Activated carbon incorporated with first-row transition metals as catalysts in hydrogen production from propane

Transition metals (V, Mn, Fe, Co and Ni) were mixed with bituminous coal and carbonized at 600 °C to obtain activated carbons (AC) with different catalytic and physical properties. A variety of analytical techniques – XRD, SEM, FTIR and BET surface area – were used to characterize the samples. The presence of different proportions of crystalline structures and surface functional groups were observed depending on the metal added in the carbon matrix. The samples surface areas changed from 140.9 to 296.0 m2/g for V- and Ni-AC, with corresponding increase in pore volumes and diameters. There are graphitic and metal-carbon phases as evidenced by XRD. The aromatic stacking appears to decrease from V- to Co-AC. V-AC exhibited fewer occurrences of turbostratic carbon interlayers. In the FTIR spectra, region assigned to aromatic CC stretching and CH-bending have been observed. Their relative proportions diminish based on the nature of the transition metal used. The samples were tested as catalysts at 450–550 °C using a feed mixture of propane and argon – in the presence or absence of CO2 in the feed stream. Propylene selectivities per unit area increase along the groups of the metals. Ni-AC exhibited the best performance per gram in terms of propane conversions (1.5–17.7%) and selectivities to propylene (39.9–49.0%) in the temperature range. Partial substitution of argon with CO2 in the feed exhibited general increase in propane conversion with no significant change in propylene selectivities.