Efficient hydrogen production by methanol aqueous phase reforming over KMnO4 modified PtMnK/AC catalyst: Regulating the hydrophilicity of carbon support

Abstract

The production of hydrogen through the aqueous phase reforming of biomass-derived oxygenates has broad application prospects in distributed hydrogen energy systems. Activated carbon is commonly employed as a catalyst support in catalytic aqueous phase reforming due to its high surface area and hydrothermal stability. Nevertheless, its hydrophobicity hinders the efficient adsorption of water molecules, which affects the activity of the aqueous phase reforming reaction. In this study, catalysts using carbon as support with varying hydrophilicity were synthesized using nitric acid and potassium permanganate as modifiers. The efficiency of these catalysts was then examined in the aqueous phase reforming reaction of methanol and the water gas shift reaction, respectively. The impact of the hydrophilicity of the support on the reaction performances was examined with diverse characterization techniques. The results demonstrated that the PtMnK/AC catalyst exhibited 1.2 times the hydrogen production yield compared to the conventional Pt/AC catalyst, indicating that enhancing the hydrophilicity of the support promoted the water gas shift reaction while limiting methanation side reactions in methanol aqueous phase reforming. The effective interaction between hydrophilic surfaces and oxygen vacancies enhances the catalyst's capability to dissociate H2O and react with CO* intermediates to generate more hydrogen, which is regarded as the rate determining step of methanol aqueous phase reforming.