Search query: Novel photocatalytic coatings based on tin oxide semiconductor

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abstract: ABSTRACT In this research, pure SnO2 was deposited on 316 stainless steel plates using air plasma spraying. Micrograph and phase composition of the deposited films were studied using SEM and X ray diffraction, respectively; and methylene blue solution was used to evaluate the activity of the deposited photocatalytic coatings. It was shown that air plasma spraying could be used as an efficient method to deposit pure SnO2 photocatalytic coatings. UV vis diffuse reflectance spectra analysis showed higher photo absorption ability of the deposited films as compared to the initial powder. Although all the tin oxide coatings had lower band gap energy than the initial powder, further studies are needed to deposit SnO2 films, which can act as photocatalytic coatings under visible light irradiation. Comparison of the photocatalytic activity of tin oxide coatings with that of ZnO film showed the adequate activity of tin oxide coatings deposited by air plasma spraying.
author_names: Amir Hossein Navidpour

Mohammad Bagher Fakhrzad

Mostafa Tahari

Sedigheh Abbasi
title: Novel photocatalytic coatings based on tin oxide semiconductor
year: 2019

abstract: Titanium dioxide based photocatalysts have some major drawbacks that cannot be overcome at present. Firstly, the photocatalytic reaction rates are typically very low, which makes this technology not appropriate for high throughput processes, such as detoxification of highly polluted industrial waste or disinfection of heavily soiled surfaces. Secondly, only UV light can be utilized for activation of titania based materials, which is less than 5% of solar spectrum. Therefore, there is an obvious need for development of novel efficient low band gap semiconductors that can be activated using visible light and thus provide an effective, environmentally friendly solution for water treatment. Magnetron sputtering is a simple and versatile method used for the deposition of thin films, readily scalable and widely used in both laboratories and industrial production facilities, including production of photocatalytic coatings. In the present work several narrow band gap semiconductor coatings have been produced by pulsed DC magnetron sputtering and studied as potential alternatives to TiO 2 based photocatalysts. Thin films of bismuth complex oxides (molybdate and tungstate) tantalum oxynitride and nitride and cerium dioxide have been deposited onto variety of substrates and analysed by a range of methods, including SEM/EDX, XRD, TEM, XPS and Raman spectroscopy. The photocatalytic properties of the coatings were studied both under UV and visible light sources using dye degradation tests. The results of the photocatalytic tests were compared to a commercially available photocatalytic material. The results of the study revealed that, with optimised deposition conditions, the narrow band gap semiconductors studied have potential as alternatives to traditional TiO 2 based photocatalysts, demonstrating visible light activity superior to a sample of commercial photocatayst. The influence of deposition conditions and post deposition processing on photocatalytic properties are also discussed.
author_names: Marina Ratova

Peter J Kelly

G T West
title: Deposition of narrow band semiconductor coatings by pulsed DC magnetron sputtering for visible light photocatalysis applications
year: 2016

