Unraveling the structure–sensitivity of the photocatalytic decomposition of N2O on CeO2: a DFT+U study. Issue 39 (1st October 2018)

• Record Type: Journal Article
• Authors: Song, Weiyu; Wang, Lu; Gao, Yang; Deng, Jianlin; Jing, Meizan; Zheng, Huiling; Liu, Jian; Zhao, Zhen; Gao, Manglai; Wei, Yuechang
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 39(2018)
• Page Start: 19241
• Page End: 19255
• Publication Date: 2018-10-01
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8ta06372a
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The photocatalytic activity of N2 O dissociation on CeO2 strongly depends on the exposed surface termination, with the (110) surface being much more reactive than the (111) surface. Abstract : The photocatalytic activity of N2 O dissociation on CeO2 strongly depends on the exposed surface termination, with the (110) surface being much more reactive than the (111) surface. However, the physical nature requires a more detailed molecular level study. Using the DFT+U method, in the present study, we intend to explore the influence of surface termination from the following three aspects: the optical absorption, transfer kinetics of electron polaron, and the photo-chemical reaction process based on comparative studies of CeO2 (111) and (110) model surfaces. Due to the large band gap value, both CeO2 surfaces show negligible optical absorption difference. For both surfaces, the electron polaron is preferably localized on the surface rather than in the bulk. The Ce 3+ ion close to the oxygen vacancy repels the excited electron due to Coulomb interactions. The migration barrier of the electron polaron from the bulk to the surface on the (110) surface is slightly lower than that on the (111) surface, suggesting a higher transfer rate of the electron polaron. The dissociation process of N2 O into N2 with and without the photoexcited electron on CeO2 (110) and (111) surfaces is explored. On the stoichiometric CeO2 surface, N2 O decomposition is difficult due to the inhibitive high reaction energy. In contrast, the reaction energy dramatically decreases in the presence of photoexcited or excess electrons on the CeO2 surface. The reaction energy is related to the electronic state of dissociated O. More negative charges make O more stable and accordingly lead to higher exothermic reaction energy.