Effect of external bias voltage and coating thickness on the photocatalytic activity of thermal sprayed TiO2 coating

AbstractIncreasing demand for self-powered wearable sensors has spurred an urgent need to develop energy harvesting systems that can reliably and sufficiently power these devices. Within the last decade, reverse electrowetting-on-dielectric (REWOD)-based mechanical motion energy harvesting has been developed, where an electrolyte is modulated (repeatedly squeezed) between two dissimilar electrodes under an externally applied mechanical force to generate an AC current. In this work, we explored various combinations of electrolyte concentrations, dielectrics, and dielectric thicknesses to generate maximum output power employing REWOD energy harvester. With the objective of implementing a fully self-powered wearable sensor, a “zero applied-bias-voltage” approach was adopted. Three different concentrations of sodium chloride aqueous solutions (NaCl-0.1 M, NaCl-0.5 M, and NaCl-1.0 M) were used as electrolytes. Likewise, electrodes were fabricated with three different dielectric thicknesses (100 nm, 150 nm, and 200 nm) of Al2O3 and SiO2 with an additional layer of CYTOP for surface hydrophobicity. The REWOD energy harvester and its electrode–electrolyte layers were modeled using lumped components that include a resistor, a capacitor, and a current source representing the harvester. Without using any external bias voltage, AC current generation with a power density of 53.3 nW/cm2 was demonstrated at an external excitation frequency of 3 Hz with an optimal external load. The experimental results were analytically verified using the derived theoretical model. Superior performance of the harvester in terms of the figure-of-merit comparing previously reported works is demonstrated. The novelty of this work lies in the combination of an analytical modeling method and experimental validation that together can be used to increase the REWOD harvested power extensively without requiring any external bias voltage.

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Multi-Parameter Optimization to Improve the Erosion Resistance of Coating by Fe Simulation

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4053192 ◽

2021 ◽

Author(s):

Fang Li ◽

Liuxi Cai ◽

Shun-sen Wang ◽

Zhenping Feng

Keyword(s):

Tensile Stress ◽

Young’S Modulus ◽

Impact Velocity ◽

Coating Thickness ◽

Poisson’S Ratio ◽

Erosion Resistance ◽

Young's Modulus ◽

Tio2 Coating ◽

Poisson's Ratio ◽

Stress Peak

Abstract Finite element method (FEM) was used to study the stress peak of stress S11 (Radial stress component in X-axis) on the steam turbine blade surface of four typical erosion-resistant coatings (Fe2B, CrN, Cr3C2-NiCr and Al2O3-13%TiO2). The effect of four parameters, such as impact velocity, coating thickness, Young's modulus and Poisson's ratio on the stress peak of stress S11 were analyzed. Results show that: the position of tensile stress peak and compressive stress peak of stress S11 are far away from the impact center point with the increase of impact velocity. When coating thickness is equal to or greater than 10μm, the magnitude of tensile stress peak of stress S11 on the four coating surfaces does not change with the coating thickness at different impact velocities. When coating thickness is equal to or greater than 2μm, the magnitude of tensile stress peak of stress S11 of four coatings show a trend of increasing first and then decreasing with the increase of Young's modulus. Meanwhile, the larger the Poisson's ratio, the smaller the tensile stress peak of stress S11. After optimization, When coating thickness is 2μm, Poisson's ratio is 0.35 and Young's modulus is 800 GPa, the Fe2B coating has the strongest erosion resistance under the same impact conditions, followed by Cr3C2-NiCr, CrN, and the Al2O3- 13%TiO2 coating, Al2O3-13%TiO2 coating has the worst erosion resistance.

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Analysis of the photocatalytic activity of TiO2 coating on a glass as a criterion of its ability to self-cleaning

Technology audit and production reserves ◽

10.15587/2312-8372.2019.188072 ◽

2019 ◽

Vol 6 (1(50)) ◽

pp. 14-17

Author(s):

Mykola Plemyannikov

Keyword(s):

Photocatalytic Activity ◽

Tio2 Coating ◽

Self Cleaning

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Coating Nano-TiO2 on Optical Fiber with Al(H2PO4)3 Adhesive

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.485 ◽

2007 ◽

Vol 280-283 ◽

pp. 485-488 ◽

Cited By ~ 1

Author(s):

Yu Hong Zhao ◽

Jia Chen Liu ◽

Shun Li ◽

Yi Rong Liu

Keyword(s):

Optical Fiber ◽

Process Parameters ◽

Coating Thickness ◽

Fiber Surface ◽

Tio2 Coating ◽

Experimental Results ◽

Coating Process ◽

High Quality ◽

Tio2 Photocatalysis

To meet the need of optical fiber photoreactor designed by mechanism of TiO2 photocatalysis, nanometer TiO2 was coated on the surface of optical fiber by dipping nude fibers into an Al(H2PO4)3-contained TiO2 slurry. Effects of slurry conditions, including content of TiO2 and addition of Al(H2PO4)3 adhesive, on coating thickness and quality were determined. Coating process, especially the effect of coating times, was also concerned. Based on the experimental results, fitting slurry conditions and process parameters were suggested for obtaining high-quality TiO2 coating on optical fiber surface.

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