Thermally and photocatalytically active multifunctional porous coatings for high temperature applications

Fabrication of durable self-cleaning photocatalytic coating with long-term effective natural light photocatalytic degradation performance

The practical application of photocatalytic coating has been greatly challenged in terms of its long-term effective natural light photocatalytic degradation due to its vulnerability and easy contamination caused by poor self-cleaning properties. In this work, photocatalytic coating with self-cleaning properties was prepared by spraying fluorinated dual-scale TiO₂ on the inorganic lithium silicate adhesive, enabling excellent durability and long-term effective photocatalytic degradation performance under natural light. The coating exhibits superhydrophobic properties even after abrasion testing, acid and alkali immersion testing, and UV aging, laying a foundation for the practical use. Moreover, the coating can be applied to various substrates and its excellent self-cleaning properties make it resistant to particulate and liquid contamination that may occur in the environment. Besides, we evaluated the photocatalytic stability of the coating by subjecting it to acidic and alkaline environments and high pollution concentrations. Furthermore, benefiting from the synergistic effect of photocatalytic and self-cleaning properties, the coating achieves long-term effective photocatalytic degradation of dye wastewater under natural light, which still has a high removal rate of 95.8% for methylene blue even after 30 cycles of use. Meanwhile, due to the coating's excellent durability, the long-term quality loss rate of the coating still remained below 0.3%, which avoids the risk of secondary environmental pollution caused by nanoparticle leakage. Therefore, these excellent properties enable the coating to have a broad range of application prospects for the treatment of pollutants in water.

Improved Capture and Removal Efficiency of Gaseous Acetaldehyde by a Self-Powered Photocatalytic System with an External Electric Field

Using clean and sustainable stochastic energy from the environment to eliminate pollution caused by gaseous aldehydes would be an effective strategy to achieve the sustainable development of energy and preserve the environment. Here, a piston-based triboelectric nanogenerator (P-TENG) was used to enhance gaseous acetaldehyde absorption and photocatalytic degradation. An external electric field could be generated on a conductive substrate by the P-TENG, converting wind energy into electricity. This made it possible to efficiently degrade gaseous acetaldehyde in the photocatalytic system. Driven by a light breeze (3.0 m/s), the acetaldehyde removal rate of the system reached 63% within 30 min. The presence of an external electric field could generate more hydroxyl radicals (^•OH), superoxide radicals (^•O₂^-), and holes (h⁺), which has a positive effect on the photocatalytic degradation of acetaldehyde. The design and concept of this study not only realized the efficient conversion of renewable and sustainable random energy but also could be applied to the efficient removal of gaseous aldehydes, providing an effective way to create a cleaner environment.

Photo-catalytic degradation of mixed gaseous HCHO and C6H6 in paper mills: Experimental and theoretical study on the adsorption behavior simulation and catalytic reaction mechanism

VOCs in paper mills have severely exceeded the emission standards and their photo-catalytic degradations should focus on the experimental and theoretical studies. This work used TiO₂ colloid as catalyst to study the photo-catalytic degradations of mixed HCHO and C₆H₆ at five mixing ratios. The adsorption behaviors of pure forms and mixtures on the TiO₂ (101) surface were simulated using density functional theory (DFT), and their catalytic reaction mechanisms were also analyzed. The following results were found: (1) With increasing initial concentration, the enhanced adsorption and easy degradation interpreted the increased degradation rate for pure HCHO, while the counteractions of enhanced adsorption and inhibited catalytic reaction kept the constant degradation rate for pure C₆H₆. (2) For their mixtures, the HCHO degradation was inhibited at high C₆H₆ concentration due to the inhibited adsorption and catalytic reaction of HCHO. The C₆H₆ degradation was slightly weakened at high HCHO concentration and then restored to the normal degradation rate of C₆H₆, which could be attributed to the weakened adsorption of C₆H₆ and the easy degradation of HCHO in the initial stage. The combined experimental, simulation, and theoretical results provides sufficient information to understand the photo-catalytic degradation process for mixed gaseous pollutants in different realistic environments.