b, Yanjie Wanga, Lingju Guoa, Xuehua Zhanga, Caue Ribeiroc,d, Tao Hea,b   

  1. a CAS Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China;
    b University of Chinese Academy of Sciences, Beijing 100049, China;
    c National Nanotechnology Laboratory for Agribusiness, Embrapa Instrumentation, 13561-206, São Carlos-SP, Brazil;
    d Forschungszentrum Jülich GmbH-Institute of Energy and Climate Research-IEK-3/Electrochemical Process Engineering, Jülich 52425, Germany
  • Received:2019-04-12 Revised:2019-05-05 Online:2020-01-18 Published:2019-10-22
  • Supported by:
    This work was supported by the Belt and Road Initiative by Chinese Academy of Sciences and the National Natural Science Foundation of China (21673052, 11404074). Supporting Information associated with this article can be found in the online version, including EDX and XPS spectra of Au/rutile and rutile samples, and the plots used to determine Ea.

摘要: 以半导体等为催化剂,在太阳能作用下将CO2和H2O转化为可再生燃料与氧气的“人工光合作用”有望同时解决目前面临的严峻能源和环境问题,因而备受关注.但半导体催化剂光谱响应范围较窄、表面反应动力学缓慢,从而导致目前仍无法获得可观的太阳能-燃料转换效率.已有很多研究采用了晶面调控、元素掺杂和异质结构建等方法,以提高半导体光催化剂的太阳能-燃料转换效率,但效果仍不令人满意,主要原因是半导体光催化剂很难在吸收带边-氧化还原能力和活性-稳定性这两种关系中取得较好的平衡.此外,光催化反应中的动力学也是主要问题之一,尤其在人工光合作用反应中,CO2还原半反应和H2O氧化半反应的动力学均较困难,这已成为共识,而解决这个问题,将有助于我们从一新的角度理解光催化过程,从而提升光催化反应性能.
本文以Au NP/金红石为模型催化剂,纯金红石为参照,证明了存在太阳光中的红外光致热和可见光诱导的等离激元热效应等两类光致热效应,它们均可以促进人工光合作用反应.研究发现,人工光合作用反应与其他许多化学反应一样,表观活化能为正,从而表明动力学因素在该反应中起着重要作用.此外,根据不同反应温度下的结果,通过计算Au NP/金红石和纯金红石上生成CO和CH4的表观活化能,发现在这二种样品上CH4的表观活化能均高于CO,这就从动力学上解释了热力学上更容易得到的CH4在绝大多光催化CO2还原反应中的产率均低于CO.此外,无论是对于CO还是CH4,Au NP/金红石的催化表观活化能均低于纯金红石的.因此,本文从实验上提供了贵金属纳米粒子改善人工光合作用动力学的实验证据,并从动力学角度解释了人工光合作用反应中的活性和选择性问题.本研究证明了动力学因素在光催化反应,尤其是人工光合作用反应中的重要性,并提出了从动力学角度提升人工光合作用反应的新方法,即利用太阳光的光致热效应加速反应,这不仅有助于提升太阳能转化效率,也有望减少反应设备成本,从而促进其大规模应用.

关键词: CO2还原, 表观反应活化能, 反应动力学, 光致热效应, 光-热协同效应

Abstract: Catalytic converting CO2 into fuels with the help of solar energy is regarded as 'dream reaction', as both energy crisis and environmental issue can be mitigated simultaneously. However, it is still suffering from low efficiency due to narrow solar-spectrum utilization and sluggish heterogeneous reaction kinetics. In this work, we demonstrate that catalytic reduction of CO2 can be achieved over Au nanoparticles (NPs) deposited rutile under full solar-spectrum irradiation, boosted by solar-heating effect. We found that UV and visible light can initiate the reaction, and the heat from IR light and local surface-plasmon resonance relaxation of Au NPs can boost the reaction kinetically. The apparent activation energy is determined experimentally and is used to explain the superior catalytic activity of Au/rutile to rutile in a kinetic way. We also find the photo-thermal synergy in the Au/rutile system. We envision that this work may facilitate understanding the kinetics of CO2 reduction and developing feasible catalytic systems with full solar spectrum utilization for practical artificial photosynthesis.

Key words: CO2 reduction, Apparent activation energy, Reaction kinetics, Solar heating, Photo-thermal synergy