CO2-assisted fast pyrolysis of palm kernel shells over a Ni–Ce/CN catalyst for the selective production of bio-oil.

[Display omitted] • CO 2 assisted fast pyrolysis of palm kernel shells. • Ni-Ce/CN50 catalyst enhanced oxygen removal efficiency. • High potential use of NiCe/CN50 catalyst for phenol production. • The presence of Ce reduced coke formation. Catalytic fast pyrolysis is one of the most promising techniques for the production of bio-oils. Generally, pyrolysis is carried out in an inert atmosphere; however, reactive catalytic pyrolysis has emerged as an alternative technique for achieving high catalytic efficiency. Herein, NiCe/CN catalysts with different Ni:Ce ratios were developed, and their catalytic efficiency in the catalytic fast pyrolysis of palm kernel shells in a CO 2 atmosphere was evaluated. The effects of reaction conditions, including the reaction temperature (400–600 °C) and ratio of Ni:Ce (10:0, 10:1, 10:3, 10:5, and 10:10), on the product yields were studied using in situ and ex situ analyses. NiCe/CN50 exhibited enhanced oxygen removal efficiency owing to the presence of oxygen vacancies in CeO x. In addition, the acidic site of the catalyst promoted the highly selective demethoxylation of alkylphenols. The presence of Ce promoted the Boudouard reaction (C + CO 2 → 2CO), which reduced coke deposition on the spent catalyst. Our results indicate that the NiCe/CN50 catalyst exhibited good catalytic efficiency, achieving the highly selective production of alkylphenols and acetic acid and low deactivation. Therefore, NiCe/CN50 can be used as an alternative catalyst for phenol production from biomass via catalytic fast pyrolysis. [ABSTRACT FROM AUTHOR]