Catalysts for H 2 production using the ethanol steam reforming (a review)

Contreras, J. L.; Salmones, J.; Colín-Luna, J.A.; Nuño, L.; Quintana, B.; Córdova, I.; Zeifert, Beatriz; Tapia, Carlos; Fuentes, Gustavo A.

doi:10.1016/j.ijhydene.2014.08.072

Cited by 231 publications

(140 citation statements)

References 111 publications

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“…Formation of the oxygen vacancies leads to generation of additional electron states in the gap region. In the m-ZrO 2 bulk, the states are formed at approximately 0.5 and 0.2 eV below the edge of the conductive band for the 4 O B and 3 O B vacancies, respectively, showing the same trend as has been reported. [40] In the case of the surfaces, the position of the defect states seems to correlate with the location of the vacancy in the lattice.…”

Section: Formation Of Single Oxygen Vacanciessupporting

confidence: 80%

“…Due to its unique properties, zirconia acts as a heterogeneous support and a catalyst component in multiple important processes for obtaining sustainable chemicals, as has been highlighted in the recent reviews and reports. [17,21,4,26,25,11,37] Moreover, zirconia finds its applications in, for instance, solid oxide fuel cells [32] and electrochemical sensors. [22] Zirconia exists in several polymorphic modifications, among which monoclinic (m), tetragonal (t), and cubic (c) are the most common examples.…”

Section: Introductionmentioning

confidence: 99%

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Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Bazhenov

Honkala

2016

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Under the water-rich pre-treatment and/or reaction conditions, structure and chemistry of the monoclinic zirconia surfaces are strongly influenced by oxygen vacancies and incorporated water. Here, we report a combined first-principles and atomistic thermodynamics study on the structure and stability of selected surfaces of the monoclinic zirconia. Our results indicate that among the studied surfaces, the most stable (111) surface is the least vulnerable towards oxygen vacancies in contrast to the less stable (011) and (101) surfaces, where formation of oxygen vacancies is energetically more favorable. Furthermore, we present a vigorous, systematic screening of water incorporation onto the studied surfaces. We observe that the greatest stabilization of the surfaces is achieved when a part of the adsorbed water molecules is dissociated. Nevertheless, the importance of water dissociation for achieving the greatest stabilization is high for the less stable (011) and (101) surfaces, while completely hydrated (111) surface is stabilized equally regardless of the water dissociation state. Analysis of the constructed phase diagrams reveals that the (111) surface remains preferably clean and the (011) and (101) surfaces have dissociated water at low coverage under the reactive conditions of T = 600-900 K and p(H 2 O) < 1 bar. Upon temperature decrease and/or pressure increase, all studied surfaces gradually uptake water until fully hydrated. All in all, our findings complement and broaden the existing picture of the structure and stability of the monoclinic zirconia surfaces under the pre-treatment and/or reaction conditions, enabling rationalization of the potential roles of zirconia as a heterogeneous support and a catalyst component.

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Section: Formation Of Single Oxygen Vacanciessupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Bazhenov

Honkala

2016

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“…(1), the complete reaction scheme is far more complex, obtaining not only H 2 and CO 2 , but also CO, CH 4 , and, in some cases, acetaldehyde and ethylene [4]. As a consequence, in addition to high activity to attain the greatest conversion possible, high hydrogen selectivity is needed to avoid the formation of undesirable sub products which may result in carbon formation [5,6].…”

Section: Bioethanol Steam Reformingmentioning

confidence: 99%

Hydrogen Production from Bioethanol: Behavior of a Carbon Oxide Preferential Oxidation Catalyst

et al. 2017

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Hydrogen is recognized as a promising green energy source, particularly when used to feed a polymer electrolyte membrane fuel cell (PEMFC). Here, hydrogen was obtained by bioethanol steam reforming with CO and CO 2 as primary sub products. Since the cell anode is extremely sensitive to poisoning with CO, watergas shift (WGS) and carbon oxide preferential oxidation (COPROX) reactors were employed for hydrogen purification. Catalysts prepared by our lab were tested at pilot plant scale in both the reformer and COPROX unit, where different active phase distributions, stoichiometric excess of air, and reaction temperatures were tested. The use of two different COPROX units with intermediate air injection was also considered. The as-prepared catalysts showed good stability and performance.

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“…However, Ni promotes the formation of carbonaceous species, and it has low stability [23]. In contrast, noble metals are promising candidates for SRE because of their higher activity and stability with a low formation of coke [24]. Among the noble metals, Rh catalysts showed better performance in terms of conversion of ethanol and H 2 production [25], even at low catalyst loadings (<1 wt %) [26].…”

Section: Introductionmentioning

confidence: 99%

Response Surface Methodology and Aspen Plus Integration for the Simulation of the Catalytic Steam Reforming of Ethanol

2017

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Abstract:The steam reforming of ethanol (SRE) on a bimetallic RhPt/CeO 2 catalyst was evaluated by the integration of Response Surface Methodology (RSM) and Aspen Plus (version 9.0, Aspen Tech, Burlington, MA, USA, 2016). First, the effect of the Rh-Pt weight ratio (1:0, 3:1, 1:1, 1:3, and 0:1) on the performance of SRE on RhPt/CeO 2 was assessed between 400 to 700 • C with a stoichiometric steam/ethanol molar ratio of 3. RSM enabled modeling of the system and identification of a maximum of 4.2 mol H 2 /mol EtOH (700 • C) with the Rh 0.4 Pt 0.4 /CeO 2 catalyst. The mathematical models were integrated into Aspen Plus through Excel in order to simulate a process involving SRE, H 2 purification, and electricity production in a fuel cell (FC). An energy sensitivity analysis of the process was performed in Aspen Plus, and the information obtained was used to generate new response surfaces. The response surfaces demonstrated that an increase in H 2 production requires more energy consumption in the steam reforming of ethanol. However, increasing H 2 production rebounds in more energy production in the fuel cell, which increases the overall efficiency of the system. The minimum H 2 yield needed to make the system energetically sustainable was identified as 1.2 mol H 2 /mol EtOH. According to the results of the integration of RSM models into Aspen Plus, the system using Rh 0.4 Pt 0.4 /CeO 2 can produce a maximum net energy of 742 kJ/mol H 2 , of which 40% could be converted into electricity in the FC (297 kJ/mol H 2 produced). The remaining energy can be recovered as heat.

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Catalysts for H 2 production using the ethanol steam reforming (a review)

Cited by 231 publications

References 111 publications

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Hydrogen Production from Bioethanol: Behavior of a Carbon Oxide Preferential Oxidation Catalyst

Response Surface Methodology and Aspen Plus Integration for the Simulation of the Catalytic Steam Reforming of Ethanol

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