Aqueous phase reforming of ethylene glycol over bimetallic platinum-cobalt on ceria–zirconia mixed oxide

Abstract

The roles of cobalt promoter on the bimetallic platinum-cobalt supported on the CeO2-ZrO2 mixed oxide were investigated for aqueous phase reforming reaction of ethylene glycol (EG) to verify the effects of cobalt to an enhanced activity and stability of PtCo/CeO2-ZrO2, where the CeO2-ZrO2 mixed oxide was prepared by sol–gel method at a fixed Ce/(Ce + Zr) molar ratio of 0.4. The enhanced catalytic activity for an aqueous-phase reforming (APR) as well as water gas shift (WGS) reaction of EG was observed on the PtCo/CeO2-ZrO2 at a Co/Pt molar ratio of 0.5. The higher activity and stability on the PtCo/CeO2-ZrO2 at an optimal Co/Pt ratio were mainly attributed to an enhanced WGS activity and less aggregation of active metals due to a high dispersion of platinum nanoparticles with a proper interaction between platinum and oxophilic cobalt nanoparticles. A facile reduction behavior of the supported bimetallic platinum-cobalt nanoparticles through an enhanced hydrogen spillover on the platinum nanoparticles also increased CC cleavage reaction of EG with the suppressed deposition of inactive coke precursors on the partially reduced active nanoparticles. These synergy effects of platinum-cobalt nanoparticles with a close interaction and a less aggregation of active metals were responsible for an enhanced APR and WGS activity on the PtCo/CeO2-ZrO2 at an optimal Ce/(Ce + Zr) ratio as well.