abstract: Thin film technology for device applications are based on material structures created by thin film deposition and characterization [1] In recent time, there are growing demands for more efficient solar cell technology and also electronic devices that could operate at high power levels. Suitable thin films for these applications require wide band gap, high optical conductivity, high transparency and stability at higher temperature [2] The numerous varieties of electronic, optical and solid state properties of metal oxides make them suitable materials for basic research that results in invention of novel systems and improvement on the exiting. Oxides have a wide range of properties from wide band gap insulators, metallic to superconducting. Tin oxide belongs to a class of materials called Transparent Conducting Oxides (TCO) constituting an important component for optoelectronic applications [3] Tin oxide thin films have some useful applications in visible light and infrared light. It has low electrical sheet resistance, rendering it suitable for a wide variety of applications as gas sensors, electrodes in solar cells, infrared reflectors for glass windows, transparent electrodes in electroluminescent lamps and displays [4, 5] Other useful properties are high mechanical hardness and good environmental stability. Tin Oxide (SnO2) is a n type semiconductor with wide energy band gap (3.7 eV) [6] The methodology employed for thin film deposition ranges from very simple and cheap to complex and very expensive depending on the substrate type, material to be deposited and the required performance of the films [7] In this work, the spin coating deposition which is a simple, quick and relatively cost effective technique was adopted. UVVis spectrophotometer and scanning electron microscopy are used to characterize the spin coated SnO2 film grown on glass substrates at room temperature. Abstract: This work consists of the preparation of thin film of tin oxide using automated spin coating technique. Investigations of the surface morphology and optical characteristics of the deposited films were examined. Thin film of tin oxide (SnO2) is a special class of transparent metal oxides that combine high optical conductivity with high transparency. Such Transparent Conducting Oxide (TCO) provides an important component for optoelectronic applications. The transmittance and reflectance spectra were obtained with a UVVis spectrophotometer while the microphotograph was obtained using a scanning electron microscope. The thin film produced has high transparency, wide band gap and low dielectric constant. Optical characterization was done over a range of wavelength of 250 nm to 1000 nm which corresponds to photon energy between 1.2 eV to 5.0 eV. The average transmittance is 85 average optical conductivity is 0.032 x 10 16 S 1 average extinction coefficient is 1.25, average real dielectric constant is 7.5 and the band gap energy is estimated to be 3.78 eV. The SEM micrograph of the SnO2 film shows the existence of some agglomerates of small rounded particles. Tin oxide thin films have a number of applications such as in optical coatings, high temperature superconductivity and communication, solar cell fabrication especially as an absorption layer and a transparent contact.
author_names: Sunday Samuel Oluyamo
title: Spin Coated Tin Oxide Thin Film For Optical And Optoelectronic Material Applications
year: 2016

abstract: Photocatalysis is a potential technology for removing pollutants from water. As the recombination of the photogenerated electron hole pairs can hinder the photocatalytic efficiency in the treatment of wastewater, the surface of the carrier is usually coated with a semiconductor. In this study, carbon microtube electrode prepared from corncob was coated with either titanium oxide (TiO2) or bismuth phosphate (BiPO4) and then used as a photocatalyst (C TiO2 or C BiPO4) to investigate the photodegradation of methylene blue (MB) The two photocatalysts, C TiO2 and C BiPO4, were characterized by phase determination, microstructure observation, water contact angle measurement, and base site analysis. The influences of reaction time, stability, MB concentration, initial pH, and OH radicals quenching on the degradation of MB were also evaluated. The degradation of MB by C TiO2 and C BiPO4 was mainly dominated by OH radical oxidation. The carbon microtube increased both the mass transfer rate and the photogenerated electron hole pairs separation rate, thereby increasing the photocatalysis of both C TiO2 and C BiPO4 as revealed by an increase in the rate of MB degradation. The rate constants obtained for the degradation of MB by C TiO2 and C BiPO4 at 20 degC were 9.739 x 10 7 mM min 1 and 1.111 x 10 7 mM min 1, respectively. The coating of TiO2 and BiPO4 on the surface of the carbon microtube electrode enhanced their photocatalytic performance, and therefore, C TiO2 and C BiPO4 could be developed into a novel material to be used in the photodegradation of dye pollutants.
author_names: Tian Xia

Zengling Ma

Manqing Ai

Kairong Qian

Shunan Zhu

Mengwei Rong

Pingping Zhang

Ying Ye

Wenli Qin
title: Photocatalyst coated carbon microtube electrodes: Preparation and characterization of their properties and photocatalytic degradation of methylene blue.
venue: Chemosphere
year: 2020

