Hydrogen Production from Ethanol over Rh–Pd/CeO2 Catalysts

Abstract

The work presents a study by temperature programmed desorption, in situ infra red spectroscopy and catalytic steam reforming of ethanol (SRE) over CeO 2 and the bimetallic Pd-Rh/CeO 2 ; comparison with the monometallic catalysts (Rh/CeO 2 and Pd/CeO 2 ) was also made for the steam reforming study. Comparing TPD of ethanol over CeO 2 and the bimetallic catalysts indicated two main differences: the direct oxidation route to acetate over CeO 2 is suppressed by the presence of the metal and the lowering of the dehydrogenation reaction temperature by about 100 K. In situ IR study indicated that the bimetallic catalyst breaks the carbon-carbon bond of ethanol at low temperature \400 K, as evidenced by the presence of adsorbed CO species. SRE over wt.% Rh-wt.% Pd/ CeO 2 , at 770 K at realistic conditions showed that maximum conversion and selectivity could be achieved. This high activity considering the very small amounts of transition metals on CeO 2 is discussed in light of their electronic and geometric effects.

Monometallic Carbonyl‐Derived CeO2‐Supported Rh and Co Bicomponent Catalysts for CO‐Free, High‐Yield H2 Generation from Low‐Temperature Ethanol Steam Reforming

“…The Ar/(C 2 H 5 OH+H 2 O) molar ratio and the gas phase hourly space velocity (GHSV) amounted to approximately 7 and 26 500 h (i.e.,17 800 mL g −1 h −1 ), respectively, which were assessed to be conditions favorable for C 2 H 5 OH conversion, H 2 production and CO removal in ESR referring to reported work 25. 94, 95 The ESR reaction was consecutively run from 250 to 600 °C and each reaction temperature was held for 30 min. The reaction products were analyzed twice on‐line by gas chromatography after 10 min of reaction at each reaction temperature.…”

“…Of the supported bicomponent metal catalysts reported to date, those containing Rh predominate 21. 32, 34, 36, 38, 42, 48, 50–53, 64 However, only a limited few relate to supported Rh and Co bicomponent catalysts 38. 48, 51–53, 64 Pereira et al.…”

The influence of nano-architectured CeO supports in RhPd/CeO2 for the catalytic ethanol steam reforming reaction

“…In contrast, noble metals, and in particular Rh and Ru, are known to successfully break the C C bond leading to less coke deposition and thus results in more stable catalysts. As first reported by the Idriss' group, the bimetallic Rh Pd system supported over CeO 2 has shown excellent catalytic performance for ESR, with a delicate interaction between the bimetallic nanoparticles and the oxide support [6]. The cooperative effect of C C bond cleavage provided by Rh together with hydrogen recombination favored by Pd and the simultaneous dissociation of H 2 O and oxygen mobility provided by CeO 2 results in a highly active, selective and stable multifunctional catalyst for ESR [7].…”

Structure and reactivity of Au–Rh bimetallic clusters on titanate nanowires, nanotubes and TiO2(110)

“…Catalytic conversion of bio-ethanol received considerable attention in the last decade [32][33][34][35][36][37] and the search for the most active, stable and selective catalyst has resulted in many heterogeneous catalytic systems.…”