Unusual Catalytic Performance for Selective Acetylene Hydrogenation over Pd Nanoparticles Fabricated on N,O-containing Organic Groups Modified Silica

Wang, Kangjun; Chen, Yangying; Li, Xiaosong; Ding, Huixian

doi:10.1007/s10562-008-9706-z

Cited by 8 publications

(3 citation statements)

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“…Typically, free N-H stretching was reported comprising of two peaks at around 3300 cm −1 and 3200 cm −1 , respectively. [50,51] In our cases, N-H vibrations are not well resolved from the broad SiOH stretching. However, both fresh and annealed NH2-SiO2 exhibits similar widening and stronger intensity of the 3300-3400 cm −1 peak in contrast to bare SiO2.…”

Section: Resultscontrasting

confidence: 58%

Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

et al. 2016

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Metal nanoparticles (NPs) loaded on oxides have been widely used as multifunctional nanomaterials in various fields such as optical imaging, sensors, and heterogeneous catalysis. However, the deposition of metal NPs on oxide supports with high efficiency and homogeneous dispersion still remains elusive, especially when silica is used as the support. Amino-functionalization of silica can improve loading efficiency, but metal NPs often aggregate on the surface. Herein, we report that a facial annealing of amino-functionalized silica can significantly improve the dispersion and enhance the loading efficiency of various metal NPs, such as Pt, Rh, and Ru, on the silica surface. A series of characterization techniques, such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Zeta potential analysis, UV-Vis spectroscopy, thermogravimetric analysis coupled with infrared analysis (TGA-IR), and nitrogen physisorption, were employed to study the changes of surface properties of the amino-functionalized silica before and after annealing. We found that the annealed amino-functionalized silica surface has more cross-linked silanol groups and relatively lesser amount of amino groups, and less positively charges, which could be the key to the uniform deposition of metal NPs during the loading process. These results could contribute to the preparation of metal/oxide hybrid NPs for the applications that require uniform dispersion. Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process." Surface Science 648 (2016): 299-306. AbstractMetal nanoparticles (NPs) loaded on oxides have been widely used as multifunctional nanomaterials in various fields such as optical imaging, sensors, and heterogeneous catalysis. However, the deposition of metal NPs on oxide supports with high efficiency and homogeneous dispersion still remains elusive, especially when silica is used as the support. Amino-functionalization of silica can improve loading efficiency, but metal NPs often aggregate on the surface. Herein, we report that a facial annealing of amino-functionalized silica can significantly improve the dispersion and enhance the loading efficiency of various metal NPs, such as Pt, Rh, and Ru, on the silica surface. A series of characterization techniques, such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Zeta potential analysis, UV-vis spectroscopy, thermogravimetric analysis coupled with infrared analysis (TGA-IR), and nitrogen adsorption, were employed to study the changes of surface properties of the amino-functionalized silica before and after annealing. We found that the annealed amino-functionalized silica surface has more cross-linked silanol groups and relatively lesser amount of amino groups, and less positively charges, which could be the key to the uniform deposition of metal NPs during the loading process. These results could contribute to the preparation of metal/oxide hybrid NPs for the applications that require u...

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Section: Resultscontrasting

confidence: 58%

Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

et al. 2016

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“…Therefore, addition of promoters such as Ag, Co, Cu, Cr, alkali metals, lead acetate, and metal oxides has been done to improve the performance of Pd catalysts . Most of the strategies to enhance SAH involved enhancing the dispersion of Pd, − adding a second metal to form bimetallic catalysts, , utilizing strong metal–support interactions , or introducing an inhibiting gas such as CO or NOx. , Carbon-based supports are becoming increasingly popular for catalytic applications, − and so we have explored the possibility of SAH over one such material, viz., heterofullerenes.…”

Section: Introductionmentioning

confidence: 99%

Tailoring Surface Adsorption and Reactivity of Fullerene-Based Compounds: A Theoretical Probe into C₂–Gas–Fullerene Surface Interactions

