Ni/Al2O3-La2O3 catalysts synthesized by a one-step polymerization method applied to the dry reforming of methane: effect of precursor structures of nickel, perovskite and spinel

摘要

Ni catalysts supported on alumina with various lanthanum contents were prepared by the one-step polymerization method to form catalytic precursors that allow better dispersion of the active nickel metal and improve the Ni-La interaction in catalysts containing Ni, Al and La. The characterization of the materials was performed by XRD analysis, N-2 adsorption-desorption, H-2-temperature programmed reduction, CO2 and H-2-temperature programmed desorption and scanning electron microscopy. The catalytic tests were conducted over a period of 6 h and with a stoichiometric ratio of CH4:CO2 equal to 1. The addition of lanthanum in the catalysts led to the formation of LaNiO3 and LaAlO3 perovskites, with a significant reduction of the specific surface area. The catalysis without the presence of lanthanum (NiAl) presented higher methane conversion during the catalytic test but the NiAlLa0.5 catalyst showed highest catalytic activity when considered the number of active sites exposed for reaction. In addition, it was observed that the formation of LaNiO3 perovskite reduces the sintering of the active phase, increasing the degree of dispersion of the catalysis and provides better Ni-La interaction in dry reforming of methane.