Bifunctional H2WO4/TS-1 catalysts for direct conversion of cyclohexane to adipic acid: Active sites and reaction steps

Dai, Jiangdong; Zhong, Wenzhou; Yi, Wen-Jun; Liu, Mengqiao; Mao, Liang; Xu, Qiong; Yin, Dulin

doi:10.1016/j.apcatb.2016.04.005

Cited by 84 publications

(53 citation statements)

References 65 publications

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“…3 show the characteristic MFI absorption bands e at 450, 550, 801, 1100 and 1220 cm 1 , which can be ascribed to the bend, symmetry and asymmetry stretch of SieO bond [12] e for all the samples. In addition to these charac-teristic MFI absorption bands, a strong absorption band at 960 cm 1 , which is characteristic of the SieOeTi stretching vibra-tion [42] in the titanium containing samples can be observed. The presence and strength of this peak are the first indications of the existence of the titanium atoms in the tetrahedral framework po-sition, particularly when compared to the spectra of the pure sili-cate material, which is devoid of this band.…”

Section: Spectroscopic Analysismentioning

confidence: 98%

On the synthesis and performance of hierarchical nanoporous TS-1 catalysts

Adedigba

Sankar

Catlow

et al. 2017

Microporous and Mesoporous Materials

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Hierarchical TS-1 zeolite was successfully prepared using chitosan as a sacrificial template. The X-ray diffraction showed that the presence of chitosan with the synthesis precursor had no deleterious effect on the crystallinity and phase purity of this zeolite. X-ray absorption spectroscopy at the Ti K-edge, FTIR and Raman spectroscopies revealed the titanium ions in the zeolite structure have predominantly tetrahedral coordination. However, it appears that the higher chitosan content in the synthesis gel imparted some hydrophilic character to the TS-1 system. Furthermore, the technique adopted for the preparation of the synthesis gel e e.g partially dried or fully dried e appears to affect the amount of framework titanium in the zeolite structure. The calcined form of the chitosan templated TS-1 zeolites exhibited higher cyclohexene conversion compared to the TS-1 material synthesised without this template , but these catalysts showed lower selectivity for cyclohexene epoxide.

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Section: Spectroscopic Analysismentioning

confidence: 98%

On the synthesis and performance of hierarchical nanoporous TS-1 catalysts

Adedigba

Sankar

Catlow

et al. 2017

Microporous and Mesoporous Materials

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“…In WO3 nanosheets, the WO3 grew along the [002] direction, resulting in the increase of W=O percentage. and 944 cm -1 are present, which might be ascribed to the characteristic stretching vibrations of W 6+ -O and terminal W 6+ -O in orthorhombic WO3•H2O [38,39]. Furthermore, WO3 nanosheets were probed by X-ray photoelectron spectroscopy (XPS).…”

Section: Raman Ftir and Optical Propertiesmentioning

confidence: 99%

Crystal transformation of 2D tungstic acid H2WO4 to WO3 for enhanced photocatalytic water oxidation

Zhou²,

Liu

et al. 2018

Journal of Colloid and Interface Science

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New photocatalytic materials for stable reduction and/or oxidization of water by harvesting a wider range of visible light are indispensable to achieve high practical efficiency in artificial photosynthesis. In this work, we prepared 2D WO3•H2O and WO3 nanosheets by an one-pot hydrothermal method and sequent calcination, focusing on the effects of crystal transformation on band structure and photocatalytic performance for photocatalytic water oxidation in the presence of electron acceptors (Ag +) under simulated solar light irradiation. The as-prepared WO3 nanosheets exhibit enhanced rate of photocatalytic water oxidation, which is 6.3 and 3.6 times higher than that of WO3•H2O nanosheets and commercial WO3, respectively. It is demonstrated that the releasing of water molecules in the crystal phase of tungstic acid results in transformation of the crystal phase from orthorhombic WO3•H2O to monoclinic WO3, significantly improving the activity of photocatalytic water oxidation in the presence of Ag + because the shift-up of conduction band of WO3 matches well with the electrode potential of Ag + /Ag(s), leading to efficient separation of photoinduced electrons and holes in pure WO3 nanosheets.

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“…The Ti 2p 3/2 spectra are shown in Figure 8. The peak at the binding energy (BE) at around 460 eV belonged to the tetrahedral Ti in the framework, and the peak at the BE at 458 eV turned out to be the extraframework Ti in the catalyst [58][59][60][61][62]. As shown in Figure 8, the single peak at the BE at 460 eV of the TS-1 catalyst demonstrated that almost only framework Ti species existed.…”

Section: Inductively Coupled Plasma (Icp) and X-ray Photoelectron Spementioning

confidence: 96%

Direct Hydroxylation of Benzene to Phenol over TS-1 Catalysts

et al. 2018

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We synthesized a TS-1 catalyst to directly hydroxylate benzene to phenol with H 2 O 2 as oxidant and water as solvent. The samples were characterized by FT-IR (Fourier Transform Infrared), DR UV-Vis (Diffused Reflectance Ultraviolet Visible), XRD (X-ray diffraction), SEM(scanning electron microscope), TEM (Transmission Electron Microscope), XPS (X-ray photoelectron spectroscopy), ICP (inductively coupled plasma spectrum), and N 2 adsorption-desorption. A desirable phenol yield of 39% with 72% selectivity was obtained under optimized conditions: 0.15 g (0.34 to the mass of benzene) TS-1, 5.6 mmol C 6 H 6 , reaction time 45 min, 0.80 mL H 2 O 2 (30%), 40.0 mL H 2 O, and reaction temperature 70 • C. The reuse of the TS-1 catalyst illustrated that the catalyst had a slight loss of activity resulting from slight Ti leaching from the first run and then kept stable. Almost all of the Ti species added in the preparation were successfully incorporated into the TS-1 framework, which were responsible for the good catalytic activity. Extraframework Ti species were not selective for hydroxylation.

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Bifunctional H2WO4/TS-1 catalysts for direct conversion of cyclohexane to adipic acid: Active sites and reaction steps

Cited by 84 publications

References 65 publications

On the synthesis and performance of hierarchical nanoporous TS-1 catalysts

On the synthesis and performance of hierarchical nanoporous TS-1 catalysts

Crystal transformation of 2D tungstic acid H2WO4 to WO3 for enhanced photocatalytic water oxidation

Direct Hydroxylation of Benzene to Phenol over TS-1 Catalysts

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