Oxygen-rich ultramicroporous activated carbon for boosting H2 production via toluene steam reforming: Effect of H2O2-modification and Ni/Co loading

Abstract

The development of sustainable materials to produce a highly stable and efficient tar removal catalyst is important for biomass gasification technology. In this study, the effect of support modification using hydrogen peroxide (H2O2) and Ni and/or Co loadings on catalytic performance over palm kernel shell-based activated carbon (AC) supported catalysts for hydrogen (H2) production via steam reforming of toluene as biomass tar model compound have been investigated. The H2O2-modified AC (ACP) registers enhanced surface oxygenated functional groups and ultramicroporosity leading to highly dispersed active metals sites with uniform distribution and high acidity after NiCo impregnation. The highest activity is conferred by 10%Ni-10%Co/ACP at 93.8% and 90.2% of H2 yield and toluene conversion, respectively, with 325 h of stability. This is attributed to high turnover frequency, small crystallite size, weak metal-support interaction (WMSI) and simultaneous NiCo reducibility. The WMSI leads to carbon nanotube formation with tip-growth mechanism and suppresses catalyst deactivation. The reaction is endothermic and non-spontaneous with an ordered system at transition state. The results imply that the oxygenated functionalized ultramicroporous palm kernel shell-based ACP has a great potential as a high-performance catalyst in steam reforming of tar for H2 production.