Synthesis and Application of Fe-Doped WO3 Nanoparticles for Photocatalytic Degradation of Methylparaben Using Visible–Light Radiation and H2O2

Ngigi, Eric M.; Nomngongo, Philiswa N.; Ngila, Jane Catherine

doi:10.1007/s10562-018-2594-y

Cited by 19 publications

(2 citation statements)

References 68 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consequently, di-modified WO 3 samples showed high photocatalytic activity compared to bare WO 3 . This assisted Fenton process was also described by Mwangl Ngigi et al [414] for photocatalytic degradation of Methylparaben (MeP) over Fe-doped WO 3 nanoparticles in presence of H 2 O 2 . The best formulation was 5 wt.% Fe-WO 3, with 50.8% MeP degradation in the presence of H 2 O 2 .…”

Section: Zno-womentioning

confidence: 58%

Tungsten-Based Catalysts for Environmental Applications

2021

View full text Add to dashboard Cite

This review aims to give a general overview of the recent use of tungsten-based catalysts for wide environmental applications, with first some useful background information about tungsten oxides. Tungsten oxide materials exhibit suitable behaviors for surface reactions and catalysis such as acidic properties (mainly Brønsted sites), redox and adsorption properties (due to the presence of oxygen vacancies) and a photostimulation response under visible light (2.6–2.8 eV bandgap). Depending on the operating condition of the catalytic process, each of these behaviors is tunable by controlling structure and morphology (e.g., nanoplates, nanosheets, nanorods, nanowires, nanomesh, microflowers, hollow nanospheres) and/or interactions with other compounds such as conductors (carbon), semiconductors or other oxides (e.g., TiO2) and precious metals. WOx particles can be also dispersed on high specific surface area supports. Based on these behaviors, WO3-based catalysts were developed for numerous environmental applications. This review is divided into five main parts: structure of tungsten-based catalysts, acidity of supported tungsten oxide catalysts, WO3 catalysts for DeNOx applications, total oxidation of volatile organic compounds in gas phase and gas sensors and pollutant remediation in liquid phase (photocatalysis).

show abstract

Section: Zno-womentioning

confidence: 58%

Tungsten-Based Catalysts for Environmental Applications

2021

View full text Add to dashboard Cite

show abstract

“…In the case of lighter single atoms and heavy metal oxide supports (e.g., Fe@WO 3 ), HAADF-STEM imaging may possibly work if the iron single atom substitutes into the tungsten site. [54,55] With a sufficiently thin region, the substituted site can have a noticeable decrease in intensity, signaling the substitution of the lighter element single atom into the lattice (at the surface or in the bulk). However, this analysis method requires the sampled region to have a consistent local thickness.…”

Section: Atomic Visualization Of Distinct Elementsmentioning

confidence: 99%

Directly Probing the Local Coordination, Charge State, and Stability of Single Atom Catalysts by Advanced Electron Microscopy: A Review

Tieu

Yan

et al. 2021

Small

View full text Add to dashboard Cite

of a heterogeneous catalyst. Any atom not at the catalyst surface is not directly used to drive chemical conversions, which is a critical consideration for the use of precious metal catalysts. To that end, the use of smaller particles with high surface/ volume ratios has been the preferred choice to maximize metal utilization. Recent advancements in the synthesis of nanomaterials with targeted shapes and sizes have resulted in the production of catalysts with designed catalytic properties. Single atom catalysts (SACs) have furthered the field of catalysis due to the potential for carefully controlled active site properties and distinct capabilities compared to bulk and nanoparticle catalysts. The reduction in size of the metal modifies the behavior through several mechanisms including: quantum size effect, [1][2][3][4] strong metal-support interactions (SMSI), [5][6][7] surface effects, [8][9][10][11] and varied oxidation states. [12] As a result of these influences, the coordination environment of single atoms on supports control their reactivity.Visualizing SACs is important to understand the formation, coordination environment, and stability of the catalyst. Oftentimes, bulk and nanoparticle catalysts release atoms during a catalytic process, which may contribute to the measured catalytic activity and changes in activity as a function of time. Recent work visualizing the release of Au single atoms, from nanoporous Au surfaces during methane pyrolysis, demonstrates the importance of visualizing catalysts at the atomic scaleThe drive for atom efficient catalysts with carefully controlled properties has motivated the development of single atom catalysts (SACs), aided by a variety of synthetic methods, characterization techniques, and computational modeling. The distinct capabilities of SACs for oxidation, hydrogenation, and electrocatalytic reactions have led to the optimization of activity and selectivity through composition variation. However, characterization methods such as infrared and X-ray spectroscopy are incapable of direct observations at atomic scale. Advances in transmission electron microscopy (TEM) including aberration correction, monochromators, environmental TEM, and microelectro-mechanical system based in situ holders have improved catalysis study, allowing researchers to peer into regimes previously unavailable, observing critical structural and chemical information at atomic scale. This review presents recent development and applications of TEM techniques to garner information about the location, bonding characteristics, homogeneity, and stability of SACs. Aberration corrected TEM imaging routinely achieves sub-Ångstrom resolution to reveal the atomic structure of materials. TEM spectroscopy provides complementary information about local composition, chemical bonding, electronic properties, and atomic/molecular vibration with superior spatial resolution. In situ/operando TEM directly observe the evolution of SACs under reaction conditions. This review concludes with remarks on the challenges an...

show abstract