abstract: Surface temperature measurements of ceramic matrix composite (CMC) based engine components within the hot section of a gas turbine engines are needed to verify engine designs and cooling requirements. Traditional temperature sensors cannot be applied to silicon carbide (SiC) based CMC's for this purpose, since they cannot be welded or embedded in the material. For these reasons, a novel thermocouple was developed for surface temperature measurement of p type SiC SiC CMC's. This novel thermocouple uses the p type SiC SiC CMC itself as one of the thermoelements and indium tin oxide (ITO) as the other thermoelement. Since both thermoelements are wide bandgap semiconductors, this thermocouple has exceptional thermoelectric output. A thermoelectric output of 272 mV/degK was observed for this ITO:SiC CMC thermocouple, which is an order of magnitude larger than that of type K thermocouples. A drift rate of 3.28 degC/h was measured for this ITO:SiC CMC thermocouple. In addition, indium tin oxynitride (ITON) protective coatings deposited via reactive sputtering enabled these thermocouples to operate at 1000 degC. The ITON coating served as an oxygen diffusion barrier to prevent oxidation at the ITO:SiC CMC junction. Nitrogen and air anneals at 550 and 1000 degC, respectively, were used to improve the high temperature stability of the ITO and ITON coatings. Performance, fabrication details, and challenges using these ITO:SiC CMC thermocouple are discussed within.
author_names: Kevin Rivera

Otto J Gregory
title: ITO:SiC Ceramic Matrix Composite Thermocouples for Engine Components
venue: IEEE Sensors Letters
year: 2020

abstract: Abstract Cupric oxide (CuO) is a semiconductor of choice for photocathode in photoelectrochemical (PEC) applications due to its great sunlight absorption capability. However, photocorrosion is the main drawback of CuO. Herein, CuO/graphitic carbon nitride (g C3N4) with a unique microstructure, enhanced PEC performance, and considerable photostability is synthesized under microwave irradiation. A facile, one pot method is utilized to directly deposit the nanocomposite onto fluorine doped tin oxide from a solution containing copper precursor and urea. Possible mechanism of CuO/g C3N4 formation through this novel method is investigated. It is elucidated that controlled amounts of urea critically determine the morphological evolution of CuO, while its excess quantities convert to g C3N4 in the presence of CuO as the catalyst. Through an appropriate heat treatment, carbon is doped into CuO lattice. The obtained C doped CuO/g C3N4 demonstrates 227% enhancement over CuO in photocurrent density and ~80% photocurrent retention. The enhanced photoelectrocatalytic activity is mainly attributed to unique morphology of CuO, effective separation of charge carriers, and formation of heterojunction. These characteristics manifest the superiority of this approach over many other chemical based methods. The nanocomposite synergistically integrates the advantages of both the constituents, offering a low cost, efficient photocathode for PEC water splitting, photocatalytic hydrogen evolution, and degradation of pollutants.
author_names: Seyed Morteza Hosseini H

Roozbeh Siavash Moakhar

Foad Soleimani

Sayed Khatiboleslam Sadrnezhaad

Saeid Masudy-Panah

Reza Katal

Ashkan Seza

Navid Ghane

Seeram Ramakrishna
title: One pot microwave synthesis of hierarchical C doped CuO dandelions/g C3N4 nanocomposite with enhanced photostability for photoelectrochemical water splitting
year: 2020

abstract: Abstract The microstructure, optical and electrical properties of CrAlN and (Cr, Al) films synthesized by DC reactive magnetron sputtering method have been comparatively investigated. The results show that CrAlN film crystallizes in B1 NaCl typed CrN structure with the preferred growth orientations of (1 1 1) and (2 2 0) and CrAlN grains show perfectly crystalline pyramid like shape. The CrAlN film is determined as Al doped CrN phase with the chemical formula of Cr 0.9136 Al 0.0864 N 0.8999 It shows similar reflectance and absorptance characteristics to those of TiN based films in the solar spectrum region (300 2600 nm) and exhibits semiconductor nature with a sheet resistance of 38 kO/sq. Hence CrAlN can be used as a novel candidate material for high temperature solar selective absorber coatings with good thermal stability and oxidation resistance.
author_names: Jianlin Chen

