Synthesis and characterization of supported bimetallic overlayer catalysts

Latusek, Michael P.; Heimerl, Rebecca M.; Spigarelli, Brett P.; Holles, Joseph H.

doi:10.1016/j.apcata.2009.01.038

Cited by 15 publications

(16 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, H 2 uptake increases significantly for 5% Re/Al 2 O 3 and the bimetallic catalysts when chemisorption measurements are performed at 70 and 100°C. Similar observations have been reported for Re/Al 2 O 3[30,45] and supported PGM-Re catalysts[1,2,[27][28][29].…”

supporting

confidence: 86%

“…Catalyst preparation methods have been devised that promote Pd-Re interactions and minimize Re-support interactions. These include catalytic reduction, wherein chemisorbed H on the surface of Pd particles reduces perrhenate ions adsorbed from solution [25][26][27], and the directed deposition technique, wherein a Pd precursor is deposited on reduced Re particles [28][29][30]. Both of these methods, however, require preparation and handling of air-sensitive samples under an inert atmosphere, and the loading of Re (or Pd) is restricted based on the metal surface area of the parent catalyst.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Catalysts for selective hydrogenation of furfural derived from the double complex salt [Pd(NH3)4](ReO4)2 on γ-Al2O3

Thompson

Lamb

2017

Journal of Catalysis

View full text Add to dashboard Cite

a b s t r a c tThe double complex salt [Pd(NH 3 ) 4 ](ReO 4 ) 2 was employed as precursor of supported bimetallic catalysts for selective hydrogenation of furfural. Direct reduction of [Pd(NH 3 ) 4 ](ReO 4 ) 2 on c-Al 2 O 3 in flowing H 2 at 400°C yields bimetallic nanoparticles 1-2 nm in size that exhibit significant interaction between the metals, as evidenced by temperature-programmed hydride decomposition (complete suppression of b-PdH x formation), extended X-ray absorption fine structure spectroscopy at the Pd K and Re L III edges (PdARe distance = 2.72 Å), and scanning transmission electron microscopy with energy dispersive X-ray analysis. In contrast, calcination of [Pd(NH 3 ) 4 ](ReO 4 ) 2 on c-Al 2 O 3 at 350°C in air and subsequent reduction in H 2 at 400°C results in metal segregation and formation of large (>50 nm) supported Pd particles; Re species cover the Pd particles and c-Al 2 O 3 support. A PdRe 1:2 catalyst prepared by sequential impregnation and calcination using HReO 4 and [Pd(NH 3 ) 4 ](NO 3 ) 2 has a similar morphology.The catalyst derived by direct reduction of [Pd(NH 3 ) 4 ](ReO 4 ) 2 on c-Al 2 O 3 exhibits remarkably high activity for selective hydrogenation of furfural to furfuryl alcohol (FAL) at 150°C and 1 atm. Suppression of H 2 chemisorption via elimination of Pd threefold sites, as evidenced by CO diffuse-reflectance infrared Fourier transform spectroscopy, correlates with increased FAL selectivity.

show abstract

supporting

confidence: 86%

Section: Introductionmentioning

confidence: 98%

Catalysts for selective hydrogenation of furfural derived from the double complex salt [Pd(NH3)4](ReO4)2 on γ-Al2O3

Thompson

Lamb

2017

Journal of Catalysis

View full text Add to dashboard Cite

show abstract

“…The SD Re@Pd overlayer catalyst of both particle sizes (2.7 and 6.3 nm respectively [4]) has the lowest activity compared to both the Re@Pd TD and pure Pd catalysts. The Re-Pd and Re@Pd TD have similar reactivity possibly because bulk Pd exists on both samples; on the Re-Pd sample because the metals were independently impregnated on the surface as opposed to an overlayer deposition [13], and on the Re@Pd TD because Pd has been deposited atop the Re three times. Even though Re@Pd TD has less overall Pd than Re@Pd SD, (Table 1) it has been reacted, calcined, and reduced at high temperature multiple times resulting in the possible formation of bulk Pd.…”

Section: Elemental Analysismentioning

confidence: 95%

“…The catalysts synthesized have been previously discussed [4,13]. The catalysts were synthesized via incipient wetness impregnation to be bimetallic overlayer catalysts.…”

Section: Catalyst Synthesismentioning

confidence: 99%

“…In this work, the same catalysts previously published [12,13] were analyzed via X-ray absorption spectroscopy (XAS) to analyze their electronic and structural properties. In addition to the catalysts synthesized by Latusek et al catalysts synthesized and published by Skoglund et al were also studied via XAS to continue their work in determining that the formation of an overlayer dominates reactivity over particle size effects [4].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Particle Size or Electronic Effect? An XAS Study of Re@Pd Overlayer Catalysts

2015

Self Cite

View full text Add to dashboard Cite

Re@Pd (core@overlayer) catalysts are analyzed via X-ray absorption spectroscopy to correlate structural and electronic properties with previous reactivity results. The ethylene hydrogenation turnover frequency of the Re-Pd bimetallic and the Re@Pd catalysts is much lower than that of the pure Pd. A reduction of activity agrees with the computationally predicted properties of the overlayer catalysts and indicates that the overlayer catalysts have been synthesized. The FEFF fitted EXAFS yields a Pd-Pd inter-atomic distance in the Re@Pd SD small particle (2.7 nm) catalyst of 2.79 Å and in the Re@Pd SD large particle (6.3 nm) catalyst of 2.76 Å . The fitted Pd-Pd inter-atomic distance of Pd foil is 2.74 Å . The small particle overlayer Re@Pd SD catalyst is also longer than the Pd-Pd inter-atomic distance seen in the, as synthesized, structureless bimetallic Re-Pd (2.73 Å ). The disparity in calculated inter-atomic distances indicates an electronic effect is being exerted upon the disperse Pd atoms by the larger Re crystals and vice versa. The Pd K-edge and Re L III -edge white line data also show the electronic interaction between the Pd overlayer and the core Re atoms. The Pd white line of the overlayer catalysts shifted up relative to Pd foil indicating Pd d-band broadening as a result of the interaction of Pd with Re. The Re d-band of the overlayer catalysts narrowed, which is evidenced by the decreased white line absorption relative to Re foil. These observed changes in the Pd and Re d-band are consistent with computational predictions for catalysts with overlayer structures. Graphical Abstract

show abstract

Overlayer Bimetallic Catalysts or Particle Size Effects? A Comparison of Re@Pd Catalysts with Different Particle Sizes

Skoglund

Holles

2013

Catal Lett

View full text Add to dashboard Cite

Synthesis and characterization of supported bimetallic overlayer catalysts

Cited by 15 publications

References 35 publications

Catalysts for selective hydrogenation of furfural derived from the double complex salt [Pd(NH3)4](ReO4)2 on γ-Al2O3

Catalysts for selective hydrogenation of furfural derived from the double complex salt [Pd(NH3)4](ReO4)2 on γ-Al2O3

Particle Size or Electronic Effect? An XAS Study of Re@Pd Overlayer Catalysts

Overlayer Bimetallic Catalysts or Particle Size Effects? A Comparison of Re@Pd Catalysts with Different Particle Sizes

Contact Info

Product

Resources

About