Use of CuNi/YSZ and CuNi/SDC Catalysts for the Reverse Water Gas Shift Reaction

Lortie, Maxime; Isaifan, Rima J.

doi:10.1155/2015/601709

Cited by 6 publications

(5 citation statements)

References 31 publications

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“…Copper–nickel (CuNi) alloys have been successfully employed as catalysts in a number of reactions, including carbon dioxide and carbon monoxide hydrogenation, − hydrogenolysis of ethane and propane, , the reverse water–gas-shift reaction, ethanol steam reforming, , and methane decomposition, exhibiting increased catalytic activity compared to their monometallic counterparts. Doping of Cu surfaces with Ni has been theoretically shown to strongly promote methanol synthesis. − The addition of CO into the CO 2 hydrogenation reaction mixture further promotes methanol synthesis, an observation which was partly attributed to CO-induced surface segregation of Ni .…”

Section: Introductionmentioning

confidence: 99%

Segregation Phenomena in Size-Selected Bimetallic CuNi Nanoparticle Catalysts

et al. 2017

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Surface segregation, restructuring, and sintering phenomena in size-selected copper-nickel nanoparticles (NPs) supported on silicon dioxide substrates were systematically investigated as a function of temperature, chemical state, and reactive gas environment. Using near-ambient pressure (NAP-XPS) and ultrahigh vacuum X-ray photoelectron spectroscopy (XPS), we showed that nickel tends to segregate to the surface of the NPs at elevated temperatures in oxygen- or hydrogen-containing atmospheres. It was found that the NP pretreatment, gaseous environment, and oxide formation free energy are the main driving forces of the restructuring and segregation trends observed, overshadowing the role of the surface free energy. The depth profile of the elemental composition of the particles was determined under operando CO hydrogenation conditions by varying the energy of the X-ray beam. The temperature dependence of the chemical state of the two metals was systematically studied, revealing the high stability of nickel oxides on the NPs and the important role of high valence oxidation states in the segregation behavior. Atomic force microscopy (AFM) studies revealed a remarkable stability of the NPs against sintering at temperatures as high as 700 °C. The results provide new insights into the complex interplay of the various factors which affect alloy formation and segregation phenomena in bimetallic NP systems, often in ways different from those previously known for their bulk counterparts. This leads to new routes for tuning the surface composition of nanocatalysts, for example, through plasma and annealing pretreatments.

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Section: Introductionmentioning

confidence: 99%

Segregation Phenomena in Size-Selected Bimetallic CuNi Nanoparticle Catalysts

et al. 2017

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“…, one may conclude that possibly Ni/GDC has a higher (R)WGS-activity compared to Ni/YSZ, enabling similar (R)WGS rates despite the smaller electrode volume. This seems reasonable as ceria oxides have a higher catalytic RWGS activity compared to YSZ, 52 metallic catalysts supported on doped ceria show a higher RWGS activity than those supported on YSZ 53 and the addition of ceria to Al 2 O 3 supported Ni catalysts increases their WGS-activity. 54 However, changes in the linear regime are much harder to interpret and a very clear boundary for the onset of the electrochemical CO/CO 2 -conversion cannot be easily identified from Fig.…”

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confidence: 87%

Electrochemical Characterization of Nickel/Gadolinia Doped Ceria Fuel Electrodes under H₂/H₂O/CO/CO₂-Atmospheres

Esau,

Grosselindemann,

Sckuhr

et al. 2024

J. Electrochem. Soc.

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Modelling of the co-electrolysis process requires understanding of the underlying reaction pathways under H2/H2O/CO/CO2-atmospheres. These include the electrochemical steam reduction/hydrogen oxidation, the electrochemical CO2 reduction/CO oxidation and their coupling via the catalytic (reverse) water gas shift reaction ((R)WGS). The assumption of a very fast RWGS and therefore neglectable electrochemical CO2 conversion is commonly used to model the co-electrolysis process. In contrast, previous studies on Ni/GDC fuel electrodes suggest that the electrochemical conversion of CO / CO2 can be present in H2/H2O/CO/CO2-atmospheres. To deconvolute surface-related and non-surface-related processes in the impedance response we present results from a complex variation of operating parameters for process identification by the use of electrochemical impedance spectroscopy and the subsequent impedance analysis by the distribution of relaxation times. A physically meaningful equivalent circuit model, based on a single channel transmission line, is then derived. The model enables quantification of the surface reaction resistance under varied C/H-ratios. From a kinetic analysis it is shown that the electrochemical H2/H2O conversion is dominant for y_CO+y_(CO_2 )≤ 50% and electrochemical CO/CO2-conversion onsets from y_CO+y_(CO_2 )≥ 60%.

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“…As shown in Fig. 8, noble metals (Pt [74][75][76][77][78][79][80][81] , Ru 82,83 , Au 84,85 and Rh 86 ), Fe-based 82,[87][88][89][90] , Ni-based [91][92][93][94][95][96] , Cu-based 83,[97][98][99] and Co-based [100][101][102] are the most popular catalysts. It can be clearly observed that RWGS is favored at a higher reaction temperature.…”

Section: Catalysts In Dfms For Iccu-rwgsmentioning

confidence: 99%