Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

Gutiérrez, Luis Felipe Higuita; Hamoudi, Safia; Belkacemi, Khaled

doi:10.3390/catal1010097

Cited by 97 publications

(72 citation statements)

References 243 publications

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“…For this method, the surface functionalization of the support with amine groups is important for anchoring gold nanoparticles due to strong interaction between them. The amine groups can be introduced onto the support either during synthesis [67] or by postgrafting [68]. Both loading and distribution of amine groups, which in turn determine the loading and distribution of gold nanoparticles to a great extent, are closely related to the nature of the support.…”

Section: Two-step Methodsmentioning

confidence: 99%

Understanding the synergistic effects of gold bimetallic catalysts

Wang

Liu

Mou

et al. 2013

Journal of Catalysis

187

107

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Section: Two-step Methodsmentioning

confidence: 99%

Understanding the synergistic effects of gold bimetallic catalysts

Wang

Liu

Mou

et al. 2013

Journal of Catalysis

187

107

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“…The importance of surface area density in heat and mass transfer processes is well known and for this reason it is also described as Transfer Area Density [17]. In Figure 25, the measured BET surface area of the silica support for the microwaved sample is 234 m 2 The variation of XRD-based catalyst size with catalyst loading shown in Figure 26 indicates that at all catalyst loadings, microwave processing provides smaller catalyst size when compared with the other processes, especially at high catalyst loadings. Even after taking into account a slight increase in catalyst size following heat treatment at 600 °C using Method-C (see Table 1), the microwave method still provides the smallest catalyst size.…”

Section: Summary Of Catalyst Characteristicsmentioning

confidence: 99%

“…There are several strategies available to achieve a small catalyst size [1][2][3][4][5][6][7]. Relevant to this study, the methods include processing under a nitric oxide atmosphere during the decomposition of the catalyst precursor nitrate salt [4,7] or physical agitation [7].…”

Section: Heterogeneous Catalysts and Catalyst Supportmentioning

confidence: 99%

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Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Akay

2016

Catalysts

106

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Abstract:A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV) induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m 2 /g and X-ray Diffraction (XRD)-based catalyst size controlled in the range of 1-10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied) when the catalyst/support molar ratio is typically 0.1-2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) studies, the micro-and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6-2 nm thick lamellar sheets of 10-100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm 3 . A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano-particles dispersed in water which also contains the catalyst precursor nitrate salt. This support-catalyst precursor fluid must have a sufficiently low viscosity but high elastic modulus (high extensional viscosity) to form films and bubbles when exposed to processing energy sources such as microwave, thermal, ultra-sound or UV-radiation or their combination. The micro-to-nano structures of the catalyst system are essentially formed at an early stage of energy input. It is shown that the primary particles of silica are transformed to a proto-silica particle state and form lamellar structures with the catalyst precursor. While the nano-structure is forming, water is evaporated leaving a highly porous solid support-catalyst precursor which then undergoes decomposition to form a silica-catalyst oxide system. The final catalyst system is obtained after catalyst oxide reduction. Although the XRD-based catalyst size changes slightly during the subsequent heat treatments, the nano-structure of the catalyst system remains substantially unaltered as evaluated through TEM images. Howev...

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“…In general, the selective hydrogenation of the C=C bond of CAL over different heterogeneous catalysts are summarized in Table S1. In order to obtain metal-based catalysts with superior performance, the best method is to prepare evenly dispersed metal nanoparticles on a large specific surface area support, for instance, mesoporous carbon, silica, alumina, and so on [24,[33][34][35]. Particularly, ordered mesoporous siliceous material SBA-15 is widely used as the support candidate due to its suitable pore size and large pore volume as well as high specific surface area [36,37].…”

Section: Scheme 1 Reaction Routes For the Hydrogenation Of Cinnamaldmentioning

confidence: 99%

Improvement Effect of Ni to Pd-Ni/SBA-15 Catalyst for Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

et al. 2018

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Abstract:A series of Pd-Ni bimetallic catalysts supported on SBA-15 (0.2%Pd-x%Ni/SBA-15, x = 0.4, 0.7, and 1.2) were prepared through the impregnation method combined with the NaBH 4 reduction method. X-ray diffraction (XRD), N 2 adsorption-desorption, X-ray photoemission spectroscopy (XPS) and transmission electron microscope (TEM) were used to characterize the prepared catalysts. All the synthesized catalysts were evaluated for the liquid-phase hydrogenation of cinnamaldehyde (CAL). The addition of Ni obviously enhanced the CAL conversion and selectivity of C=C hydrogenation to hydrocinnamaldehyde (HALD) over the 0.2%Pd-x%Ni/SBA-15 catalysts. Meanwhile, 0.2%Pd-1.2%Ni/SBA-15 showed the best performance with 96.3% conversion and 87.8% selectivity toward HALD. This improvement was attributed to the synergistic effect between the Pd and Ni nanoparticles, enhancing the dispersion of Pd metal particles and increasing the content of surface Pd 0 species. In addition, the influences of a few reaction factors including H 2 pressure, reaction temperature, and reaction time were studied over 0.2%Pd-1.2%Ni/SBA-15.

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Synthesis of Gold Catalysts Supported on Mesoporous Silica Materials: Recent Developments

Cited by 97 publications

References 243 publications

Understanding the synergistic effects of gold bimetallic catalysts

Understanding the synergistic effects of gold bimetallic catalysts

Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

Improvement Effect of Ni to Pd-Ni/SBA-15 Catalyst for Selective Hydrogenation of Cinnamaldehyde to Hydrocinnamaldehyde

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