Oxy-CO2 reforming of CH4 on Ni-based catalysts: Evaluation of cerium and aluminum addition on the structure and properties of the reduced materials

Abstract

Perovskites with the structural formula La1-xCexNi1-yAlyO3 (x = 0 y = 0; x = 0.05 y = 0; x = 0.05 y = 0.2 and x = 0.05 y = 0.5) were studied in the dry methane reforming in presence of oxygen or Oxy-Dry (OD). The materials were synthetized by the amorphous citrate method and characterized by XRD, in situ XRD under hydrogen and reactional (OD) atmospheres, TPR-H2, XRF, TPSR-OD, TPSR−CH4, TEM, HRTEM and TPO techniques. The catalytic performance was evaluated during 16 h of reaction, with a [CH4/CO2/O2] ratio = 4:2:1, at 800 °C and spatial velocity of 210.000 NL.h−1.kgcat−1. The addition of aluminum and cerium promoted an increase in the catalyst resistance to carbon poisoning, however, the higher the aluminum content was, the lower the reducibility of the perovskites and the nickel particle size. The La0.95Ce0.05Ni0.5Al0.5O3 sample showed the best results, with a maximum CH4 and CO2 conversion of 85 % and 86 % respectively and the higher syngas yield (45 % for CO and 48 % for H2). This sample presented the lowest Ni° particle size and carbon deposition after 16 h time on stream. No sign of deactivation was found for all the studied catalysts, showing the superior properties of catalysts prepared through perovskite-like mixed oxides.