Hydrodeoxygenation of guaiacol over BEA supported bimetallic Ni-Fe catalysts with varied impregnation sequence

BEA supported Ni-Fe catalysts, prepared by various impregnation techniques, were characterised and examined for their activity for the hydrodeoxygenation (HDO) of guaiacol and hydrogenation of toluene. The aim of the study was to explore the factors affecting the formation of Ni-Fe active species and explore the relationship between the concentration of surface Ni, Ni-Fe species and HDO activity. Catalysts pre -pared initially with Fe, or co-currently with Fe and Ni exhibited a higher level of HDO rate compared to catalyst that was prepared with Ni initially. When a catalyst was impregnated initially with Fe, metal-supported interaction was relatively weak, thus the formation of Ni-Fe species was promoted. In contrast, a reduced number of Ni sites was involved in the formation of Ni-Fe species when the catalyst was ini-tially impregnated with Ni, resulting in a low HDO rate. The rate of cyclohexane formation is proportional to the concentration of surface Ni-Fe over the catalysts with similar Ni and Fe loadings but prepared by different impregnation sequences. The enhanced HDO rate is attributed to the hydrogenolysis activity of Ni-Fe species. The effect of Ni/Fe ratio on HDO activity was also investigated under differential conditions and the catalyst with a Ni/Fe mass ratio of 3.3 exhibited the highest rate of cyclohexane formation. (c) 2021 Published by Elsevier Inc.

Automated summary

Ni-Fe catalysts prepared by different impregnation techniques were studied for their activity in the hydrodeoxygenation of guaiacol and hydrogenation of toluene. The study found that the ratio of Ni/Fe significantly influences the hydrodeoxygenation activity, with a catalyst having a Ni/Fe mass ratio of 3.3 exhibiting the highest performance.