Pt supported on modified-coal gasification slag for efficient dehydrogenation of methylcyclohexane in a fixed bed reactor

Coal gasification slag (CGS) was used for modification and loaded platinum (Pt) to liquid organic hydrogen carrier (LOHC) for the first time. The carbon hybrid silica (C/SiO₂) was prepared by removing metal oxides and carbon residue of CGS through acid treatment and calcination. The C/SiO₂ loaded Pt (Pt-C/SiO₂) exhibited only a 1.3% decrease in dehydrogenation conversion rate after 30 h of continuous catalytic dehydrogenation of methylcyclohexane (MCH), and even after 100 h, the decrease was only 4.9%. When Pt was directly loaded on CGS (Pt-CGS), it showed higher catalytic activity (dehydrogenation conversion rate was 20.4%), but lower catalytic stability (dehydrogenation conversion rate decreased by 56% after 7 h). Additionally, commercial Pt-SiO₂ catalysts exhibited poor dehydrogenation conversion rate, significantly lower than that of Pt-C/SiO₂. Density functional theory calculations confirmed the influence of carbon hybrid SiO₂ on the adsorption energy, electron transfer and density of states for the catalytic dehydrogenation of MCH. The highly active and stable Pt-C/SiO₂ catalyst can be effectively utilized for LOCH while achieving high-value utilization of CGS solid waste.