Cold plasma dielectric barrier discharge reactor for dry reforming of methane over Ni/ɤ-Al2O3-MgO nanocomposite

Abstract

Dry reforming of methane (DRM) to syngas in a dielectric barrier discharge (DBD) plasma reactor over Ni-loaded ɤ-Al2O3-MgO nanocomposite catalysts has been investigated. The catalysts are prepared by modified incipient wetness impregnation method, assisted by cold plasma treatment. The samples are characterized by XRD, N2 adsorption-desorption, H2-TPR, CO2-TPD, FESEM and EDX. The performance of the catalyst for DRM is evaluated at various specific input energy (SIE J ml−1) and gas hourly space velocity (GHSV, h−1). The maximum conversion achieved are 74.5% and 73% for CH4 and CO2 respectively, over 10% Ni/ɤ-Al2O3-MgO at specific input energy (SIE) = 300 J ml−1 and gas hourly space velocity (GHSV) = 364 h−1. The main reaction products are H2 (29.5%), CO (30.5%) with H2/CO = 1 inferring RWGS reaction is suppressed for 12 h operation time. The enhanced conversion and yield are due to the strong metal-support interaction, high Lewis basicity and stable 10% Ni/ɤ-Al2O3-MgO catalyst as well as the plasma-catalyst interface. The energy efficiency (EE) of the plasma-catalytic DRM is higher (0.117 mmol kJ−1) compared to plasma only (0.087 mmol kJ−1) demonstrating the synergy between catalyst and plasma. The reaction mechanism is also proposed to postulate the steps involved in the DRM.