The formation of a hydrothermal carbon coating on graphite microfiber felts for using as structured acid catalyst

Abstract

A hydrothermal carbon layer has been coated on graphite felt using a carbohydrate solution (glucose, sucrose or starch) as precursor. The coating is uniform in thickness and coverage, and exhibits excellent adhesion to the substrate. It is highly hydrophilic, very accessible to reactants and the thickness can be tuned by the synthesis conditions. The coating was functionalized with sulfonic acid groups and its morphology and surface chemistry characterized by SEM, TPO-MS, IR-spectroscopy and XPS. The sulfonated material has been tested in the esterification of palmitic acid with methanol exhibiting significant activity and stability.

Biobased catalyst in biorefinery processes: sulphonated hydrothermal carbon for glycerol esterification

“…27 Carbons prepared under mild conditions, such as hydrothermal carbon (HTC), are very attractive materials from a sustainability point of view. Sulphonated hydrothermal carbon (SHTC) has been used as a solid acid catalyst in esterification reactions of fatty acids, [28][29][30][31] showing remarkable performance despite the apparently very low surface area. In this manuscript, we present a deep study of the acetylation of glycerol catalysed by sulphonated hydrothermal carbon (SHTC).…”

Deactivation of sulfonated hydrothermal carbons in the presence of alcohols: Evidences for sulfonic esters formation

“…Furthermore, hydrothermal carbon synthesis is a very versatile method to prepare materials with different porous structures [20][21][22][23][24] and shapes, such as hollow capsules [25][26][27], nanowires [28] or nanotubes [29]. Recently, it has been demonstrated by our group that HT carbon films can be also coated on a structured macroscopic support such as graphite felt [30].…”

Chapter 3. Novel carbon materials modified with heteroatoms as metal-free catalyst and metal catalyst support

“…Sulfonated hydrothermal carbon in the form of microspheres or as coating of graphite microfibers has been tested in esterification of palmitic acid with ethanol. 147,148 The catalyst exhibited high activity but some deactivation occurred after reuse due mainly to the blocking of sulphonated sites by chemical reaction with methanol. 147 Nevertheless, hydrothermal carbon is a versatile carbon material because it has high oxygen content making it amenable to heteroatom funcitionalization, it is prepared in a sustainable manner and it can be moulded in different nano and macroshapes (Fig.…”

“…14). 148,149 These properties render hydrothermal carbon a good candidate for heteroatom doping and subsequent use for various catalytic applications. 150,151 Concerning water treatment application, activated carbons treated with sulphuric acid showed an unexpected efficiency in catalytic wet peroxide oxidation of a model anionic azo dye, 152 since this type of reactions is generally favoured by basic carbons.…”