Preparation of cerium and sulfur codoped TiO2 nanoparticles based photocatalytic activity with enhanced visible light

Facile synthesis of efficient MoS2-coupled graphitic carbon nitride Z-scheme heterojunction nanocomposites: photocatalytic removal of methylene blue dye under solar light irradiation

Among different types of semiconductor photocatalysts, MoS₂ hybridized with graphitic carbon heterojunction has developed the most promising "celebrity" due to its static chemical properties, suitable band structure, and facile synthesis. Physiochemical and surface characterizations were revealed with structural, electronic, and optical analysis. Diffused reflectance spectroscopy evidenced the energy band gap tailoring from 2.62 eV for pure g-C₃N₄ and 1.68 eV for MoS₂ to 2.12 eV for the hybridized heterojunction nanocomposite. Effective electron/hole pair separation, rise in redox species, and great utilization of solar range because of band gap modifying leading to greater degradation efficacy of g-C₃N₄/MoS₂ heterojunction. The photocatalytic degradation with MoS₂/g-C₃N₄ heterojunction catalyst to remove methylene blue dye was remarkably enriched and much higher than g-C₃N₄. By carefully examining the stimulus aspects, a probable mechanism is suggested, assuming that the concurring influence of MoS₂ and g-C₃N₄, the lesser crystallite size, and more solubility in aquatic solution furnish the efficient e^--h⁺ pair separation and tremendous photocatalytic degradation activity. This work delivers a novel idea to improve the efficient MoS₂/g-C₃N₄ heterojunction for improved photocatalytic degradation in environmental refinement.

Construction of novel g-C3N4 coupled efficient Bi2O3 nanoparticles for improved Z-scheme photocatalytic removal of environmental wastewater contaminant: Insight mechanism

Recently, the major environmental pollution produced by the release of wastewater in liquid type is one of the most extensive forms of foremost pollution in water ecosystems. In this article, the Bi₂O₃/g-C₃N₄ nanocomposite with a direct Z-scheme was effectively obtained by a facile hydrothermal system. The crystal structures, surface morphology, chemical composition, and the optical belongings of the as-obtained composite catalysts were examined by Power XRD, FT-IR spectra, High-resolution XPS spectra, FE-SEM images with EDX spectra, High-resolution TEM images, UV-Vis DRS, and PL spectra respectively. Furthermore, the photocatalytic performance was assessed by the degradation of aqueous Rhodamine B (Rh B) dye under visible-light exposure. The Bi₂O₃/g-C₃N₄ composite photocatalysts (PCs) showed the maximum photo-degradation efficiency through a rate constant value of 0.0149 min^-1, which is 4.9 and 5.3 folds superior to Bi₂O₃, and GCN, respectively. The better GBO2 nanocomposite PCs showed a superior photocatalytic degradation performance (>82%) of aqueous Rh B dye after five successive recycles. Moreover, based on these outcomes of the radical scavenging test, a direct and effective Z-scheme photocatalytic charger transfer mechanism was also projected. Finally, the reusability of the as-obtained Bi₂O₃/g-C₃N₄ nanocomposite has better stability and reusability, which was a favourable applicant for wastewater handling.

Enhancement in the visible light induced photocatalytic and antibacterial properties of titanium dioxide codoped with cobalt and sulfur

In this study, the sol-gel technique was used to develop Cobalt Sulfur codoped Titanium Dioxide (Co-S codoped TiO₂) photocatalysts. For structural analysis of the prepared resultant TiO₂ samples, XRD, FTIR, UV-Vis DRS, SEM, HR-TEM and EDX measurements were used to describe the produced photocatalysts. The characterization findings indicate that the synthesized nanoparticles possessed great crystallinity, high purity, and superior optical characteristics. For the methylene blue (MB) degradation process, Co-S codoped TiO₂ nanoparticles were tested for their photocatalytic degradation performance. The Co-S codoped TiO₂ nanoparticles had improved catalytic activity when compared with pure, Co-doped, S-doped TiO₂ and decomposed 93% of MB in 120 min. When compared to pure and doped TiO₂, the catalysts of Co-S codoped TiO₂ showed a synergistic effect and improved the performance of the catalysts. Furthermore, the antibacterial applications of synthesized Co-S codoped TiO₂ nanoparticles was studied against E. coli (Gram negative) and S. aureus (Gram positive) bacteria and exhibited strong antibacterial activity against the selected strains.

