Synthesis, characterization, and catalytic function of novel highly dispersed tungsten oxide catalysts on mesoporous silica

Herrera, José E.; Kwak, Ja Hun; Hu, Jian Zhi; Wang, Yong; Peden, Charles H. F.; Macht, Josef; Iglesia, Enrique

doi:10.1016/j.jcat.2006.01.034

Cited by 132 publications

(127 citation statements)

References 44 publications

Supporting

Mentioning

117

Contrasting

Unclassified

Order By: Relevance

“…1A. It is distinct that low-angle X-ray diagrams of all samples are wellresolved and exhibit three characteristic peaks corresponding to Bragg reflections on (100), (110), and (200) planes of mesoporous silicate materials, revealing the maintenance of original structure of p6 mm hexagonal symmetry [33]. In addition, the intensity of diffraction peak (100) of samples somewhat declines along with the increment of titanium additive dosage, attributing to the gradual destruction of long-range ordering of hexagonal pore structure [34] or the variation in electron density of titanium-incorporated materials, similar to tungsten incorporated MCM-41 [35].…”

Section: Resultsmentioning

confidence: 88%

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Chang

Wang

Luo

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

View full text Add to dashboard Cite

h i g h l i g h t s• A series of tungsten-titaniumcocontained SBA15 composites were fabricated by a simple synthetic route.• These samples showed enhanced catalytic performance in comparison to those comprising bare tungsten or titanium component.• The enhancement of photocatalytic behavior under visible-light irradiation was discussed. t r a c tA facile and one-step hydrothermal procedure was adopted to fabricate a series of W-Ti-SBA15 composites (WTS). These as-prepared composites were systematically characterized by a collection of analytic and spectroscopic techniques. It was found that dual phases of titanium and tungsten species coexisted in mesoporous structures of p6 mm hexagonal symmetry. In addition, these composites were visible-light responsive and exhibited enhanced photocatalytic capability toward degradation of Rhodamine B (RhB) and 2,4-dichlorophenol (2,4-DCP) upon visible-light irradiation in comparison to samples containing single component of titanium or tungsten species. Specifically, the best candidate, sample 8%WTS0.7, had the largest apparent reaction rate constant that was nearly 1.2, 2.1, 2.2, and 5.7 times as high as those of 8%WS, TS0.7, WO 3 /TiO 2 , and N-TiO 2 , respectively. The enhancement of photocatalytic performance was mainly attributed to the well-matched band structures of both components and strengthened visiblelight adsorption ability, originating from the combination of titania with highly acidic WO 3 in SBA15 matrix with large specific surface areas. Active radical species were detected by trapping experiments and a possible photocatalytic mechanism was thus proposed.

show abstract

Section: Resultsmentioning

confidence: 88%

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Chang

Wang

Luo

et al. 2016

Colloids and Surfaces A: Physicochemical and Engineering Aspect

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5][6][7][8][9][10][11] These previous studies have established a good understanding of the performance of these catalysts as a function of WO 3 domain size and support effects. The acid site reactivity of WO 3 catalysts is commonly probed using the selective transformation of methanol (MeOH) to dimethyl ether (DME).…”

Section: Introductionmentioning

confidence: 99%

Investigating the Influence of Au Nanoparticles on Porous SiO₂–WO₃ and WO₃ Methanol Transformation Catalysts

