Ni(Co)-containing catalysts based on perovskite-like ferrites for steam reforming of ethanol

Abstract

Catal. Sustain. Energy 2014; Volume 2: 10-20 IntroductionCatalytic steam reforming (SR) is now considered as the main pathway to produce hydrogen and synthesis gas from alcohols and other oxygenates derived from fast pyrolysis of biomass as a renewable feedstock [1][2][3][4][5][6][7]. Biohydrogen and bio-syngas could be used for production of liquid fuels (gasoline, diesel) and valuable chemicals production, and they are the cleanest fuels for different types of fuel cells, gas turbine, internal combustion engine as well.The active catalysts for bio-ethanol steam reforming (ESR) are usually based on supported transition metals (Ni, Co) [8][9][10][11][12][13][14] or noble metals [15][16][17][18][19]. The major problem of ethanol SR hindering its industrial application, especially in the case of Ni-containing catalysts, is their coking leading to deactivation [8][9][10][11][12][13][14]. The use of perovskitelike oxides ABO 3 as catalyst precursors or supports is an attractive approach to minimize the coke deposition on catalysts. Thus, recently, in our study of methane dry reforming over LnFe 0.7-x Ru x Ni 0.3 O 3-d (Ln = La, Pr, Sm, x = 0 -0.1) perovskites [20][21], their transformation into composites comprised of Ni-Fe-(Ru) alloy particles and LnO x epitaxially bound with disordered Ln-Fe-O perovskite particles was demonstrated. This microstructure plays an important role in the high catalysts resistance to coking due to activation of CO 2 on the oxide sites and oxidation of CH x fragments at alloy particles/support interface by thus formed active oxygen-containing species. The nature of Ln cation affects both the composition of Ni-Fe-(Ru) alloy and oxygen mobility/reactivity in perovskite.In the case of oxygenates reforming, perovskites as the catalyst precursors were reported only in few works [22][23][24][25][26][27]. Thus, LaMO 3 (M= Ni, Co, Fe, Mn) perovskites have been studied in the authothermal reforming of ethanol [22]. Nickel-supported Ca(Sr)-substituted La 1-x Ca(Sr) x FeO 3 perovskite oxide catalysts have shown very good stability and activity in steam reforming of ethanol [24].Another option for improving Ni-catalysts stability to coking is addition of molybdenum. It has been suggested that molybdenum-containing catalysts could possess Abstract: For two series of catalysts based on praseodymium ferrite, their structural and redox properties as well as performance in ethanol steam reforming have been studied. The first series was PrFe 1-x Ni(Co) x O 3 (x=0.3-0.4) perovskites prepared by modified Pechini route, and the second one was 5%wt.Ni(Co)/PrFeO 3 of different dispersion prepared by impregnation of PrFeO 3 , including samples modified by 5%wt. Mo. At temperatures above 700°C, for all catalysts, the main products were hydrogen and CO. At temperatures below 700°C, initial ethanol conversion and hydrogen yield were higher for supported catalysts as compared with ones derived from Ni(Co)-containing perovskites. While Ni-based catalysts derived from perovskite were more active as compared with Co-ba...

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