Improving Wastewater Treatment by Triboelectric-Photo/Electric Coupling Effect

The ability to meet higher effluent quality requirements and the reduction of energy consumption are the biggest challenges in wastewater treatment worldwide. A large proportion of the energy generated during wastewater treatment processes is neglected and lost in traditional wastewater treatment plants. As a type of energy harvesting system, triboelectric nanogenerators (TENGs) can extensively harvest the microscale energies generated from wastewater treatment procedures and auxiliary devices. This harvested energy can be utilized to improve the removal efficiency of pollutants through photo/electric catalysis, which has considerable potential application value in wastewater treatment plants. This paper gives an overall review of the generated potential energies (e.g., water wave energy, wind energy, and acoustic energy) that can be harvested at various stages of the wastewater treatment process and introduces the application of TENG devices for the collection of these neglected energies during wastewater treatment. Furthermore, the mechanisms and catalytic performances of TENGs coupled with photo/electric catalysis (e.g., electrocatalysis, photoelectric catalysis) are discussed to realize higher pollutant removal efficiencies and lower energy consumption. Then, a thorough, detailed investigation of TENG devices, electrode materials, and their coupled applications is summarized. Finally, the intimate coupling of self-powered photoelectric catalysis and biodegradation is proposed to further improve removal efficiencies in wastewater treatment. This concept is conducive to improving knowledge about the underlying mechanisms and extending applications of TENGs in wastewater treatment to better solve the problems of energy demand in the future.

Effect of Fe-N Codoping on the Optical Properties of TiO2 for Use in Photoelectrolysis of Water

TiO₂ nanoparticles were synthesized by green chemistry where organic solvents are replaced by an aqueous extract solution of lemongrass leaves that act as a reducer and growth-stopper agent. The nanoparticles were codoped with N-Fe to modify the absorption range in the electromagnetic spectrum and were characterized by Fourier-transform infrared (FTIR), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), and UV-vis/diffuse reflectance spectroscopy (DRS). The modified samples with Fe and N resulted in smaller nanoparticle size values than pure TiO₂. Similarly, the band-gap energy for doped nanoparticles decreased to 2.22 eV in relation to the value of 3.09 eV for pure TiO₂, due to the introduction of new energy levels.

Nickel and sulfur codoped TiO2 nanoparticles for efficient visible light photocatalytic activity

In this work, Nickel (Ni) and sulfur (S) codoped TiO2 nanoparticles were prepared by a sol-gel technique. The as-prepared catalyst was characterized using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), FT-Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (DRS) for investigating crystal structure, crystal phase, particle size and bandgap energy of these samples. The photocatalytic performances of all the prepared catalysts have been investigated for the degradation of methylene blue (MB) under visible light irradiation. It was noticed that Ni-S codoped TiO2(Ni-S/TiO2) nanoparticles exhibited much higher photocatalytic activity compared with pure, Ni and S doped TiO2 due to higher visible light absorption and probable decrease in the recombination of photo-generated charges. It was decided that the great visible light absorption was created for codoped TiO2 by the formation of impurity energy states near both the edges of the collection, which works as trapping sites for both the photogenerated charges to decrease the recombination process.

Effects of Ag0-modification and Fe3+-doping on the structural, optical and photocatalytic properties of TiO2

The reasons for the photocatalytic activity of 1% Ag–TiO₂ > pure TiO₂ > 1% Ag/1% FeTiO₂ > 1% Fe–TiO₂ are investigated systematically.

Photocatalytic degradation of metronidazole and methylene blue by PVA-assisted Bi2WO6–CdS nanocomposite film under visible light irradiation

The enhanced photocatalytic performance of nanocomposite is synthesized via the hydrothermal method and characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), UV–visible diffuse reflectance spectroscopy (UV–Vis DRS) and photoluminescence spectroscopy (PL). Under visible light irradiation, PVA assisted Bi2WO6–CdS nanocomposite film displayed enhanced photocatalytic efficiency and inhibition of photocorrosion as compared with pure CdS, pure Bi2WO6 and Bi2WO6–CdS composite. The PVA assisted Bi2WO6–CdS composite film catalyst showed stable catalytic performance until seven successive runs with 92% of methylene blue(MB) degradation, and easy to recover after degradation of organic pollutant. PVA assisted Bi2WO6–CdS nanocomposite film has optimal band edge position for superior photocatalytic degradation. Furthermore, the trapping experiment was carried out using different scavenger for active species. Among the active species, OH· are the most responsive species which play a vital role in the degradation of metronidazole and MB.