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

Ni/La–Al 2 O 3 and Ni/Ce–Al 2 O 3 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 pre-reforming. 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 Ni–Al 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. [Display omitted] • Ni/Al 2 O 3 and Ni/M/Al 2 O 3 (M = La or Ce) were tested in methane steam reforming. • Catalytic activity was evaluated both in the kinetic and diffusion regime. • The promoters increased the catalytic activity at kinetic regime almost twice. • An effect of additives was not confirmed in diffusive regime. • The addition of La 2 O 3 caused a significant increase in resistance to coking. [ABSTRACT FROM AUTHOR]