Activated carbon from Bulgarian peach stones as a support of catalysts for methanol decomposition

Abstract

This study is aimed at the development of intelligent integrated scheme for full utilization of biomass for clean energy production. The proposed approach includes production of activated carbon based catalysts for methanol decomposition as a source of hydrogen, where both activated carbon and methanol, could be produced from biomass. In order to elucidate the impact of different activated carbon characteristics on the formation of the catalytic active phase, carbons with different texture and surface functionality are purposely obtained by changes in the activation temperature during the carbon preparation and its post-synthetic treatment with nitric acid. Peach stones, widely available in Bulgaria and Balkans region, are chosen as activated carbons precursor. Iron, zinc and ferrite modifications of thus obtained carbons are prepared by incipient wetness impregnation technique and nitrogen physisorption, XRD, HRTEM, UV-Vis, FTIR, Moessbauer spectroscopy, TPR with hydrogen and Boehm method are used for samples characterization. It is established that the state and catalytic activity of the supported metal oxide particles could be easily controlled by the procedure of the activated carbon preparation and this effect strongly depends on the nature of the loaded metal oxide. In case of iron modifications, the increase of the activation temperature during the carbon preparation promotes the formation of more finely dispersed, accessible for the reactants and active in methanol decomposition magnetite particles. The dispersion and the accessibility of the zinc oxide species in zinc modifications are improved by the formation of additional amount of surface acidic groups during the carbon pre-treatment with nitric acid. The combination of lower temperature of carbon activation with nitric acid pre-treatment promotes the formation of highly active ferrite nanoparticles in the binary modifications.