Water-gas shift: an examination of Pt promoted MgO and tetragonal and monoclinic ZrO2 by in situ drifts

Chenu, Emilie; Jacobs, Gary; Crawford, Adam C.; Keogh, Robert A.; Patterson, Patricia M.; Sparks, Dennis E.; Davis, Burtron H.

doi:10.1016/j.apcatb.2004.12.013

Cited by 96 publications

(42 citation statements)

References 40 publications

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“…Thus, TPR is only used in a qualitative manner. The reduction of zirconia support exhibits two different peaks, respectively at ∼450 • C and ∼620 • C. Both of them could be ascribed to the reduction of Zr 4+ to Zr 3+ , which is confined to the surface of zirconia [22,57,58]. Between profiles (c) and (d), there is a distinct decrease in the temperature of the second peak.…”

Section: Temperature Programmed Reduction and Tpr-xanesmentioning

confidence: 85%

“…5. One complicating factor is the decomposition of surface carbonates, which is known to occur from DRIFTS studies during hydrogen reduction of ceria, zirconia, and related materials [17,22]. Another factor is that sintering most certainly occurs at the higher temperatures, which are certainly above the calcination temperature utilized in catalyst preparation.…”

Section: Temperature Programmed Reduction and Tpr-xanesmentioning

confidence: 97%

“…Chenu et al [22] found that Pt/ZrO 2 catalysts exhibited lower formate band intensities upon adsorption of CO to the activated catalyst in relation to Pt/ceria, and suggested a lower density of defect-associated bridging OH groups (as defined by Binet et al [23] for partially reduced ceria).…”

Section: Introductionmentioning

confidence: 97%

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Water-gas shift: Characterization and testing of nanoscale YSZ supported Pt catalysts

Martinelli

Jacobs

Graham

et al. 2015

Applied Catalysis A: General

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a b s t r a c tNano-scale Y-doped zirconium oxide materials were prepared with high surface areas (150-200 m 2 /g) and small nano-crystallites (<8 nm). A combination of XANES and EXAFS was used to show that ZrO 2 exhibited the tetragonal phase, while the Zr 0.5 Y 0.5 O 1.75 support displayed the cubic phase. A comparison with undoped zirconia suggests that the Zr 0.9 Y 0.1 O 1.95 support was tetragonal in structure. A slight increase in d-spacing observed in HR-TEM for the Zr 0.9 Y 0.1 O 1.95 support relative to undoped ZrO 2 , along with a shift to lower 2Â in XRD, provide evidence that Y-doping caused macrostrain. STEM imaging confirmed that the Pt clusters ranged from 0.5 to 2 nm over all three supports.Catalyst reducibility was explored by H 2 -TPR, XANES at the Zr K-edge, and TPR-XANES at the Pt L III edge. A higher concentration of surface defects for the 0.5%Pt/Zr 0.9 Y 0.1 O 1.95 catalyst relative to 0.5%Pt/ZrO 2 was confirmed by DRIFTS of adsorbed CO, while a greater surface mobility of surface formate was suggested based on forward formate decomposition experiments in steam. The Y-doped Pt promoted catalysts displayed higher water-gas-shift activity relative to the 0.5%Pt/ZrO 2 catalyst when the Y content was at or below 50%, with the best catalyst being 0.5%Pt/Zr 0.9 Y 0.1 O 1.95 .

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Section: Temperature Programmed Reduction and Tpr-xanesmentioning

confidence: 85%

Section: Temperature Programmed Reduction and Tpr-xanesmentioning

confidence: 97%

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Water-gas shift: Characterization and testing of nanoscale YSZ supported Pt catalysts

Martinelli

Jacobs

Graham

et al. 2015

Applied Catalysis A: General

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“…71,72 A reaction mechanism that involves a surface formate intermediate cannot be ruled out. 73 Enhancement of the WGS activity of Pt/CeO 2 has been observed after doping of the oxide with Zr. 74 The doping with zirconia decreases the temperature for the surface reduction step in the WGS process.…”

Section: Wgs On Other Oxide-based Catalystsmentioning

confidence: 96%

H ₂ Production and Fuel Cells

Wang

Rodríguez

2006

Synthesis, Properties, and Applications of Oxide Nanomaterials

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“…Although platinum group metals (PGM) have been employed as the most effective and durable catalysts within most types of low temperature fuel cells [2][3][4], the high price and limited availability of platinum becomes one of the major barriers to commercialization of fuel cells. Research has also shown that supported gold catalysts are very active in the WGS reaction at low temperatures [5,6], thus potential candidates for use in fuel processors.…”

Section: Introductionmentioning

confidence: 99%

Improved Performance of Au/Fe2O3 Catalysts Promoted with ZrO2 and Nb2O5 in the WGS Reaction under Hydrogen-rich Conditions

et al. 2006

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Effect of addition of the ZrO 2 and Nb 2 O 5 promoters on the activity and stability of the Au/Fe 2 O 3 catalysts in the WGS reaction under hydrogen-rich conditions was studied. Results showed that this new catalyst possesses enhanced activity and stability under conditions common in fuel processors. Its CO conversion almost reached the maximum value 99% at 200°C and maintained better stability compared with unmodified samples within 50 h on-stream. Detailed characterization including BET, XRD, HRTEM, XPS, XRF and H 2 -TPR revealed that ZrO 2 and Nb 2 O 5 acted as structural promoters and a strong interaction between ZrO 2 and Nb 2 O 5 existed. The enrichment of Zr and Nb on the surface kept the gold and magnetite particles apart delaying sintering. More active gold sites, larger surface area and smaller magnetite particles were the main reasons for the enhanced performance.

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Water-gas shift: an examination of Pt promoted MgO and tetragonal and monoclinic ZrO2 by in situ drifts

Cited by 96 publications

References 40 publications

Water-gas shift: Characterization and testing of nanoscale YSZ supported Pt catalysts

Water-gas shift: Characterization and testing of nanoscale YSZ supported Pt catalysts

H ₂ Production and Fuel Cells

Improved Performance of Au/Fe2O3 Catalysts Promoted with ZrO2 and Nb2O5 in the WGS Reaction under Hydrogen-rich Conditions

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Water-gas shift: an examination of Pt promoted MgO and tetragonal and monoclinic ZrO2 by in situ drifts

Cited by 96 publications

References 40 publications

Water-gas shift: Characterization and testing of nanoscale YSZ supported Pt catalysts

Water-gas shift: Characterization and testing of nanoscale YSZ supported Pt catalysts

H 2 Production and Fuel Cells

Improved Performance of Au/Fe2O3 Catalysts Promoted with ZrO2 and Nb2O5 in the WGS Reaction under Hydrogen-rich Conditions

Contact Info

Product

Resources

About

H ₂ Production and Fuel Cells