High selectivity to hydrogen on the methane decomposition over Rh/γ-Al2O3-Nd2O3 catalysts

Methane decomposition was carried out on Rh/gamma-Al2O3 and Rh/gamma-Al2O3 Nd2O3 catalysts to produce hydrogen. gamma-Al2O3 Nd2O3 mixed oxides and Rh/gamma-Al2O3 Nd2O3 catalysts were prepared by wet impregnation using Nd(NO3)(3).6H(2)O and RhC13.3H(2)O as precursors. The concentrations for the catalysts were 1.0 wt% for Rh and 1 and 10 wt% for Nd. The reaction was carried out from 400 to 750 degrees C. All catalysts showed high activity and selectivity at 700 degrees C, with conversions around 74-79 vol%. The activity per site (TOF) was higher on Rh crystallites size >= 2.1 nm. The Rh catalyst with 10 wt% neodymium concentration was highly selective to hydrogen, 100%. This behavior was explained by the highest interaction between Rh and gamma-Al2O3 Nd203 supports. Rh/gamma-Al2O3 and Rh/gamma-Al2O3 Nd2O3 with 1 wt% Nd showed selectivities of 89 and 65% at 700 degrees C respectively and ethane and ethylene products. These products come from the mobility of CHx species on the Rh surface during the reaction. The carbon produced was mainly deposited on the support. Characterization was done by XRD, N-2 adsorption isotherms, HRTEM, EDS-SEM, CO-FTIR, H-2-TPR, XPS. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.