Novel LaNi intercalated Egyptian bentonite clay for direct conversion of methane using CO2 as soft oxidant

Abstract

Natural Egyptian bentonite clay intercalated with both La and Ni having different molar ratio (La: Ni = 2:1, 1:1 & 1:2) were prepared, saving 5mmole pillar/gm clay, using ultrasonic assistance method. The prepared catalysts were calcined at 450 and then reduced at 400 °C & 600 °C.Characterization of the prepared LaNi-PILC was achieved by X-ray diffraction (XRD), Furrier transform infrared spectroscopy (FTIR), N2 adsorption desorption isotherm (BET) and H2-temperature programmed reduction (H2-TPR). The data confirm the success of intercalation process for both La & Ni in the lamellar structure of bentonite clay. The La: Ni molar ratio affected the specific surface area, Ni crystal size, dispersion and reducibility of the prepared catalyst. The reduction temperature had a great effect on the reactivity and product selectivity during CO2/CH4 reforming at different reaction temperatures (600–800 °C). Where, reduction at 400 °C gives rise to CH4 oxidation reaction (MOR) with formaldehyde as a main product. While reduction at 600 °C enhances the activity and stability for CO2 reforming of methane (CRM) and syngas production (H2/CO ~ 1.19). The most active and stable LaNi1:2-PILC5 catalyst (CO2 and CH4 conversions reached 85% and 90% respectively) is superior with respect to the performance of PILC based catalysts reported in the literatures.