Wang Min, Shen Meng, Jin Xixiong, Tian Jianjian, Zhou Yajun, Shao Yiran, Zhang Lingxia, Li Yongsheng, Shi Jianlin
School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China.
Nanoscale. 2020 Jun 21;12(23):12374-12382. doi: 10.1039/d0nr00717j. Epub 2020 Jun 3.
The vacancy defects of semiconductor photocatalysts play key roles in enhancing their photocatalytic CO reduction activity. In this work, CeO was chosen as a model catalyst and oxygen vacancies were introduced on its surface by a facile and mild oxalic acid treatment followed by moderate heating in N. Such a treatment resulted in a much increased ratio of Ce/Ce in CeO, and the oxygen vacancy-enriched CeO showed remarkably enhanced photocatalytic activity in CO reduction, with CO being the dominant reduction product, whose yield was about 8 times that on the pristine CeO. In situ FT-IR spectra showed that the abundant oxygen vacancies substantially improved the CO adsorption/activation on the surface of CeO, which facilitated the subsequent reduction of CO. However, the carbonates strongly adsorbed on the photocatalyst surface might be the main obstacle to maintaining the high CO reduction activity and stability of CeO with O vacancies.
半导体光催化剂的空位缺陷在增强其光催化CO还原活性方面起着关键作用。在这项工作中，选择CeO作为模型催化剂，并通过简便温和的草酸处理，随后在N2中适度加热，在其表面引入氧空位。这种处理导致CeO中Ce3+/Ce4+的比例大幅增加，富含氧空位的CeO在CO还原中表现出显著增强的光催化活性，CO是主要的还原产物，其产率约为原始CeO的8倍。原位FT-IR光谱表明，大量的氧空位显著改善了CO在CeO表面的吸附/活化，这促进了随后的CO还原。然而，强烈吸附在光催化剂表面的碳酸盐可能是维持具有氧空位的CeO的高CO还原活性和稳定性的主要障碍。
