Promotional role of MgO on sorption-enhanced steam reforming of ethanol over Ni/CaO catalysts

This article describes the design and synthesis of MgO-modified Ni/CaO catalysts for sorption-enhanced steam reforming of ethanol. The results show that the introduction of MgO effectively increases the dispersion of CaO via forming MgCa(CO 3 ) 2 precursor. In the prepared MgO-modified Ni/CaO catalysts, metallic Ni exists around MgO supported on CaO. Both 100% ethanol conversion and >96% hydrogen purity can be stabilized in 10 cycles over the catalyst containing 20 wt% MgO. The interaction between metallic Ni and MgO enhances the sintering resistance of the catalyst. More importantly, reaction pathway studies have confirmed that the formation of CaCO 3 hinders the activation of H 2 O on the Ni/CaO catalyst surface, and thus inhibits the conversion of the reaction intermediates including HCO* and CH x *. MgO can dissociate H 2 O to form hydroxyl groups which participate in the conversion of the reaction intermediates, thereby the MgO-modified Ni/CaO catalysts have better catalytic performance and carbon deposition resistance.