Hydrogen production by ethanol steam reforming over Rh nanoparticles supported on lanthana/silica systems

LEANDRO CORONEL, JOHN F. MÚNERA, ANA M. TARDITI, M.S. MORENO Y LAURA M. CORNAGLIA

APPLIED CATALYSIS B-ENVIRONMENTAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 160 p. 254 - 266

0926-3373

tThe aim of the present work was to investigate Rh nanoparticle catalysts supported on La2O3?SiO2,with different contents of La2O3, in the ethanol steam reforming reaction. The size of Rh particles wasdetermined by both XPS, applying the Davis model, and CO chemisorption measurements. Particle sizesbetween 1.2 and 3 nm were estimated with these techniques. The catalyst with 15 wt.% of La2O3was themost stable one under the different reaction conditions under study, i.e. 773 K and water to ethanol molarratios of 3 and 5. In order to explain the deactivation observed in the other catalysts, the samples used inthe reaction were characterized by XPS, TEM and in situ Raman spectroscopy. The TEM results alloweda direct visualization of the carbon deposits that presented different degrees of catalyst coverage. Thesurface of the most stable catalyst was not fully covered by carbon while the Rh/La2O3(40)?SiO2sample,which deactivated partially, exhibited a carbon layer uniformly distributed over the surface. The oxidationof the carbon deposits was analyzed using in situ Raman spectroscopy. Results were in agreement withthose obtained by TEM microscopy. DRIFTS experiments under reaction conditions suggested that thedirect decomposition of ethoxy species would produce hydrogen, CO, and CHxspecies, which could resultin carbon formation.