Effects of alkali and alkali-earth metals in catalyst of methane reforming

CO2 reforming of CH4 to syngas was studied over Mixed perovskite oxides with MxLa1- xNi0.3Al0.7O3-d (M= Ca, Sr, Na, K; X= 0, 0.2, 0.5, 0.8 and 1.0) component have been prepared by a sol-gel method with propionic acid as solvent and calcinations at 750ºC for 4 hours. The perovskite type oxide characterized by X-ray diffraction (XRD) analysis that showed single phase perovskite-type solid solutions for all samples except X=1, temperature programmed reduction (TPR), Scanning electron microscopy (SEM) coupled to an energy dispersive X-ray spectrometer (EDS). Characterization of samples has been studied to evaluate the pure homogeneity structure of the catalyst. The experimental results showed that the series of perovskite MxLa1-xNi0.3Al0.7O3-d catalyst gave the high activity. Conditions for methane reforming was attained under 800°C, atmospheric pressure, and CO2/CH4 = 1, and the composition of syngas formed was almost H2/CO= 1. Carbon deposition was no observed, and the catalytic activity and the syngas selectivity were stable for 15 hours over all catalysts. Among the samples, Sr0.2La0.8Ni0.3Al0.7 showed with a good resistance to coke formation, an excellent catalytic performance afforded 98% conversion of methane to give CO and H2 with the selectivity of above 85% at 800 ºC.

Keywords:

Perovskite , Reforming , Syngas , Alkali , Alkali-earth