Highly active Ni/CeO2 for the steam reforming of acetic acid using CTAB as surfactant template

A series of CTAB-templated Ni/Ce catalysts were synthesized by adding CTAB during the hydrothermal synthesis of ceria to improve the pore structure of catalysts. Their catalytic performance was evaluated in the steam reforming of acetic acid and the effects of CTAB concentration on the porous structures, reducibilities, morphology, and activity of catalysts were studied. The catalysts were characterized by BET, XRD, H-2-TPR, XPS, HRTEM, insitu DRIFTS, DTG, FTIR, and temperature-programmed reaction to elucidate the structure-activity relationship of the catalyst. The results showed that owing to the CTAB assistance, a high surface area of ceria could be achieved, which induced a better Ni dispersion with a smaller Ni size, strengthened the interaction between Ni and CeO2, and promoted the reducibility of Ni, obtaining higher activity and lower methane yield than Ni/Ce. Among these prepared samples, Ni/Ce-C6 showed the highest surface area and the best catalytic performance with a hydrogen yield of up to 82.5% even at a low temperature (550 degrees C). Owing to the stronger Ni-ceria interaction of Ni/Ce-C6, the lattice oxygen in ceria migrates easily to the Ni surface, interacts with the reaction intermediates, and thus improves the CO2/CO ratio in the products. Much more CO and CO2 and less CH4 were observed over Ni/Ce-C6 during the temperature-programmed reaction, indicating its high activity. In-situ DRFITS characterization demonstrated that the two types of catalysts had similar reaction intermediates but various adsorption and conversion abilities toward the acetic acid. More reaction intermediates were adsorbed at low temperatures and a higher conversion was obtained over Ni/Ce-C6 owing to its better Ni dispersion. The CTAB assistance inhibited the formation of amorphous carbon but facilitated the formation of graphitic carbon at similar to 637 degrees C which did not induce catalyst deactivation. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, a series of Ni/Ce catalysts were synthesized with the assistance of CTAB, and their performance was evaluated. The results showed that CTAB improved the pore structure and reducibility of the catalysts, leading to higher activity and lower methane yield. Among them, Ni/Ce-C6 catalyst exhibited the best performance with high surface area and hydrogen yield, along with strong Ni-ceria interaction. Additionally, the CTAB assistance inhibited the formation of amorphous carbon.