Synergistic promotion of phenol hydrogenation by regulating specific surface area and oxygen vacancies based on the morphology dependent effect
Abstract
The development of highly efficient catalysts to promote sustainable production of value-added chemicals from biomass remains a significant task. This work reports a strategy to accelerate the selective hydrogenation of phenol to cyclohexanol over Ni-based catalysts by modulating the concentration of oxygen vacancy and specific surface area of CeO2 supports. Ni@C/CeO2-F catalyst with a flower-like morphology achieved the best catalytic performance with 92.5?% phenol conversion and 100?% cyclohexanol selectivity compared with Ni@C/CeO2-R (50.2?%) and Ni@C/CeO2-C (57.6?%) catalysts at 140 ℃, 2?MPa, 2?h. Characterization results indicate the superior catalytic performance of Ni@C/CeO2-F catalyst mainly originated from its unique flower-like structure with a high content of oxygen vacancies (OVs), large specific area as well as the uniform dispersion of Ni active sites. Density functional theory (DFT) calculation results further confirm the existence of OVs can enhance the adsorption ability of the phenol, improve electron transfer rate and reduce reaction energy barrier, contributing to the improved catalytic performance. In addition, a negligible decline in catalytic performance after 5 successive cycles reveals the outstanding recyclability of Ni@C/CeO2-F catalyst.