Padole

Deshpande

2016

J. Phys. Chem. C

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Density functional theory investigations of palladium and nickel substituted fullerenes (C59M; M = Pd/Ni) were carried out probing the changes in their surface adsorption potential. Structure and bonding in the proposed heterofullerenes were established with insights into metal–carbon bond character, stability, and adsorption potential. C2‑gases were used as probe gases for adsorption tests. Adsorption of acetylene, ethylene, and ethane was studied with different sites over pure and heterofullerenes. Adsorption of acetylene was stronger than the adsorption of ethylene and ethane over C60 with the bridge site sharing hexagonal rings being the energetically favored adsorption site. Surface modification of the fullerene molecule with a foreign metal enhanced the gas-substrate (C2-heterofullerene) interactions. Enhanced surface interactions and differential adsorption behavior of different heterofullerenes made them potential candidates as selective acetylene hydrogenation catalysts. Free energy landscapes for hydrogenation of acetylene and ethylene over all three compounds were developed. The energy barriers for various elementary steps during hydrogenation were significantly smaller over the heterofullerenes when compared to those over C60. Whereas substitution of either metals resulted in a reduction of activation barriers, the activation barriers for post-ethylene formation reactions were smaller over C59Ni making C59Pd a good selective acetylene hydrogenation catalyst.

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“…Different methods have been investigated to suppress ethane formation, which include enhancing the dispersion of palladium, − adding a second metal to form bimetallic catalysts, ,− utilizing the strong metal–support interaction, − and introducing an inhibiting gas such as CO , and NO x . ,− …”

Section: Introductionmentioning

confidence: 99%

Enhanced Selectivity in the Hydrogenation of Acetylene due to the Addition of a Liquid Phase as a Selective Solvent

Hou

Wang

Lan

2013

Ind. Eng. Chem. Res.

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The selective hydrogenation of acetylene is usually a gas-phase reaction. In this work, a liquid phase was introduced as a selective solvent to improve the selectivity to ethylene by coupling absorption to the reaction. The catalyst was 0.01% Pd supported on a low surface area silica. N-methyl-2-pyrrolidone (NMP) was used as a selective solvent, and decane was used as a nonselective solvent for comparison. The liquid-phase hydrogenation was carried out in a stirred flat bottom flask operated in gas continuous and liquid batch mode, and the gas-phase hydrogenation was carried out in a fixed bed reactor. The selectivity to ethylene in the gas-phase hydrogenation was 50–70%. In contrast, the highest selectivity to ethylene in the NMP liquid-phase hydrogenation was increased to 96%, while in decane it had the same value as in the gas phase. In NMP, a low reaction temperature below 80 °C did not give a high selectivity to ethylene because the relatively high ethylene solubility in NMP led to deep hydrogenation and the high acetylene solubility caused more oligomerization. Good catalyst stability was obtained under the optimized conditions of a relatively low space velocity, H2:C2H2 ratio above 10, and reaction temperature above 80 °C. Significant deactivation also occurred in NMP under other conditions due to oligomerization.

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Unusual Catalytic Performance for Selective Acetylene Hydrogenation over Pd Nanoparticles Fabricated on N,O-containing Organic Groups Modified Silica

Cited by 8 publications

References 50 publications

Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

Tailoring Surface Adsorption and Reactivity of Fullerene-Based Compounds: A Theoretical Probe into C₂–Gas–Fullerene Surface Interactions

Enhanced Selectivity in the Hydrogenation of Acetylene due to the Addition of a Liquid Phase as a Selective Solvent

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Unusual Catalytic Performance for Selective Acetylene Hydrogenation over Pd Nanoparticles Fabricated on N,O-containing Organic Groups Modified Silica

Cited by 8 publications

References 50 publications

Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

Tuning surface properties of amino-functionalized silica for metal nanoparticle loading: The vital role of an annealing process

Tailoring Surface Adsorption and Reactivity of Fullerene-Based Compounds: A Theoretical Probe into C2–Gas–Fullerene Surface Interactions

Enhanced Selectivity in the Hydrogenation of Acetylene due to the Addition of a Liquid Phase as a Selective Solvent

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Tailoring Surface Adsorption and Reactivity of Fullerene-Based Compounds: A Theoretical Probe into C₂–Gas–Fullerene Surface Interactions