et al. 2016

View full text Add to dashboard Cite

American Chemical SocietyDepuccio, DP.; Ruiz-Rodríguez, L.; Rodriguez-Castellon, E.; Botella Asuncion, P.; López Nieto, JM.; Landry, CC. (2016) AbstractAnalyzing the structural and chemical properties of materials at the interface of metal nanoparticles and metal oxide supports is important for catalytic applications. Tungsten oxide (WO 3 ) is a widely studied catalyst, but changing the catalytic reactivity at the surface of this oxide with metal nanoparticles is of interest. In this work, we sought to modify the redox properties of porous WO 3 and SiO 2 -WO 3 catalysts with sonochemically deposited gold nanoparticles (Au NPs) in order to access and study this reaction pathway. Characterization using powder X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and inductively-coupled plasma optical emission spectroscopy (ICP-OES) confirmed that crystalline Au NPs with diameters of 5 -12 nm were distributed throughout the catalysts. Temperature-programmed desorption (TPD) was used to probe the surface acidity of the catalysts. The physic-chemical characteristics of catalysts have been also discussed by considering the catalytic performance of these materials in the aerobic transformation of methanol. Catalysts containing nanocrystalline WO 3 but no Au NPs displayed very high selectivity to DME (> 60%) at all conversions with minor oxidation reactivity, which highlighted the acidic nature of these catalysts. No effect on the acidity of the catalysts was observed by TPD when Au NPs were loaded in the catalysts. The reducibility of the crystalline WO 3 species, however, increased significantly due to the interaction with Au NPs, as observed by temperature-programmed reduction (TPR). In the gas-phase transformation of MeOH under aerobic conditions, catalysts modified with Au NPs showed greater activity compared to non-modified catalysts. In addition, oxidation selectivity to products such as methyl formate as well as formaldehyde, dimethoxymethane, and carbon oxides became heavily favored with only minor dehydration selectivity. The redox properties of these WO 3 catalysts could be tuned by changing the Au loading. More labile lattice oxygen and enhanced redox properties at the surface of WO 3 modified with Au NPs clearly altered these traditional dehydration catalysts to potential oxidation catalysts. Thus, modification of WO 3 with Au is an effective way to expand the MeOH transformation product distribution beyond DME to other useful, oxidized products not typically observed over pure WO 3 .

show abstract

“…1A. All samples display three pronounced diffraction peaks corresponding to (1 0 0), (1 1 0), and (2 0 0) reflections of mesoporous silicon-based materials, indicating that the involvement of tungsten species into SBA15 didn't significantly affect the structure of p6mm hexagonal symmetry [39]. The intensity of the (1 0 0) reflection decreases with the increase of tungsten species content, possibly owning to the change in electron density of tungsten incorporated materials, similar to XRD patterns of WO 3 -MCM-41 [35].…”

Section: Resultsmentioning

confidence: 94%

Synthesis, characterization, and visible-light-driven photocatalytic performance of W-SBA15

Chang

Wang

Luo

et al. 2016

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

a b s t r a c tA series of tungsten-containing mesoporous SBA15 with different tungsten contents were prepared through a direct co-condensation sol-gel method and then analyzed by various techniques. XRD patterns revealed that the original mesoporous morphology was maintained after introducing tungsten species and forms of tungsten species were changed from incorporated tungsten to isolated tungsten species or low oligomeric tungsten oxide species, and finally to crystalline WO 3 with the increase of tungsten precursor content, which were also proven by HRTEM images, UV-Vis DRS, and FT-IR spectra. The W-SBA15 samples exhibited satisfactory photocatalytic performance toward degradation of dye Rhodamine B (RhB) and 2,4-dichlorophenol (2,4-DCP). In particular, the best candidate, sample 10%W-SBA15 showed an apparent reaction rate constant for RhB that was nearly 10 times as high as that of bulk WO 3 . The enhancement of photocatalytic capability was attributed to the mesoporous morphology with enlarged surface areas, negatively charged surface, and favorable tungsten forms such as incorporated tungsten, isolated tungsten or low oligomeric tungsten oxide species. In addition, active radicals trapping experiments and DMPO spin-trapping ESR spectra indicated that photogenerated holes were major oxidative species during photocatalysis.

show abstract

Synthesis, characterization, and catalytic function of novel highly dispersed tungsten oxide catalysts on mesoporous silica

Cited by 132 publications

References 44 publications

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Investigating the Influence of Au Nanoparticles on Porous SiO₂–WO₃ and WO₃ Methanol Transformation Catalysts

Synthesis, characterization, and visible-light-driven photocatalytic performance of W-SBA15

Contact Info

Product

Resources

About

Synthesis, characterization, and catalytic function of novel highly dispersed tungsten oxide catalysts on mesoporous silica

Cited by 132 publications

References 44 publications

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

Investigating the Influence of Au Nanoparticles on Porous SiO2–WO3 and WO3 Methanol Transformation Catalysts

Synthesis, characterization, and visible-light-driven photocatalytic performance of W-SBA15

Contact Info

Product

Resources

About

Investigating the Influence of Au Nanoparticles on Porous SiO₂–WO₃ and WO₃ Methanol Transformation Catalysts