Preparation of Lanthanum–Nickel–Aluminium Perovskite Systems and their Application in Methane-Reforming Reactions

In this study we developed LaNixAl1-xO3 perovskite systems using a sol-gelmethod (with propionic acid as solvent) to use in methane-reforming reactions for producing synthesis gas. To understand the roles of the nature of the precursor and calcination conditions on the formation of LaNixAl1-xO3, we carried out identifications using NMR, FT-IR, XRD, SEM, and TEM. The precursor structure is a function of raw materials and calcination conditions. Nitrate salts of nickel, aluminium, and lanthanum, and calcinations at 750ºC for 4 h gave pure LaNixAl1-xO3 perovskite with good homogeneity, even at nanoscopic scales. These systems are highly efficient catalysts in steam and the dry reforming of methane. Various ratios of hydrogen to carbon monoxide in synthesis gas can be achieved by changing the feed type. We also investigated stabilization of these systems by studying the perovskite structure after reactivity tests. The optimum mixed perovskite for steam and dry reforming of methane is LaNi0.3Al0.7O3. The total conversion of CH4 is rapidly obtained at 750°C in steam reforming with a H2O/CH4 ratio = 3, the selectivity of CO is lower (55%) and the yield of hydrogen (98%) is higher compared to the ratio H2O/CH4 = 1. After 170 h of reaction, no deactivation had occurred, methane conversion remained higher than 90% at 750°C and in dry reforming, methane conversion and CO yield are about 98% and 95% respectively.