scholarly journals SEARCH FOR WAYS OF CONTROLLED MODIFICATION OF CHARACTERISTICS OF FUNCTIONAL UNITS OF ADAPTIVE AIR PURIFICATION SYSTEMS

2021 ◽  
pp. 34-51
Author(s):  
Oleksandr Dryuchko ◽  
Natalia Bunyakina ◽  
Bogdan Korobko ◽  
Oleksandr Shefer ◽  
Kateryna Kytaihora ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Alkali Metals ◽  
Cooperative Behavior ◽  
Air Purification ◽  
Structure Characteristic ◽  
Organic Substrates ◽  
Functional Dependencies ◽  
Coordination Polyhedra ◽  
Functional Units ◽  
Composition Structure

Information on alkaline coordination nitrates of rare-earth elements of the cerium subgroup - precursors of promising modern multifunctional materials - on the conditions of their formation and existence, the nature of the chemical bond, the composition, structure, shape of the Ln coordination polyhedra, the type of ligand coordination, and the existence of isotypic series in stoichiometry are generalized. composition, structure, characteristic properties. The data obtained (as primary information) is the basis for the detection, identification, and control of the phase state of processing objects in the preparatory stages, the choice of criteria for the compatibility of the components in the formation of single-layer and layered nanostructured oxide composite systems of lanthanides and transition elements for general purposes, with catalytic and photocatalytic activity, coatings self-cleaning with hydrophilic properties; development of various combined methods for their activation and identification of technological functional dependencies; controlled modification of the properties of the obtained target products. To increase the photocatalytic activity of coating samples based on highly dispersed anatase TiO2, a methodology for chemical modification of oxidation centers in their surface layer with heat treatment in contact with thermolysis products of alkaline coordination lanthanide nitrate melts is proposed. An effective test photocatalytic destruction of organic substrates vapors has been discovered using ethanol as an example.Effective activation of the functioning of functional units in the composition of self-adjusting air purification complexes using new photocatalytically active three-layer perovskite-like oxide materials M2Ln2Ti3O10 (M - Li, Na, K; Ln - La, Nd) has been proven. The variability of such methods for creating and modifying the characteristics of polyfunctional coatings is determined by the number and individual properties of representatives of the natural series of lanthanides, alkali metals of the periodic system, the peculiarities of their cooperative behavior in the preparatory technological stages, conditions and methods of activation of formation processes, the nature of the substrate, and other factors.

The effect of Ag, Au, Pt, and Pd on the surface properties, photocatalytic activity and toxicity of multicomponent TiO2-based nanomaterials

2020 ◽  
Vol 7 (11) ◽  
pp. 3557-3574
Author(s):  
Anna Malankowska ◽  
Alicja Mikołajczyk ◽  
Joanna Mędrzycka ◽  
Izabela Wysocka ◽  
Grzegorz Nowaczyk ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Surface Properties ◽  
Rational Design ◽  
Photocatalytic Properties ◽  
Air Purification ◽  
Component Concentration

A better understanding how to the component concentration, photocatalytic properties and toxicity of multicomponent TiO2-based nanomaterials (NMs) may lead to rational design of new and safe NMs with wide application in air purification.

Preparation of Bi1-xLaxVO4 and its Photocatalytic Degradation on Rhodamine B

2016 ◽  
Vol 852 ◽  
pp. 1473-1476
Author(s):  
Yan Ding ◽  
Liang Fang Fu ◽  
Yu Huan Wang ◽  
Liang Chao Li ◽  
Juan Bi Li
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Degradation Rate ◽  
Light Sensitivity ◽  
Structure Morphology ◽  
Photocatalytic Activities ◽  
Testing Techniques ◽  
Composition Structure

A series of photocatalyst Bi1-xLaxVO4 (0.1, 0.3, 0.5, 0.7) powders were prepared by hydrothermal method. The composition, structure, morphology and photocatalytic activity of the samples were researched by means of modern testing techniques. Bi1-xLaxVO4 showed excellent visible-light sensitivity and photocatalytic activities. The degradation rate of sample with x = 0.5 on rhodamine B reached 90 %, which was much higher than that of pure BiVO4.

