Synthesis of Nano-Sized Platinum Metal Particles on Ti-Containing Mesoporous Silica Using Microwave-Assisted Deposition Method

Shironita, Sayoko; Takasaki, Tomoya; Kamegawa, Takashi; Mori, Kohsuke; Yamashita, Hiromi

doi:10.1007/s11244-009-9414-y

Cited by 19 publications

(7 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ti-containing mesoporous silica was prepared according to a previous report by a sol-gel method using tetraethoxysilane (TEOS: Si(OEt) 4 ) as a silica source, titanium tetraisopropoxide (TPOT: Ti(O i Pr) 4 ) as a titanium source and dodecylamine hydrochloride (DDA: CH 3 (CH 2 ) 11 NH 3 Cl) as a template (Ti-HMS, Si : Ti ¼ 99 : 1). 35 After the Ti-HMS (0.489 g) was suspended in a mixed aqueous solution (20 cm 3 ) of NiSO 4 $6H 2 O (0.023 g) and 50 mM HCl aqueous solution (12 mM, 5 cm 3 ) of PdCl 2 , the pH of the suspension was adjusted to 10 by aqueous ammonia. After bubbling with Ar, the suspension was photoirradiated by a 100 W high-pressure mercury arc for 20 h. After filtration and washing with distilled water, the resultant powder was dried at 373 K overnight and calcined at 723 K for 3 h in air and then reduced by H 2 at 773 K for 60 min, resulting in the formation of PAD-PdNi/Ti-HMS (Ni/Pd ¼ 1.5).…”

Section: Experimental Preparation Of Catalystsmentioning

confidence: 99%

Enhanced hydrogenation activity of nano-sized Pd–Ni bimetal particles on Ti-containing mesoporous silica prepared by a photo-assisted deposition method

et al. 2012

Self Cite

View full text Add to dashboard Cite

A facile photo-assisted deposition (PAD) for the synthesis of highly dispersed and small Pd-Ni bimetal nanoparticles with a narrow size distribution has been developed by combining mesoporous silica materials including a single-site Ti-oxide moiety (Ti-HMS) as a promising photo-responsive catalyst support. Under UV-light irradiation, both Pd and Ni precursors can be deposited directly on the photoexcited tetrahedrally coordinated Ti-oxide moiety within the silica frameworks, and subsequently reduced with H 2 to generate the nano-sized Pd-Ni bimetal particles. Compared with individual Pd or Ni-loaded Ti-HMS (Pd or Ni/Ti-HMS) prepared by PAD and PdNi/Ti-HMS prepared by the conventional impregnation (Imp) technique, the PdNi/Ti-HMS prepared by PAD showed a strong synergistic effect in the catalytic hydrogenation of nitrobenzene (NB) to aminobenzene (AB). It was also found that the hydrogenation activity reached a maximum at the molar ratio of Ni/Pd ¼ 1.5, while further increases in Ni loading amount gradually decreased the catalytic activity.

show abstract

Section: Experimental Preparation Of Catalystsmentioning

confidence: 99%

Enhanced hydrogenation activity of nano-sized Pd–Ni bimetal particles on Ti-containing mesoporous silica prepared by a photo-assisted deposition method

et al. 2012

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, it can be considered that titanium moieties within silica matrices interact with microwaves and are heated selectively, resulting in the formation of a heatspot on titanium moieties acting as deposition sites. 33,34 A TEM image also revealed the formation of CNTs on Co-Mo/Ti(10)-MSTF as shown in Fig. 7.…”

Section: Resultsmentioning

confidence: 85%

“…Moreover, our group has reported that metallic particles with a mean diameter of 3-4 nm were successfully formed on Ti-containing mesoporous silica under microwave irradiation. 33,34 Interaction between isolated titanium moieties within the silica frameworks and microwaves enabled the immobilization of highly-dispersed metallic particles on the Ti-sites.…”

Section: Introductionmentioning

confidence: 99%

Design of superhydrophobic surfaces by synthesis of carbon nanotubes over Co–Mo nanocatalysts deposited under microwave irradiation on Ti-containing mesoporous silica thin films

