Catalytic ability of MgO to break C[sbnd]H bonds during slurry oil carbon deposition

Abstract

Although MgO has been widely used for the MgO-templated synthesis of carbon materials, little attention has been paid to MgO’s catalytic function during carbon deposition. Here, a systematic analysis of the products of slurry oil (SO) carbonization with and without MgO templates present indicates that MgO catalytically promoted the breakage of CH bonds by immobilizing heavy oil molecules on MgO surfaces and the attractive interaction between hydrogen and MgO. Compared with the carbonization of SO alone, a notably higher H2 concentration and a lower hydrocarbon concentration was observed in the tail gas, a higher solid yield and a lower degree of graphitization of the carbon product were observed when MgO was also present. Furthermore, treatment at 900°C in the presence of MgO efficiently enhanced the capacitance and rate capability of the as-obtained porous carbon when tested as an electrode material for supercapacitors. These results suggest that the catalytic function of MgO could exist in all MgO-templated syntheses and in the heat treatment of porous carbons and graphene.