Effects of carbon support on microwave-assisted catalytic dehydrogenation of decalin

Abstract

Five types of carbon materials, including carbon nanotubes (CNTs), carbon nanofibres, carbon black, activated carbon and graphite, were evaluated in searching for an appropriate support for a Pt catalyst used for the dehydrogenation of decalin under microwave irradiation (MW). The thermal behaviour of different carbon materials and supported Pt catalysts suspended in decalin under MW was investigated. The dielectric properties and electrical conductivities of the carbon- and catalyst-containing decalin suspensions were measured and correlated with the thermal behaviour of the corresponding samples. Structural and textural characterisation was carried out to interpret the differences between the electrical conductivity of different samples. The catalytic performance of the Pt catalysts supported on different carbon materials was assessed to determine the catalysts’ ability to release H2 during decalin dehydrogenation under MW. The results show that CNTs are the most suitable catalyst support because they exhibit the best thermal behaviour under MW and can provide a relatively large surface area for dispersing Pt nanoparticles. The high aspect ratio and low bulk density of CNTs gives rise to high electrical conductivity and, consequently, the large dielectric loss displayed by CNT-containing suspension, causing the outstanding thermal behaviour of CNT-containing suspension under MW.