Chen Guo

Jian Chen

Jian-jun He

Yanjie Ren

Hu Linlin
title: Microstructure, optical and electrical properties of CrAlN film as a novel material for high temperature solar selective absorber applications
year: 2014

abstract: The ability to control the position and orientation of nanorods in a device is interesting both from a scientific and a technological point of view. Because semiconductor nanorods exhibit anisotropic absorption, and spontaneous and stimulated emission, aligning individual NRs to a preferred axis is attractive for many applications in photonics such as solar cells, light emitting devices, optical sensors, switches, etc. Electric field driven deposition from colloidal suspensions has proven to be an efficient method for the controlled positioning and alignment of anisotropic particles. In this work, we present a novel technique for the homogeneous deposition and alignment of CdSe/CdS NRs on a glass substrate patterned with transparent indium tin oxide interdigitated electrodes, with a spacing of a few micrometers. This method is based on applying a strong AC electric field over the electrodes during a dip coating procedure and subsequent evaporation of the solvent. The reproducible and homogeneous deposition on large substrates is required for large size applications such as solar cells or OLEDs. The accumulation, alignment, and polarized fluorescence of the nanorods as a function of the electrical field during deposition are investigated. A preferential alignment with an order parameter of 0.92 has been achieved.
author_names: Mohammad Mohammadimasoudi

Lieven Penninck

Tangi Aubert

Raquel Gomes

Zeger Hens

Filip Strubbe

Kristiaan Neyts
title: Polarized light emission by deposition of aligned semiconductor nanorods
venue: Optics Photonics NanoScience Engineering
year: 2014

abstract: In this paper, we present a highly efficient SnS nanoparticle sensitized zinc oxide (ZnO) nanorod based photocatalyst, which can degrade strong organic dyes under direct exposure to sunlight. The thermal decomposition technique was adopted to prepare crystalline ZnO nanorods, which were subsequently sensitized with a narrow bandgap semiconductor, namely tin sulfide (SnS) via in situ and ex situ sensitization processes. Here, SnS acts as a photosensitizer to expand the light absorption range from the UV VIS NIR spectral region. In addition, the formation of the SnS/ZnO heterostructure suppresses the electron hole pair recombination via the formation of a p n heterojunction and enhances the separation of photoexcited charge carriers. Thereafter, the photocatalytic activity of the pristine ZnO nanorods and sensitized SnS/ZnO nanorods was investigated in the degradation of three different strong dyes under sunlight illumination. It was observed that the in situ sensitization process helps in achieving a uniform coating of SnS over the surface of the ZnO nanorods, which resulted in an enhanced photocatalytic performance in dye degradation in comparison to the ex situ sensitized SnS/ZnO nanorods and pristine ZnO nanorods. The rate constants for the in situ sensitized SnS/ZnO nanorods determined from experimental data were found to be 0.0245 min 1, 0.0212 min 1 and 0.0139 min 1 in the photodegradation of Rhodamine 6G, Rhodamine B, and Methyl Orange dyes, respectively. Thus, we can infer from our experimental results that the in situ sensitized SnS/ZnO nanorods could be an economical and promising inorganic photocatalytic material, in addition to the TiO2 photocatalyst for photodegradation of toxic organic dyes present in water.
author_names: Shefali Jayswal

Rakesh S Moirangthem
title: Construction of a solar spectrum active SnS/ZnO p n heterojunction as a highly efficient photocatalyst: the effect of the sensitization process on its performance
year: 2018

abstract: TiO2 nanotube semiconductors contain free spaces in their interior that can be filled with active materials such as chemical compounds, enzymes, and noble metals, giving them a fundamental advantage over colloids. Although the unique shape of semiconductor nanotubes makes them promising for a range of potential applications, significant developmental research is required. In this research, a novel TiO2 nanotube photocatalyst was prepared that has a p n junction. The photocatalyst particle surface is physically divided into reduction and oxidation surfaces, which poses a potential driving force for the transport of photogenerated charge carriers. The structure of this nanotube catalyst was characterized using a scanning electron microscope (SEM) and X ray diffraction (XRD) The catalyst activity was evaluated by coating the catalyst on HEPA filters and determining the destruction rate of toluene in air. The p n junction nanotube catalyst was shown to have a much higher photocatalytic destruction rate than that of commercially available, nonnanotube structured material, and a higher destruction rate for nanotube catalysts that did not contain a p n junction.
author_names: Yongsheng Chen

John C Crittenden

Stephen A Hackney

Lawrence L Sutter

David W Hand
title: Preparation of a novel TiO2 based p n junction nanotube photocatalyst.
venue: Environmental science technology
year: 2005