Study of ethanol dehydrogenation reaction mechanism for hydrogen production on combustion synthesized cobalt catalyst

•Thermodynamic equilibrium analysis was performed on combustion synthesis for cobalt catalyst production.•Comparative effect of reducing agents (glycine, urea, hydrazine, citric acid) on combustion synthesis was studied.•Ethanol adsorbs on the surface and decomposes to release hydrogen following ethoxy intermediate formation.•Ethanol decomposition at higher temperature leads to carbon formation.

Cobalt nanoparticles synthesized via solution combustion synthesis were used to study the decomposition mechanism of ethanol for hydrogen production. Thermodynamic studies were conducted on the synthesis of cobalt nanoparticles using cobalt nitrate as a metal precursor in presence of different reducing agents; hydrazine, glycine, urea and citric acid. Thermodynamic results along with experimental characterizations show that the type and amount of fuel influence the adiabatic combustion temperature and the gases released during synthesis process affecting nanoparticle size, porosity and microstructure. The synthesized nanoparticles were activated by passing H2 at 300 °C inside the reaction chamber before being used for studying the reaction pathway of catalytic dehydrogenation of ethanol. These studies indicate that cobalt catalyst is selective for aldehyde and acetate species along with the formation of H2, H2O and CO2. Production of methane was also observed on cobalt surface at 400 °C. The spent catalyst nanoparticles were characterized after the reaction using XRD, SEM and TEM to analyze the particle size and its morphology. Results indicate a growth in particle size due to sintering, and carbon formation on the catalyst surface due to coking during ethanol dehydrogenation reaction.