Dendrimer-mediated synthesis of subnanometer-sized Rh particles supported on ZrO2

Siani, Attilio; Alexeev, Oleg S.; Deutsch, D. Samuel; Monnier, John R.; Fanson, Paul T.; Hirata, Hirohito; Matsumoto, Shinichi; Williams, Christopher T.; Amiridis, Michael D.

doi:10.1016/j.jcat.2009.06.025

Cited by 22 publications

(15 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Extended X-ray absorption fine structure (EXAFS) measurements have thus been carried out to clarify a possible structure of the metallic Au 0 species. However, no meaningful information can be obtained (not shown), possibly due to the poor contrast between gold and ZrO 2 support (in transmission mode) or the strong interference of fluorescent signal of ZrO 2 support (in fluorescent mode) . We then sought to use a low-temperature CO titration approach to elucidate the intricate nature of the TEM-invisible Au species.…”

Section: Resultsmentioning

confidence: 99%

Efficient Subnanometric Gold-Catalyzed Hydrogen Generation via Formic Acid Decomposition under Ambient Conditions

et al. 2012

View full text Add to dashboard Cite

Formic acid (FA) has tremendous potential as a safe and convenient source of hydrogen for sustainable chemical synthesis and renewable energy storage, but controlled and efficient dehydrogenation of FA by a robust solid catalyst under ambient conditions constitutes a major challenge. Here, we report that a previously unappreciated combination of subnanometric gold and an acid-tolerant oxide support facilitates the liberation of CO-free H(2) from FA. Applying an ultradispersed gold catalyst comprising TEM-invisible gold subnanoclusters deposited on zirconia to a FA-amine mixture affords turnover frequencies (TOFs) up to 1590 per hour and a turnover number of more than 118,400 at 50 °C. The reaction was accelerated at higher temperatures, but even at room temperature, a significant H(2) evolution (TOFs up to 252 h(-1) after 20 min) can still be obtained. Preliminary mechanistic studies suggest that the reaction is unimolecular in nature and proceeds via a unique amine-assisted formate decomposition mechanism on Au-ZrO(2) interface.

show abstract

Section: Resultsmentioning

confidence: 99%

Efficient Subnanometric Gold-Catalyzed Hydrogen Generation via Formic Acid Decomposition under Ambient Conditions

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Immobilization of the dendrimers on solid supports, for example, ZrO 2 , provided a reusable, heterogeneous catalytic system. 50 In addition to macromolecular polymer and dendrimer NP stabilizers, small molecule "ligands" are attractive stabilizers as their steric and electronic properties can be carefully designed and modified to provide a molecular-level understanding of the role of the stabilizer with respect to catalytic function. Rh NPs coated with various bipyridine ligands (2,2′-, 3,3′-, and 4,4′-bipy, see Figure 7) dispersed in [C 4 mim][PF 6 ] were found to effectively catalyze the hydrogenation of arenes.…”

Section: Acs Catalysismentioning

confidence: 99%

Advances in the Rational Design of Rhodium Nanoparticle Catalysts: Control via Manipulation of the Nanoparticle Core and Stabilizer

2012

View full text Add to dashboard Cite

This review describes some of the fascinating advances in the field of rhodium nanoparticle (NP) catalysis that have emerged in recent years. The examples described are categorized according to the research approach applied, involving either direct engineering of the NP core (size/shape control) or manipulating the NP via a stabilizer and/or solvent. Consequently, both surface-immobilized heterogeneous Rh NP and solvent dispersed Rh NP catalysts are included. The interplay between relevant parameters and the catalytic properties of Rh NPs are discussed, with a focus on design, function, and mechanisms. Rh NP-based multifunctional systems are also described. The approaches used to probe Rh NP catalysts at a molecular level and possible future research trends are highlighted.

show abstract

“…Noble metal nanoparticles with controlled size, shape, and surface structure are of fundamental importance because of their unique properties and numerous promising applications. , Colloidal metal particles have been typically prepared by the reduction of metal salts in the presence of stabilizing or capping materials such as polymers or surfactants. − Metal nanoparticles such as rhodium (Rh) − and palladium (Pd) − have been prepared by various methods, such as photochemical reduction, − chemical reduction, , thermal decomposition, and so on. Much attention has been paid to the size and shape control of noble metal nanoparticles by tuning the crystal growth kinetics in solution-phase synthesis, since the size and shape of metal nanoparticles depend on their kinetics of the nucleation and growth process.…”

Section: Introductionmentioning

confidence: 99%

Nucleation and Growth of Metal Nanoparticles during Photoreduction Using In Situ Time-Resolved SAXS Analysis

2011

View full text Add to dashboard Cite

Formation of metal nanoparticles (rhodium (Rh) and palladium (Pd) nanoparticles) in an aqueous ethanol solution of poly(N-vinyl-2-pyrrolidone) (PVP) by photoreduction was monitored by means of in situ and time-resolved small-angle X-ray scattering (SAXS) measurements. The kinetics of association process (nucleation, growth, and particle coalescence) of metal atoms to produce metal nanoparticles was successfully evaluated by the quantitative SAXS analysis for the number-average of radius (R 0), number of particles (n p), standard deviation in radius (σR/R 0), and total volume (V p) of metal nanoparticles produced by the photoreduction. The time evolution of particle size, number of particles, and particle size distribution indicated that the formation of Rh nanoparticles predominantly follows an autocatalytic reduction–nucleation process before the onset of Ostwald ripening-based growth. On the other hand, in the formation of Pd nanoparticles, the reduction–nucleation process occurred significantly faster at the early stage of the reaction, and the dominant growth of Pd nanoparticles subsequently proceeded via an Ostwald ripening-based growth mechanism. It was also found that the rate of nucleation and growth during the metal particle formation is strongly affected by the initial metal concentration and the addition of NaCl.

show abstract

Dendrimer-mediated synthesis of subnanometer-sized Rh particles supported on ZrO2

Cited by 22 publications

References 70 publications

Efficient Subnanometric Gold-Catalyzed Hydrogen Generation via Formic Acid Decomposition under Ambient Conditions

Efficient Subnanometric Gold-Catalyzed Hydrogen Generation via Formic Acid Decomposition under Ambient Conditions

Advances in the Rational Design of Rhodium Nanoparticle Catalysts: Control via Manipulation of the Nanoparticle Core and Stabilizer

Nucleation and Growth of Metal Nanoparticles during Photoreduction Using In Situ Time-Resolved SAXS Analysis

Contact Info

Product

Resources

About