The effect of La2O3 and CeO2 modifiers on properties of Ni-Al catalysts for LNG prereforming

Ni/La-Al2O3 and Ni/Ce-Al2O3 catalysts with a small amount of promoters intended for prereforming of LNG were characterized by XRF, N-2 adsorption-desorption, XRD, H-2 chemisorption, HRTEM and XPS. The catalytic activity was evaluated in methane steam reforming both in the kinetic and diffusion regime, at temperatures characteristic of prereforming. Carbonaceous deposit was analysed by TPO-MS method. The nature and location of the coke were studied by HRTEM. La or Ce addition into Ni-Al system causes the increase of the active surface area of Ni by enhancing its dispersion. Studies at kinetic regime have shown that the promoted catalysts have almost twice the activity than reference NieAl catalyst. This effect was not confirmed by measurements in the diffusion regime on whole catalyst tablets. Almost identical textural properties of catalysts and diffusive limitations related to them but not the catalytic properties of the material itself appeared to be crucial factors. The presence of La (but not Ce) causes a significant increase in resistance to coking. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

Ni/La-Al2O3 and Ni/Ce-Al2O3 catalysts with a small amount of promoters were characterized and evaluated for methane steam reforming. The addition of La or Ce into Ni-Al system increased the active surface area of Ni and resistance to coking. While the promoted catalysts showed higher activity in the kinetic regime, this effect was not observed in the diffusion regime.