Hierarchically carbonaceous catalyst with Brønsted–Lewis acid sites prepared through Pickering HIPEs templating for biomass energy conversation

Abstract

In this study, macroporous inorganic–organic hybrid polymers (MIPs) were prepared using versatile high internal phase emulsions (HIPEs) templating to synthesize a novel catalyst for cellulose conversion. Upon the incomplete hydrothermal carbonization of MIPs and sulfonation with H2SO4, macroporous carbonaceous solid catalysts (MCSC) with hierarchical structures and Brønsted–Lewis acid sites were obtained. The synthesized MCSC was found to be highly effective to produce 5-hydroxymethylfurfural (HMF) in the 1-butyl-3-methyl-imidazolium chloride ([BMIM]-Cl) ionic liquids. It was shown that remarkable HMF yield (43.1%) and selectivity (57.7%) can be obtained and the catalyst is recyclable up to four consecutive cycles without significant loss of catalytic activity. This implies that catalysts with designed physicochemical characteristics are advantageous over traditional ones in producing HMF. A catalytic scheme was proposed to characterize the cellulose conversion to HMF using the MCSC.