Surface Modification of Pd/α-Si3N4 Catalysts Through the Solvent Used During Synthesis. Implications on the CO Chemisorption Properties and Catalytic Performances

Aires, F.J. Cadete Santos; Cervantes, G. Garcia; Bertolini, J.C.

doi:10.1007/s10562-008-9804-y

Cited by 6 publications

(4 citation statements)

References 24 publications

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“…Fourier transformed infrared (FTIR) spectra of adsorbed CO at different temperatures (ranging from room temperature to 300°C) show a very different behaviour for both catalysts. While the CO adsorption states on the Pd/a-Si 3 N 4 prepared in toluene look very similar to those generally measured for silica and/or alumina supported palladium particles, CO chemisorbs less strongly on Pd/a-Si 3 N 4 prepared in water and shows different adsorption sites [51,62]. Comparison of FTIR spectra of CO adsorbed on the Pd/a-Si 3 N 4 -wat catalyst with those obtained by Shin et al [63,64] on Si-modified Pd catalysts suggests that the change of the CO chemisorptive properties observed for the Pd/a-Si 3 N 4 -OAc-wat catalyst is a consequence of the presence of Si ad-atoms at the surface of the Pd particles which block adsorption sites otherwise available in the Pd/a-Si 3 N 4 -OAc-tol catalyst.…”

Section: Influence Of the Solvent Used In The Preparation Of Pd/a-si supporting

confidence: 52%

On the Use of Silicon Nitride in Catalysis

Aires¹,

Bertolini²

2009

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Aires, F. J. Cadete Santos Bertolini, J. C.Silicon nitride has very good thermal and chemical stability, as well as high thermal conductivity compared to oxide materials, which are commonly used as catalyst supports. In exothermic reactions working at high temperature, this facilitates heat transfer and thus limits the formation of local hot spots, which are often responsible for structural modification of the support in addition to sintering of active phases. However, it is only recently that this material has been considered for application as a catalyst support for high temperature reactions. It is now established that silicon nitride can be a good support for catalytically active phases. Its range of application is continually expanding (e.g., partial/total oxidation of methane, hydrogenation and dehydrogenation reactions, photocatalysis, base catalysis, etc.)

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Section: Influence Of the Solvent Used In The Preparation Of Pd/a-si supporting

confidence: 52%

On the Use of Silicon Nitride in Catalysis

Aires¹,

Bertolini²

2009

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“…It is expected that the properties of bimetallic particles correspond to not only to a combination of the properties of both metals but that synergy between them will result in unique chemical and physical new properties. The second metal can strongly modulate the properties of the first metal by decorating specific sites at the surface [16][17][18], by stabilizing the initial catalyst in preventing poisoning [19], by diluting the initial sites at the surface yielding specific atomic ensembles [20,21] with unique controlled properties or by electronic interaction yielding modified electronic structures with a strong influence on reactive gas molecules adsorption and/or dissociation [22,23].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Investigation of Pd and Bimetallic Pd-Sn Nanocrystals on γ-Al2O3

et al. 2021

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One of the key factors for producing highly dispersed controlled nanoparticles is the method used for metal deposition. The decomposition of metal-organic precursors is a good method for deposition of metal nanoparticles with very small sizes and narrow size distributions on the surface of various supports. The preparation process of Pd and bimetallic Pd-Sn nanoparticles supported onto γ‑Al2O3 is considered. The samples were prepared by diffusional co-impregnation of the γ‑Al2O3 support by using organometallic Pd(acac)2 and Sn(acac)2Cl2 precursors. To achieve the formation of Pd and bimetallic Pd-Sn nanoparticles on the support surface, the synthesized samples were then subjected to thermal decomposition under Ar (to decompose the organometallic bound to the surface while keeping the formed nanoparticles small) followed by an oxidation in O2 (to eliminate the organic compounds remaining on the surface) and a reduction in H2 (to reduce the nanoparticles oxidized during the previous step). A combination of methods (ICP-OES, TPR-H2, XPS, TEM/EDX) was used to compare the physical-chemical properties of the synthesized Pd and bimetallic Pd-Sn nanoparticles supported on the γ‑Al2O3. The three samples exhibit narrow size distribution with a majority on nanoparticles between 3 and 5 nm. Local EDX measurements clearly showed that the nanoparticles are bimetallic with the expected chemical composition and the measured global composition by ICP-OES. The surface composition and electronic properties of Pd and Sn on the γ-Al2O3 support were investigated by XPS, in particular the chemical state of palladium and tin after each step of thermal decomposition treatments (oxidation, reduction) by the XPS method has been carried out. The reducibility of the prepared bimetallic nanoparticles was measured by hydrogen temperature programmed reduction (TPR-H2). The temperature programmed reduction TPR-H2 experiments have confirmed the existence of strong surface interactions between Pd and Sn, as evidenced by hydrogen spillover of Pd to Sn (Pd-assisted reduction of oxygen precovered Sn). These results lead us to propose a mechanism for the formation of the bimetallic nanoparticles.

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“…), in particular for the catalytic oxidation of methane and alcohols. [21][22][23][24][25] In order to better control the size of the particle and avoid the sintering of the metals which inherently occurs on non-porous supports, development of porosity is required. The Polymer-Derived Ceramics (PDCs) route has been widely investigated to prepare non-oxide ceramics with a tailored porosity.…”

Section: A Introductionmentioning

confidence: 99%

Monodisperse platinum nanoparticles supported on highly ordered mesoporous silicon nitride nanoblocks: superior catalytic activity for hydrogen generation from sodium borohydride

et al. 2015

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Late transition metal nanoparticles have attracted considerable interest for catalytic applications. Their immobilization over supports with tailored porosity is advantageous for nanosizing metal nanoparticles and avoiding their agglomeration which is known to bring a serious issue to the catalytic performance. Herein, ordered mesoporous silicon nitride (Si3N4) nanoblocks with hexagonal symmetry of the pores, high specific surface areas (772.4 m 2 .g -1 ) and pore volume (1.19 cm 3 .g -1 ) are synthesized by nanocasting using perhydropolysilazane as precursor. Then, Si3N4 nanoblocks are used as supports to synthesize platinum nanoparticles (Pt NPs) by precursor wet impregnation. Detailed characterizations by TEM show that monodispersed spherical Pt NPs with a 6.77 nm diameter are successfully loaded over nanoblocks to generate nanocatalysts. The latter are subsequently used for the catalytic hydrolysis of sodium borohydride (NaBH4). A hydrogen generation rate of 13.54 L.min -1 .gPt -1 is measured. It is notably higher than the catalytic hydrolysis using Pt/CMK-3 nanocatalysts (2.58 L.min -1 .gPt -1 ) most probably due to the textural properties of the Si3N4 supports associated with the intrinsic properties of Si3N4. This leads to an attractive nanocatalyst in pursuit of practical implementation of B-/N-based chemical hydrides as a hydrogen source for fuel cell application.

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Surface Modification of Pd/α-Si3N4 Catalysts Through the Solvent Used During Synthesis. Implications on the CO Chemisorption Properties and Catalytic Performances

Cited by 6 publications

References 24 publications

On the Use of Silicon Nitride in Catalysis

On the Use of Silicon Nitride in Catalysis

Preparation and Investigation of Pd and Bimetallic Pd-Sn Nanocrystals on γ-Al2O3

Monodisperse platinum nanoparticles supported on highly ordered mesoporous silicon nitride nanoblocks: superior catalytic activity for hydrogen generation from sodium borohydride

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