CO2 hydrogenation to methanol over Cu/CeO2 and Cu/ZrO2 catalysts: Tuning methanol selectivity via metal-support interaction

• Published in: Journal of energy chemistry 2020-01, Vol.40, p.22-30
• Main Authors: Wang, Weiwei, Qu, Zhenping, Song, Lixin, Fu, Qiang
• Format: Article
• Language: English
• Subjects: CeO2; CO2 hydrogenation; In-situ DRIFTS; Methanol selectivity; ZrO2
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2019.03.001

Copper-based catalysts for CO2 hydrogenation to methanol are supported on ZrO2 and CeO2, respectively. Reaction results at 3.0 MPa and temperatures between 200 and 300 °C reveal that Cu catalysts supported on ZrO2 and CeO2 exhibit better activity and selectivity than pure Cu catalyst due to Cu-support (ZrO2 and CeO2) interaction. Combining the structural characterizations with in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS), Cu/CeO2 shows the higher methanol selectivity due to the formation of main carbonates intermediates, which are closely related with the oxygen vacancies over Cu/CeO2. In contrast, bicarbonate and carboxyl species are observed on Cu/ZrO2, which originates from the hydroxyl groups presented on catalyst surfaces. Difference in CO2 adsorption intermediates results in the distinct methanol selectivity over the two catalysts. The difference in metal-support interaction over Cu/CeO2 and Cu/ZrO2 leads to different reaction pathways. The former abides by HCOO route while the latter follows COOH route, and then produces different methanol selectivities. [Display omitted]