Enhanced Photocatalytic Activity over Flower-like Sphere Ag/Ag2CO3/BiVO4 Plasmonic Heterojunction Photocatalyst for Tetracycline Degradation

Wide spectral degradation of Norfloxacin by Ag@BiPO4/BiOBr/BiFeO3 nano-assembly: Elucidating the photocatalytic mechanism under different light sources.

Oxygen-containing organics have high potentials in the synthesis of functionalized organics, and their direct generation from alcohols and alkanes by photocatalytic processes under mild conditions has aroused tremendous interest. In the past decades, much progress has been made especially in the area of heterogeneous photocatalysis under visible light irradiation. In this article, we focus on the selective oxidation of alcohols and hydrocarbons into useful oxygen-containing organics, highlighting the recent advances. Despite the achievements, scale-up production of target oxygen-containing organics is not realized due to low catalytic efficiency. The efficacy of a photocatalyst is greatly dependent on its nature, and a slight change of physicochemical properties could result in significant deviation of photocatalytic activity. For better catalyst design, the related mechanistic aspects have to be understood thoroughly. Furthermore, factors such as reactor design and reaction conditions (e.g. light region and intensity, solvent, oxidant) are critical for optimization of performance. To realize practical application in organic synthesis, it is essential to clarify the underlying mechanism. Once the parameters for optimal performance have been determined, the design of an efficient photocatalytic reactor could be properly considered.

Heterogeneous photocatalysis for selective oxidation of alcohols and hydrocarbons

Rare earth metal doping into semiconductor oxides is considered to be an effective approach to enhance photocatalytic activity due to its ability to retard the electron–hole pair recombination upon excitation. Herein, we report the synthesis of different rare earth metal (La, Nd, Sm and Dy)-doped ZnO nanoparticles using a facile sol–gel route followed by evaluation of their photocatalytic activity by studying the degradation of methylene blue (MB) and Rhodamine B (RhB) under UV-light irradiation. Different standard analytical techniques were employed to investigate the microscopic structure and physiochemical properties of the prepared samples. The formation of the hexagonal wurtzite structure of ZnO was established by XRD and TEM analyses. In addition, the incorporation of rare earth metal into ZnO is confirmed by the shift of XRD planes towards lower theta values. All metal doped ZnO showed improved photocatalytic activity toward the degradation of MB, of which, Nd-doped ZnO showed the best activity with 98% degradation efficiency. In addition, mineralization of the dye was also observed, indicating 68% TOC removal in 180 min with Nd-doped ZnO nanoparticles. The influence of different operational parameters on the photodegradation of MB was also investigated and discussed in detail. Additionally, a possible photocatalytic mechanism for degradation of MB over Nd-doped ZnO nanoparticles has been proposed and involvement of hydroxyl radicals as reactive species is elucidated by radical trapping experiments.

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Comparative photocatalytic activity of sol–gel derived rare earth metal (La, Nd, Sm and Dy)-doped ZnO photocatalysts for degradation of dyes

Plasmonic photocatalysis has emerged as a prominent and growing field. It enables the efficient use of sunlight as an abundant and renewable energy source to drive a myriad of chemical reactions. For instance, plasmonic photocatalysis in materials comprising TiO2 and plasmonic nanoparticles (NPs) enables effective charge carrier separation and the tuning of optical response to longer wavelength regions (visible and near infrared). In fact, TiO2 -based materials and plasmonic effects are at the forefront of heterogeneous photocatalysis, having applications in energy conversion, production of liquid fuels, wastewater treatment, nitrogen fixation, and organic synthesis. This review aims to comprehensively summarize the fundamentals and to provide the guidelines for future work in the field of TiO2 -based plasmonic photocatalysis comprising the above-mentioned applications. The concepts and state-of-the-art description of important parameters including the formation of Schottky junctions, hot electron generation and transfer, near field electromagnetic enhancement, plasmon resonance energy transfer, scattering, and photothermal heating effects have been covered in this review. Synthetic approaches and the effect of various physicochemical parameters in plasmon-mediated TiO2 -based materials on performances are discussed. It is envisioned that this review may inspire and provide insights into the rational development of the next generation of TiO2 -based plasmonic photocatalysts with target performances and enhanced selectivities.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/smll.202101638

Recent Advances in Plasmonic Photocatalysis Based on TiO2 and Noble Metal Nanoparticles for Energy Conversion, Environmental Remediation, and Organic Synthesis.

Synthesis of sandwich-structured AgBr@Ag@TiO2 composite photocatalyst and study of its photocatalytic performance for the oxidation of benzyl alcohols to benzaldehydes

The factors that influence the photo-stability of Ag@AgBr plasmonic photocatalyst, such as light resource, electron/hole quencher, dye sensitizer, and atmosphere environment, were investigated in detail. It was revealed that Ag@AgBr can remain stable under weak light sources while it will become unstable under strong light sources. Electron quenchers are favorable to improving the stability of Ag@AgBr while hole quenchers do the opposite. Acting as a sensitizer, acid orange 7 dye is detrimental to the stability of Ag@AgBr. As for the atmospheric environment, air and oxygen-rich atmospheres are more favorable for keeping the stability of Ag@AgBr than vacuum atmosphere.

Study of the factors influencing the photo-stability of Ag@AgBr plasmonic photocatalyst

The invention relates to a method for preparing a silver/silver sulfide nanowire with a core shell structure. The method for preparing the material comprises the first step of scattering a silver nanowire regular in shape in a water solution containing a macromolecule protective agent, adding ferric chloride water solution to oxidize the surface of a silver wire to obtain a silver/silver chloride nanowire with a core shell structure; the second step of scattering the generated silver/silver chloride nanowire in the water solution, adding a water solution containing a sulphur source (thioacetamide, sodium sulfide or potassium sulfide), obtaining the silver/silver sulfide nanowire with the core shell structure; and the third step of performing hydrothermal crystallization on the obtained silver/silver sulfide nanowire. The method for preparing the silver/silver sulfide nanowire with the core shell structure has the advantages of being simple in preparation process and controllable in shape. The nanowire with the silver/silver sulfide core shell structure can be used for the fields of photoelectrodes and photocatalysis and the like.

Method for preparing silver/silver sulfide nanowire with core shell structure

Method for preparing coralline porous silver bromiodide/silver photocatalyst

The invention relates to a cube titanium dioxide vacant shell material and a preparing method thereof. The material comprises uniform cube titanium dioxide shells. The preparing method includes following steps: (1) slowly hydrolyzing titanium sulfate on surfaces of cube silver bromide microcrystals which are adopted as a template agent to obtain silver bromide/titanium dioxide of a core-shell structure; (2) subjecting the obtained silver bromide/titanium dioxide to hydro-thermal treatment; and (3) treating the silver bromide/titanium dioxide with a solution capable of dissolving silver bromide to remove the silver bromide template so as to obtain the cube titanium dioxide vacant shells. The material and the method have advantages of simple preparation processes, controllable morphology, and the like. The prepared material can be used for medical biomacromolecules, slow-release and controlled-release medicine carriers for medicines, and the like.

Wu Peiyi

Papers

Synthesis of sandwich-structured AgBr@Ag@TiO2 composite photocatalyst and study of its photocatalytic performance for the oxidation of benzyl alcohols to benzaldehydes

Study of the factors influencing the photo-stability of Ag@AgBr plasmonic photocatalyst

Method for preparing silver/silver sulfide nanowire with core shell structure

Method for preparing coralline porous silver bromiodide/silver photocatalyst

Preparing method of cube titanium dioxide vacant shell