Synergetic catalysis of NiOx with oxygen vacancies and Ni2P for highly efficient hydrodeoxygenation of phenolic compounds

Yunhua Li; Yafei Zhao; Binghui Chen; Wenju Wang

Index: 10.1002/cctc.201800010

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Abstract

High efficient hydrodeoxygenation of oxygenated chemicals at low temperature is a critical issue for biomass crude oil upgrading to reduce equipment and operation expenses. Unique electronic features of oxygen vacancies have been found to facilitate occurrence of deoxygenation above 250°C. In this work, firstly a series of NiOx/SiO2 catalysts containing some oxygen vacancies were prepared by sol‐gel and controllable temperature‐programmed reduction method. Results show that NiOx/SiO2 has superior phenol hydrogenation activity to deoxygenation even at 180°C, which was contrary to Ni2P/SiO2. High hydrogenation activity derives from flat adsorption of phenolics over low valence Ni cations induced by connected oxygen vacancies. As introducing NiOx into Ni2P catalysts, composite NiOx‐Ni2P/SiO2 (0.43≤x<1) bifunctional catalysts demonstrate excellent phenol HDO performances under mild reaction conditions in comparison with individual Ni2P and NiOx catalysts and most of results from literatures because the coexistence of oxygen vacancies from NiOx and acid induced by Ni2P results in synergistic effect of adsorption configuration and hydrodeoxygenation ability, Besides, this composite catalyst also has a high activity for hydrodeoxygenation of different bio‐derived cresol isomers. The reuse test result confirms that oxygen vacancies are relatively stable in comparison with phosphide.