Hydrothermal Synthesis of Visible Light Active SnO2-SnS2 Nanocomposite Photocatalyst for the Reduction of Cr(VI) in Water

2013 ◽  
Vol 709 ◽  
pp. 7-10
Author(s):  
Jing Li ◽  
Xi Hua Du ◽  
Wei Min Dai ◽  
Yong Cai Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Sno2 Nanoparticles ◽  
High Photocatalytic Activity ◽  
X Ray ◽  
Transmission Electron ◽  
Visible Light Active ◽  
Composition Structure

A low temperature (130 °C) hydrothermal method was proposed for the synthesis of SnO2-SnS2 nanocomposite. The composition, structure and optical property of the as-synthesized SnO2-SnS2 nanocomposite were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectra, and its photocatalytic activity was tested by the reduction of Cr(VI) in water under visible light (λ > 420 nm) irradiation. It was found that the as-synthesized SnO2-SnS2 nanocomposite exhibited high photocatalytic activity in the reduction of Cr(VI) in water under visible light (λ > 420 nm) irradiation, whereas SnO2 nanoparticles displayed no photocatalytic activity in the reduction of Cr(VI) in water under visible light (λ > 420 nm) irradiation.

Preparation and Photocatalytic Properties of Magnetic TiO2 Compounds

2011 ◽  
Vol 396-398 ◽  
pp. 306-310
Author(s):  
Li Jun Yan ◽  
Yue Cheng ◽  
Xiao Juan Yan ◽  
Tan Tan Ge
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Intermediate Layer ◽  
Uv Light ◽  
Sol Gel ◽  
Middle Layer ◽  
Negative Influence ◽  
Magnetic Composite ◽  
Composite Photocatalysts ◽  
Composition Structure

In this paper, magnetic composite photocatalysts were prepared through depositing TiO2 on the surface of NiFe2O4 by sol-gel method. The composition, structure and magnetism of the samples are tested by XRD, TEM and VSM, respectively. The photoactivity of the as-prepared photocatalysts was investigated by degrading methyl orange under UV light. The effect of NiFe2O4 and SiO2 intermediate layer on the activity of photocatalyst was also studied. It has been found that NiFe2O4 has a negative influence on the photocatalytic activity of magnetic TiO2 compounds. The middle layer of SiO2 can effectively improve the photocatalytic activity of magnetic TiO2 compounds.

scholarly journals Enhanced Visible Light Active WO3 Thin Films Toward Air Purification: Effect of the Synthesis Conditions

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3506
Author(s):  
Anna Pancielejko ◽  
Marta Rzepnikowska ◽  
Adriana Zaleska-Medynska ◽  
Justyna Łuczak ◽  
Paweł Mazierski
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Air Pollutant ◽  
Air Purification ◽  
Photocurrent Response ◽  
Ambient Conditions ◽  
Photocatalytic Ability ◽  
Synthesis Conditions ◽  
Electrochemical Approach ◽  
Wo3 Thin Films

Taking our current environmental situation in the world into consideration, people should face growing problems of air and water pollution. Heterogeneous photocatalysis is a highly promising tool to improve both air and water quality through decomposition/mineralization of contaminants directly into harmless CO2 and H2O under ambient conditions. In this contribution, we focused on the synthesis of self-assembly WO3 thin films via an electrochemical approach in the aqueous electrolyte containing fluoride ions toward air purification. The effect of preparation conditions such as applied potential (10–50 V), anodization time (15–120 min), concentration of H2SO4 (0.5–1.5 M) and NaF (0.1–1.0 wt.%) on the morphology, photocurrent response, and photocatalytic activity addressed to removal of air pollutant in the presence of as-prepared WO3 samples were thoroughly examined and presented. The results revealed the growth of nanoplatelets and their gradual transformation into flower-like structures. The oxide layers and platelet thickness of the WO3 samples were found to be proportionally related with the synthesis conditions. The photocatalytic ability toward air purification was evaluated by degradation of toluene from air mixture using low-powered LEDs as an irradiation source (λmax = 415 nm). The highest photoactivity was achieved in presence of the sample which possessed a well-ordered, regular shape and repeatable distribution of flower buds (100% of degradation). The results have confirmed that the oxide layer thickness of the anodic WO3 significantly affected the photocatalytic activity, which increased with the increasing thickness of WO3 (to 1.05 μm) and then had a downward trend. The photocurrent response evidenced that the well-organized sample had the highest ability in photocurrent generation under UV-Vis and Vis irradiation. Finally, a possible growth mechanism of WO3 NFs was also discussed.

