The formation of active phases in Pt-containing catalysts for bicyclohexyl dehydrogenation in hydrogen storage.

The fundamental role of the carbon carrier Sibunit® in the formation of active and selective phases in low-percentage Pt-containing catalysts Pt/C, Pt/Ni/C, Pt/Ni-Cr/C for the complete dehydrogenation of bicyclohexyl into biphenyl (320 °C, 1 atm) is shown. The Pt/Ni-Cr/C catalyst showed the greatest activity and selectivity in the complete dehydrogenation of bicyclohexyl into biphenyl. Detailed analysis of the catalyst surface by XPS, TEM-HR and EDX methods revealed two main processes associated with the high activity and successful course of the reaction of bicyclohexyl dehydrogenation: the formation of an active carbide PtC phase and graphitization of the carbon carrier.

Activity of Mono-, Bi-, and Trimetallic Catalysts Pt-Ni-Cr/C in the Bicyclohexyl Dehydrogenation Reaction.

The influence of metals with different redox properties and a carbon carrier on the activity of mono-, bi- and trimetallic Pt-Ni-Cr/C catalysts has been studied in the bicyclohexyl dehydrogenation reaction as the hydrogen release stage in hydrogen storage. An increase in the conversion (X > 62%) of bicyclohexyl and selectivity for biphenyl (S > 84%) was observed on trimetallic catalysts Pt-Ni-Cr/C compared with the monometallic catalyst Rt/C (X > 55%; S > 68%). It has been established that the increase in the conversion of bicyclohexyl and selectivity for biphenyl in the dehydrogenation reaction on trimetallic catalysts is due to an increase in the activity of Pt nanoparticles in the vicinity of local Cr-Ni clusters of solid substitution solutions.

Kinetic Modeling of Hydrogen Production by Dehydrogenation of Polycyclic Naphthenes with Varying Degrees of Condensation.

The kinetics of reactions of dehydrogenation of polycyclic naphthenes (cyclohexane, decalin, bicyclohexyl, -, -, and -isomers of perhydroterphenyl) is modeled on the basis of a formal comparison of kinetic equations of the 1st and 2nd orders based on real experimental data. It is shown that the reaction of the 1st order is predominating in the series of cyclohexane-bicyclohexyl-perhydroparatherphenyl. For all other substrates, the probability of describing the reaction in accordance with the equation of the 2nd order increases markedly, and for trans-decalin it becomes the predominant form of describing the kinetics of the reaction.