Mechanochemical preparation method for the fabrication of the mesoporous Ni–Al2O3 catalysts for hydrogen production via acetic acid steam reforming

Abstract

Ni(x)-Al2O3 (x = 5, 7.5, 10, 12.5, 15, 17.5, and 20 wt%) catalysts were fabricated by the mechanochemical way, and the samples were used in acetic acid steam reforming. The results showed that all prepared samples have excellent features with a high BET area in the range of 185–215 m2 g−1. Based on the founding results, the reducibility degree of the studied samples was enhanced by raising the nickel content to 17.5 wt%. The activity results revealed that the catalyst with 17.5 wt% Ni showed the best performance, and the acetic acid conversion and hydrogen yield reached 93% and 35% at 450 °C over this sample, respectively. Also, the agglomeration of particles at higher calcination temperatures led to the decrease in acetic acid conversion by increasing the Tcalcination from 700 to 900 °C. Furthermore, the results demonstrated that the catalytic activity improved by a decrease in GHSV value from 24000 to 12000 ml h−1.g−1cat and an increase in the S/C molar ratio from 1:1 to 5:1. The influence of reduction temperature on the catalytic performance was also studied over the selected catalysts, and the results indicated that the sample under reduction temperature of 700 °C displayed the highest efficiency in the acetic acid steam reforming, which was related to the existence of more active sites and more acetic acid adsorption on the catalyst surface.