In situ Synthesis of p–n LaFeO3/ZnIn2S4 Heterojunctions for Enhanced Photocatalytic Activity

NANO ◽  
2019 ◽  
Vol 14 (08) ◽  
pp. 1950096 ◽  
Author(s):  
Wen Gao ◽  
Chengjia Zhang ◽  
Sainan Cui ◽  
Qian Liang ◽  
Song Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
In Situ Synthesis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ft Ir ◽  
Composition Structure

In this study, LaFeO3/ZnIn2S4 composites were synthesized via in situ synthesis. The composition, structure and optical absorption properties of LaFeO3/ZnIn2S4 were characterized by X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy, fluorescence spectroscopy (PL), Fourier Transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The photocatalytic activity of the LaFeO3/ZnIn2S4 photocatalyst was determined based on the degradation of methyl orange (MO). LaFeO3/ZnIn2S4 composites showed much better photocatalytic performance compared with pure LaFeO3 and ZnIn2S4. The enhanced photocatalytic performance was attributed to intimately contacted interfaces and charge transfer channels which can effectively transfer and separate the photogenerated charge carriers.

scholarly journals Fast Method for Testing the Photocatalytic Performance of Modified Gypsum

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 693 ◽  
Author(s):  
Janus ◽  
Zając ◽  
Ehm ◽  
Stephan
Keyword(s):  
Photocatalytic Activity ◽  
Building Materials ◽  
Photocatalytic Performance ◽  
Air Purification ◽  
Fast Method ◽  
Angle Measurements ◽  
Activity Measurements ◽  
Contact Angle Measurements ◽  
Different Types

The measurement of the photocatalytic activity of building materials is quite time-consuming. Up until now, researchers have mainly used the equipment described in ISO 22197-1 to ISO 22197-4 for the determination of air purification activity, although other apparatus such as colorimeters, UV-Vis/DR spectroscopes and equipment for contact angle measurements have also been used. Usually, photocatalytic activity measurements take from one hour up to several hours. In this study, we present a very fast method for the measurement of the photocatalytic activity of gypsum. A specially designed printer with a modified bubblejet cartridge was used to apply a special ink on the surface of gypsum plates. Then the surface was irradiated by UV-A light and every 3 s a picture of the surface was taken. The results showed that the discoloration of the dye occurs after a few seconds of irradiation and the time depends on the amount of photocatalyst used as well as the number of printed ink layers. It was concluded that it is possible to use this method for a quick comparison of the photocatalytic activity of different types of modified gypsum materials.

Alkali metals incorporated ordered mesoporous tantalum oxide with enhanced photocatalytic activity for water splitting

2016 ◽  
Vol 4 (8) ◽  
pp. 3007-3017 ◽  
Author(s):  
Tobias Grewe ◽  
Harun Tüysüz
Keyword(s):  
Photocatalytic Activity ◽  
Water Splitting ◽  
Alkali Metals ◽  
Tantalum Oxide ◽  
Photocatalytic Water Splitting ◽  
Alkali Earth ◽  
Ordered Mesoporous ◽  
Soft Templating ◽  
Templating Synthesis

We present a soft-templating synthesis of amorphous ordered mesoporous tantalates with incorporated alkali earth metals for photocatalytic water splitting.

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