Dry reforming of methane over Ni/dendritic fibrous SBA-15 (Ni/DFSBA-15): Optimization, mechanism, and regeneration studies

Dendritic fibrous type SBA-15 (DFSBA-15) was recently discovered with its outstanding catalytic performance and coke resistance as compared to the conventional SBA-15. The operating conditions for dry reforming of methane (DRM) over 10Ni/DFSAB-15 were optimized by using response surface methodology (RSM), followed by stability and regeneration study. Characterization results (TEM and FESEM) confirmed the homogenous distribution of Ni0 particles with no morphological change in spherical DFSBA-15 upon Ni addition. Process parameters, such as reaction temperature (X-1, 700 degrees C-900 degrees C), gas hourly space velocity (X-2, 15,000 mL/g.h - 35,000 mL/g.h), and CH4/CO2 ratio (X-3, 1-3) were studied over CO2 conversion (Y-1), CH4 conversion (Y-2), and H-2/CO ratio (Y-3). The optimal reaction conditions were found at X-1 = 794.37 degrees C, X-2 = 23,815.022 mL/g.h, and X-3 = 1.199, with Y-1 = 95.67%, Y-2 = 93.48%, and Y-3 = 0.983. The in-situ FTIR studies of adsorbed CH4, CO2, and CH4 + CO2 confirmed the formation of unidentate carbonate, bidentate carbonate, and linear carbonyl species as intermediate species. 10Ni/DFSBA-15 presented good reproducibility by using both regeneration medium (air and CO2/N-2) with two-fold regeneration by air as compared to CO2/N-2. It was proven that the synthesized 10Ni/DFSBA-15 was appreciably stable and prone to be regenerated by air for DRM under optimal conditions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.