Removal of Trace Contaminants from Fuel Processing Reformate: Preferential Oxidation (Prox)

Castaldi, Marco J.

doi:10.1002/9780470561256.ch7

Cited by 2 publications

(2 citation statements)

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“…In particular, producing clean energy from syngas and hydrogen feedstocks in fuel cells can simultaneously enhance the efficiency of energy production, supply clean fuels, and mitigate the emission of pollutants to the atmosphere. , However, residual contaminants from the autothermal reforming reactions (such as CO, CO 2 , and H 2 O), depending on the analyzed concentrations and operation conditions, can drastically reduce the performances of fuel cells. , Therefore, several methods have been investigated to remove these contaminants from fuel cell streams, such as adsorption including powder-activated carbon, (PAC), and pressure swing adsorption, (PSA), membrane separation, scrubbing, and preferential oxidation (PROX).…”

Section: Introductionmentioning

confidence: 99%

Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/M_xZr_yO_z Catalysts and Influence of CO₂ and H₂O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

Gaioto,

Pinto,

Schmal

2024

ACS Omega

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In the present paper, the effects of metal promoters (M = Fe, Co, and Cu) in Pt/ M x Zr y O z catalysts and the influence of CO 2 and H 2 O on the CO oxidation activity (PROX) were investigated. To do that, characterizations of catalyst structures and surfaces were performed and reported here. The catalyst Pt/Fe x Zr y O z (PFeZ) was the most active at low temperatures among the analyzed ones. The addition of platinum caused strong interaction with the mixed oxide, affecting the structure and the surface composition, blocking basic sites, and thus preventing catalyst deactivation. Particularly, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) results evidenced the formation of carboxylate and carbonate species. Besides, the addition of CO 2 and H 2 O in the gas feed stream affected the observed CO oxidation results, showing that CO 2 competes with O 2 on metallic sites. Moreover, DRIFTS and temperature-programmed desorption (TPD) analyses suggested the occurrence of OH − oxidation by CO, leading to the formation of highly reactive compounds that can be easily oxidized.

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Section: Introductionmentioning

confidence: 99%

Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/M_xZr_yO_z Catalysts and Influence of CO₂ and H₂O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

Gaioto,

Pinto,

Schmal

2024

ACS Omega

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“…As an inherent characteristic of CO-PROX, CO selectivity drops with temperature, and the steepness of the fall mainly depends on the difference between the CO and H 2 oxidation reaction onsets [17]. Interestingly, although there are comprehensive reports addressing the competitive nature between CO and H 2 oxidation reactions on CuO/CeO 2 , the underlying interaction of hydrogen with CO oxidation is still an unresolved question [11,[18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Investigations of the Effect of H2 in CO Oxidation over Ceria Catalysts

et al. 2021

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The preferential CO oxidation (so-called CO-PROX) is the selective CO oxidation amid H2-rich atmospheres, a process where ceria-based materials are consolidated catalysts. This article aims to disentangle the potential CO–H2 synergism under CO-PROX conditions on the low-index ceria surfaces (111), (110) and (100). Polycrystalline ceria, nanorods and ceria nanocubes were prepared to assess the physicochemical features of the targeted surfaces. Diffuse reflectance infrared Fourier-transformed spectroscopy (DRIFTS) shows that ceria surfaces are strongly carbonated even at room temperature by the effect of CO, with their depletion related to the CO oxidation onset. Conversely, formate species formed upon OH + CO interaction appear at temperatures around 60 °C and remain adsorbed regardless the reaction degree, indicating that these species do not take part in the CO oxidation. Density functional theory calculations (DFT) reveal that ceria facets exhibit high OH coverages all along the CO-PROX reaction, whilst CO is only chemisorbed on the (110) termination. A CO oxidation mechanism that explains the early formation of carbonates on ceria and the effect of the OH coverage in the overall catalytic cycle is proposed. In short, hydroxyl groups induce surface defects on ceria that increase the COx–catalyst interaction, revealed by the CO adsorption energies and the stabilization of intermediates and readsorbed products. In addition, high OH coverages are shown to facilitate the hydrogen transfer to form less stable HCOx products, which, in the case of the (110) and (100), is key to prevent surface poisoning. Altogether, this work sheds light on the yet unclear CO–H2 interactions on ceria surfaces during CO-PROX reaction, providing valuable insights to guide the design of more efficient reactors and catalysts for this process.

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Removal of Trace Contaminants from Fuel Processing Reformate: Preferential Oxidation (Prox)

Cited by 2 publications

References 44 publications

Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/M_xZr_yO_z Catalysts and Influence of CO₂ and H₂O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/M_xZr_yO_z Catalysts and Influence of CO₂ and H₂O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

Investigations of the Effect of H2 in CO Oxidation over Ceria Catalysts

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Removal of Trace Contaminants from Fuel Processing Reformate: Preferential Oxidation (Prox)

Cited by 2 publications

References 44 publications

Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/MxZryOz Catalysts and Influence of CO2 and H2O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/MxZryOz Catalysts and Influence of CO2 and H2O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

Investigations of the Effect of H2 in CO Oxidation over Ceria Catalysts

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Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/M_xZr_yO_z Catalysts and Influence of CO₂ and H₂O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction

Effects of Metal Promoters (M = Fe, Co, and Cu) in Pt/M_xZr_yO_z Catalysts and Influence of CO₂ and H₂O on the CO Oxidation Activity (PROX): Analysis of Surface Properties After Reaction