Effect of Ni Metal Content on Emulsifying Properties of Ni/CNTox Catalysts for Catalytic Conversion of Furfural in Pickering Emulsions

Abstract

Ni/CNTox catalysts with variable metal content have been prepared to investigate their emulsifying and catalytic properties for the liquid?phase conversion of furfural. The solid catalysts and emulsions were analyzed by several characterization techniques. The catalytic activity linearly increased with increasing Ni content (up to 10 wt.%) before dropping down again for a Ni content of 15 wt.%. The loss of catalytic activity was attributed to larger emulsion droplets formed by the inhibition of hydrophilic sites. All Ni/CNTox catalysts were highly selective to cyclopentanone as a main product, while several changes regarding secondary product were observed. Ni/CNTox catalysts with a Ni content up to 10 wt.% favor the formation of levulinic acid, while catalysts with a Ni content of 15 wt.% were selective to tetrahydrofurfuryl alcohol. This was attributed to an inhibition of the acid sites thus favoring the catalyst’s hydrogenating capacity.