Horiuchi

Shimizu

Kamegawa

et al. 2011

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

The superhydrophobic surface has been designed by the synthesis of carbon nanotubes (CNTs) on Ti-containing mesoporous silica thin films (Ti-MSTFs) with Co-Mo binary nanocatalysts. The active Co-Mo catalysts have been successfully deposited on Ti-MSTFs under microwave irradiation. SEM and TEM observations after CNT synthesis revealed that surfaces of Ti-MSTFs were densely covered with CNTs having a diameter of 15 nm. Raman spectra indicated that the undesired structural defects in the carbon network of the synthesized CNTs, which would lead to the formation of hydroxyl groups, were scarce. Interestingly, hydrophobic properties of samples after CNT synthesis were enhanced with increasing titanium concentration of Ti-MSTF, and the water contact angle reached up to 165° on Ti-MSTF with a titanium concentration of 10 at%. The combination of dispersed titanium oxide moieties within the silica frameworks and the microwave irradiation made a great contribution to deposit active Co-Mo catalysts responsible for the formation of well-dense CNTs.

show abstract

“…The overidentification of microwave specific effects has been attributed to experimental difficulties in accurately measuring temperature within the reaction vessel. Subsequently, as the technology for accurately determining temperature in the microwave improved, studies of homogeneous reactions were reported that clearly showed microwave specific rate enhancement. − …”

Section: Introductionmentioning

confidence: 99%

Direct Measurement of the Selective Microwave-Induced Heating of Agglomerates of Dipolar Molecules: The Origin of and Parameters Controlling a Microwave Specific Superheating Effect

et al. 2021

View full text Add to dashboard Cite

Agglomerates of polar molecules in nonpolar solvents are selectively heated by microwave radiation. The magnitude of the selective heating was directly measured by using the temperature dependence of the intensities of the Stokes and anti-Stokes bands in the Raman spectra of p-nitroanisole (pNA) and mesitylene. Under dynamic heating conditions, a large apparent temperature difference (ΔT) of over 100 °C was observed between the polar pNA solute and the nonpolar mesitylene solvent. This represents the first direct measurement of the selective microwave heating process. The magnitude of the selective microwave heating was affected by the properties of the agglomerated pNA. As the concentration of the pNA increases, the magnitude of the selective heating of the pNA was observed to decrease. This is explained by the tendency of the pNA dipoles to orient in an antiparallel fashion in the aggregates as measured by the Kirkwood g value, which decreased with increasing concentration. This effect reduces the net dipole moment of the agglomerates, which decreases the microwave absorption. After the radiation was terminated, the effective temperature of the dipolar molecules returned slowly to that of the medium. The slow heat transfer was modeled successfully by treating the solutions as a biphasic solvent/solute system. Based on modeling and the fact that the agglomerate can be heated above the boiling temperature of the solvent, an insulating layer of solvent vapor is suggested to form around the heated agglomerate, slowing convective heat transfer out of the agglomerate. This is an effect unique to microwave heating.

show abstract

Synthesis of Nano-Sized Platinum Metal Particles on Ti-Containing Mesoporous Silica Using Microwave-Assisted Deposition Method

Cited by 19 publications

References 24 publications

Enhanced hydrogenation activity of nano-sized Pd–Ni bimetal particles on Ti-containing mesoporous silica prepared by a photo-assisted deposition method

Enhanced hydrogenation activity of nano-sized Pd–Ni bimetal particles on Ti-containing mesoporous silica prepared by a photo-assisted deposition method

Design of superhydrophobic surfaces by synthesis of carbon nanotubes over Co–Mo nanocatalysts deposited under microwave irradiation on Ti-containing mesoporous silica thin films

Direct Measurement of the Selective Microwave-Induced Heating of Agglomerates of Dipolar Molecules: The Origin of and Parameters Controlling a Microwave Specific Superheating Effect

Contact Info

Product

Resources

About