Polymer-coating of photocatalytic particles to prevent sintering in their calcination process

Namigata, Hikaru; Watanabe, Kanako; Okubo, Saya; Nagao, Daisuke

doi:10.1016/j.colsurfa.2020.124782

Cited by 8 publications

(7 citation statements)

References 34 publications

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“…Submicron-sized amorphous TiO 2 cores were prepared via a sol-gel method, with a solvent containing ethanol and acetonitrile [35]. The TiO 2 cores were coated with polystyrene (PSt), similar to our previous reports (Figure 1b) [36,37]. The shell thickness of the PSt formed on the cores ranged from 140 to 330 nm.…”

Section: Fabrication Of the Dio Photocatalytic Assemblymentioning

confidence: 94%

“…(Osaka, Japan), C018001), which had been hydrophilized with a UV ozone cleaner (Filgen, Aichi, Japan, UV253E) for 30 min. After the dispersion medium of the mixture was evaporated, the particle assembly was calcined for 2 h at 500 • C. Notably, the TiO 2 particles of the assemblies could be crystallized into the anatase phase via heat treatment at 500 • C [37,38].…”

Section: Fabrication Of the Dio Photocatalytic Assemblymentioning

confidence: 99%

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Double-Inverse-Opal-Structured Particle Assembly as a Novel Immobilized Photocatalytic Material

et al. 2020

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Immobilization of photocatalysts on supports is an important method of adding highly active photocatalysts to a continuous flowing system without the need for photocatalyst recovery. However, direct immobilization prevents exposure to all photocatalytically active surfaces. Therefore, to immobilize particulate photocatalysts, while exposing the photocatalytic surface to organic pollutant water in a continuous flowing system, in this study, we employed double-inverse-opal (DIO) with periodically arranged, interconnected macropores, each containing a single photocatalytic particle. Increasing the macropore size successfully enhanced the decomposition rate of organic dye due to the high diffusion rate of dye molecules in the macropores of thin DIOs. However, an excessive increase in macropore size lowered the decomposition rate of dye molecules because an increase in DIO thickness caused the attenuation of light used to excite the photocatalytic particles. This study presents novel, immobilized photocatalytic DIO-structured particles that can be employed in continuous flowing reaction systems by tuning the photocatalytic particle size, macropore size, and DIO thickness.

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Section: Fabrication Of the Dio Photocatalytic Assemblymentioning

confidence: 94%

Section: Fabrication Of the Dio Photocatalytic Assemblymentioning

confidence: 99%

Double-Inverse-Opal-Structured Particle Assembly as a Novel Immobilized Photocatalytic Material

et al. 2020

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“…The details of each procedure and synthesized particles are presented in the Supporting Information. The heat treatment also promotes the crystallization of TiO 2 from the amorphous to anatase phase, which increases the refractive index. Because the core particles were stuck on the inner wall of silica shells after the heat treatment, the inner silica shell walls were dissolved slightly in NH 3 aq (pH ∼11).…”

Section: Methodsmentioning

confidence: 99%

Switchable Bragg Reflections via Controllable Inner Particle Motion in Yolk–Shell Colloidal Crystals

Namigata,

Welling,

Watanabe

et al. 2023

ACS Appl. Opt. Mater.

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Yolk−shell particles consist of a hollow shell enclosing a mobile inner particle. Colloidal crystals made from yolk−shell particles are a unique structure, in which the disorder of highly scattering inner particles can be controlled, which allows for optical switching. In this work, yolk−shell particles were synthesized and assembled into an ordered structure. External alternating current (AC) electric fields were used to control the inner particle motion, as observed by confocal microscopy and optical reflection measurements. The colloidal crystal of yolk−shell particles showed long-range order due to the assembled shells but decreased short-range order due to the Brownian motion of inner particles. Using an AC electric field (25 V/mm), all inner particles moved electrophoretically, resulting in ordered inner-particle arrangements. This enabled the fast, reversible switching of the Bragg reflection intensities. Next, we investigated how a decreased short-range order when the field is off influenced the switchability. The largest optical intensity change was achieved with a high ionic strength (10 mM) and a small coreto-shell size ratio (∼0.3). Our proof-of-concept results show promise that with further optimization, even more strongly switchable photonic crystals can be achieved in this way.

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“…The PVA/TiO 2 mass ratio and the heat treatment temperature are the major controlling factors for generating composites of the correct porosity [59]. Studies show that coating photocatalysts like TiO 2 with a sacrificial layer of polymeric material can prevent sintering of the catalyst particles during the calcination processes and retain the crystallinity of the photocatalyst without decreasing the specific surface area [60]. The photocatalytic activities of TiO 2 essentially depend greatly on the degree of crystallization determining the percentage of anatase and rutile in the catalyst and also on the dispersibility in water.…”

Section: Preparation Of Polymer-coated Photocatalystsmentioning

confidence: 99%

Polymer Coated Functional Catalysts for Industrial Applications

Arya

Thapliyal

Pandit³

et al. 2023

Polymers

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Surface engineering of conventional catalysts using polymeric coating has been extensively explored for producing hybrid catalytic material with enhanced activity, high mechanical and thermal stability, enhanced productivity, and selectivity of the desired product. The present review discusses in detail the state-of-the-art knowledge on surface modification of catalysts, namely photocatalysts, electrocatalysts, catalysts for photoelectrochemical reactions, and catalysts for other types of reactions, such as hydrodesulfurization, carbon dioxide cycloaddition, and noble metal-catalyzed oxidation/reduction reactions. The various techniques employed for the polymer coating of catalysts are discussed and the role of polymers in enhancing the catalytic activity is critically analyzed. The review further discusses the applications of biodegradable and biocompatible natural polysaccharide-based polymers, namely, chitosan and polydopamine as prospective coating material.

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Polymer-coating of photocatalytic particles to prevent sintering in their calcination process

Cited by 8 publications

References 34 publications

Double-Inverse-Opal-Structured Particle Assembly as a Novel Immobilized Photocatalytic Material

Double-Inverse-Opal-Structured Particle Assembly as a Novel Immobilized Photocatalytic Material

Switchable Bragg Reflections via Controllable Inner Particle Motion in Yolk–Shell Colloidal Crystals

Polymer Coated Functional Catalysts for Industrial Applications

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