A series of cerium ion-doped titanium dioxide (Ce 3+ –TiO2) catalysts with special 4 f electron configuration was prepared by a sol–gel process and characterized by Brunauer-Emmett-Teller method, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and also photoluminescence (PL) emission spectroscopy. The photocatalytic activity of Ce 3+ –TiO2 catalysts was evaluated in the 2-mercaptobenzothiazole (MBT) degradation in aqueous suspension under UV or visible light illumination. The experimental results demonstrated that the overall photocatalytic activity of Ce 3+ –TiO2 catalysts in MBT degradation was signigicantly enhanced due to higher adsorption capacity and better separation of electron-hole pairs. The experimental results verified that both the adsorption equilibrium constant (Ka) and the saturated adsorption amount (Gmax) increased with the increase of cerium ion content. The results of XPS analysis showed that the Ti 3+ ,C e 3+ , and Ce 4+ ions reside in the Ce 3+ –TiO2 catalysts. The results of DRS analysis indicated that the Ce 3+ –TiO2 catalysts had significant optical absorption in the visible region between 400 and 500 nm because electrons could be excited from the valence band of TiO2 or ground state of cerium oxides to Ce 4 f level. In the meantime, the dependence of the electron-hole pair separation on cerium ion content was investigated by the PL analysis. It was found that the separation efficiency of electron-hole pairs increased with the increase of cerium ion content at first and then decreased when the cerium ion content exceeded its optimal value. It is proposed that the formation of two sub-energy levels (defect level and Ce 4 f level) in Ce 3+ –TiO2 might be a critical reason to eliminate the recombination of

for 2-mercaptobenzothiazole degradation in aqueous suspension for odour control

Droplet impact on superhydrophobic surfaces: A review of recent developments

Hydrogen (H2) production is a latent feasibility of renewable clean energy. The industrial H2 production is obtained from reforming of natural gas, which consumes a large amount of nonrenewable energy and simultaneously produces greenhouse gas carbon dioxide. Electrochemical water splitting is a promising approach for the H2 production, which is sustainable and pollution-free. Therefore, developing efficient and economic technologies for electrochemical water splitting has been an important goal for researchers around the world. The utilization of green energy systems to reduce overall energy consumption is more important for H2 production. Harvesting and converting energy from the environment by different green energy systems for water splitting can efficiently decrease the external power consumption. A variety of green energy systems for efficient producing H2, such as two-electrode electrolysis of water, water splitting driven by photoelectrode devices, solar cells, thermoelectric devices, triboelectric nanogenerator, pyroelectric device or electrochemical water-gas shift device, have been developed recently. In this review, some notable progress made in the different green energy cells for water splitting is discussed in detail. We hoped this review can guide people to pay more attention to the development of green energy system to generate pollution-free H2 energy, which will realize the whole process of H2 production with low cost, pollution-free and energy sustainability conversion.

/pdf/water-splitting-from-electrode-to-green-energy-system-d7ob2et9ku.pdf

Water Splitting: From Electrode to Green Energy System

The triboelectric nanogenerator (TENG) is a new type of energy generator first demonstrated in 2012. TENGs have shown potential as power sources for electronic devices and as sensors for detecting mechanical and chemical stimuli. To date, studies on TENGs have focused primarily on optimizing the systems and circuit designs or exploring possible applications. Even though triboelectricity is highly related to the material properties, studies on materials and material designs have been relatively less investigated. This review article introduces recent progress in TENGs, by focusing on materials and material designs to improve the electrical output and sensing performance. This article discusses the current technological issues and the future challenges in materials for TENG. The development of materials for a technology that uses the movement of the human body to provide power has been reviewed by scientists in South Korea. A triboelectric nanogenerator converts mechanical energy into electricity by harnessing the fact that two surfaces rubbing against one another can become electrically charged. This is known as the triboelectric effect. One exciting use for these nanogenerators is in wearable electronics, where the motion of the body provides the power. Unyong Jeong and colleagues from Pohang University of Science and Technology have reviewed recent progress in material advances in the four main elements of a triboelectric nanogenerator: the charge-generating layer, the charge-trapping layer, the charge-collecting layer, and the charge-storage layer. These improvements all aim to increase the electrical output of such devices. Over the last decade, triboelectric nanogenerator (TENG) has been verified to be an effective way of converting daily mechanical energy into electric power or detecting various stimuli in the external environment. To promote the material researches in TENG, we introduce recent progresses in materials and material designs to improve the power generation and sensing performance. Also, we discuss on the future challenges and suggest possible approaches to solve the challenges.

/pdf/material-aspects-of-triboelectric-energy-generation-and-2j8tumglpy.pdf

Material aspects of triboelectric energy generation and sensors

Promoting smart cities into the 5G era with multi-field Internet of Things (IoT) applications powered with advanced mechanical energy harvesters

Theoretical study of micro/nano roughness effect on water-solid triboelectrification with experimental approach

Exploiting the silicon content of aluminum alloys to create a superhydrophobic surface using the sol–gel process

Special wetting surfaces with superhydrophilicity or superhydrophobicity have attracted great interest because of their potential for practical applications. However, since the special wetting surface may be used in a severe environment, including polluted air and seawater, it is necessary to develop a durable special wetting surface with excellent corrosion-resistance. Here, we report a new strategy for robust superhydrophilic or superhydrophobic green patina surfaces on copper substrates with superior corrosion resistance and adhesion strength, which have great potential for treating marine pollution. The as-prepared surfaces exhibited superhydrophilicity with underwater superoleophobicity or superoleophilicity with under-oil superhydrophobicity, which allowed them to selectively separate oil and water with high efficiency. More importantly, the surface displayed not only good mechanical stability but also chemical stability in corrosive liquids owing to the intrinsic properties of the patina and hydrophobic coating. Furthermore, the surface can be utilized as coating material for the decoration of building exteriors and prevention from surface fouling. We believe that our proposed method would make it possible to develop engineering materials that require robust anti-fouling, anti-frost, and anti-corrosion properties in marine environments.

/pdf/durable-superhydrophilic-phobic-surfaces-based-on-green-19aq2n7v8c.pdf

Durable superhydrophilic/phobic surfaces based on green patina with corrosion resistance†

Water waves are a continuously generated renewable source of energy. However, their random motion and low frequency pose significant challenges for harvesting their energy. Herein, we propose a spherical hybrid triboelectric nanogenerator (SH-TENG) that efficiently harvests the energy of low frequency, random water waves. The SH-TENG converts the kinetic energy of the water wave into solid–solid and solid–liquid triboelectric energy simultaneously using a single electrode. The electrical output of the SH-TENG for six degrees of freedom of motion in water was investigated. Further, in order to demonstrate hybrid energy harvesting from multiple energy sources using a single electrode on the SH-TENG, the charging performance of a capacitor was evaluated. The experimental results indicate that SH-TENGs have great potential for use in self-powered environmental monitoring systems that monitor factors such as water temperature, water wave height, and pollution levels in oceans.

/pdf/a-spherical-hybrid-triboelectric-nanogenerator-for-enhanced-25509y8x0r.pdf

Jeong-Won Lee

Papers

Theoretical study of micro/nano roughness effect on water-solid triboelectrification with experimental approach

Exploiting the silicon content of aluminum alloys to create a superhydrophobic surface using the sol–gel process

Durable superhydrophilic/phobic surfaces based on green patina with corrosion resistance†

A Spherical Hybrid Triboelectric Nanogenerator for Enhanced Water Wave Energy Harvesting

Fabrication of a superhydrophobic surface with fungus-cleaning properties on brazed aluminum for industrial application in heat exchangers