Abstract
CO2 photoreduction over CeO2 surfaces has been studied for a few years, and many efforts have been devoted to understanding the effect of exposed crystal facets and oxygen vacancies (OVs) on the catalytic activity. In this work, the formation of OVs over different CeO2 surfaces is investigated through X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electron paramagnetic resonance spectroscopy (EPR), revealing the facet-dependent OVsin CeO2. The experimental results and DFT calculations show that the OVs formed in (111)CeO2 and (100)CeO2 possess faster charge transfer and a more negative conduction band potential than (110)CeO2. The in-situ Fourier transform infrared spectroscopy (FTIR) and DFT results revealed the CO2 absorption, activation, and reduction processes over the three samples. Although (110)CeO2 surface shows the best adsorption capability for CO2, its catalytic activity is still limited by a high barrier (1.95 eV) in the formation of CO species from COOH* intermediate. Through the H2O-assisted CO2 activation process, (111)CeO2 and (100)CeO2 show better reduction activity for CO2, resulting in the better activity for CO2 photoreduction. This study demonstrates that the band structure and CO2 activation influenced by OVs show a strong crystal facet dependence in CeO2.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.