Development of Three-Dimensional Nickel-Cobalt Oxide Nanoflowers for Superior Photocatalytic Degradation of Food Colorant Dyes: Catalyst Properties and Reaction Kinetic Study

Role of polymer template in crystal structure and photoactivity of Cu-TiO2 heterojunction nanostructures towards environmental remediation

Exploring porous heterojunction nanomaterials as a photocatalyst for water depollution strategies towards environmental restoration is exceedingly difficult in the perspective of sustainable chemistry. Herein, we first report a porous Cu-TiO₂ (TC40) heterojunction by using microphase separation of a novel penta-block copolymer (PLGA-PEO-PPO-PEO-PLGA) as a template through an evaporation induced self-assembly (EISA) method having nanorod-like particle shape. Furthermore, three types of photocatalysts were made with or without template polymer to clarify the function of that template precursor on the surface and morphology, as well as which variables are the most critical for a photocatalyst. TC40 heterojunction nanomaterial displayed high BET surface area along with lower band gap value viz.2.98 eV compare the other and all of these features make it a robust photocatalyst for wastewater treatment. In order to improve water quality, we have carried out experiments on the photodegradation of methyl Orange (MO), highly toxic pollutants that cause health hazards and bioaccumulate in the environment. Our catalyst, TC40 exhibits the 100% photocatalytic efficiency towards MO dye degradation in 40 and 360 min at a rate constant of 0.104 ± 0.007 min^-1 and 0.440 ± 0.03 h^-1 under UV + Vis and visible light irradiation respectively.

Photocatalytic Degradation of Food and Juices Dyes via Photocatalytic Nanomaterials Synthesized through Green Synthetic Route: A Systematic Review

The unavailability of non-poisonous and hygienic food substances is the most challenging issue of the modern era. The uncontrolled usage of toxic colorant moieties in cosmetics and food manufacturing units leads to major threats to human life. The selection of environmentally benign approaches for the removal of these toxic dyes has gained the utmost attention from researchers in recent decades. This review article's main aim is the focus on the application of green-synthesized nanoparticles (NPs) for the photocatalytic degradation of toxic food dyes. The use of synthetic dyes in the food industry is a growing concern due to their harmful effects on human health and the environment. In recent years, photocatalytic degradation has emerged as an effective and eco-friendly method for the removal of these dyes from wastewater. This review discusses the various types of green-synthesized NPs that have been used for photocatalytic degradation (without the production of any secondary pollutant), including metal and metal oxide NPs. It also highlights the synthesis methods, characterization techniques, and photocatalytic efficiency of these NPs. Furthermore, the review explores the mechanisms involved in the photocatalytic degradation of toxic food dyes using green-synthesized NPs. Different factors that responsible for the photodegradation, are also highlighted. Advantages and disadvantages, as well as economic cost, are also discussed briefly. This review will be advantageous for the readers because it covers all aspects of dyes photodegradation. The future feature and limitations are also part of this review article. Overall, this review provides valuable insights into the potential of green-synthesized NPs as a promising alternative for the removal of toxic food dyes from wastewater.

g-C3N4-wrapped nickel doped zinc oxide/carbon core-double shell microspheres for high-performance photocatalytic hydrogen production

The development of efficient heterojunctions with enhanced photocatalytic properties is considered a promising approach for photocatalytic hydrogen production. In this study, graphitic carbon nitride (g-C₃N₄)-wrapped nickel-doped zinc oxide/carbon (Ni-ZnO@C/g-C₃N₄) core-double shell heterojunctions with unique core-double shell structures were employed as efficient photocatalysts through an innovative approach. Ni doping can enhance the intensity and range of visible light absorption in ZnO, and the carbon core coupled with the hollow double-shell structure can accelerate the charge transfer rate and improve the photon utilization efficiency. Meanwhile, the construction of the Z-scheme heterojunction extended the electron-hole pair transport path. In addition, the Z-scheme charge-transfer mechanism of Ni-ZnO@C/g-C₃N₄ under simulated sunlight was verified by photoluminescence (PL) and electron spin resonance (ESR) experiments. As a result, the obtained photocatalyst acquired a high hydrogen evolution rate of 336.08 μmol g^-1h^-1, which is 36.49 times higher than that of pristine ZnO. Overall, this work may provide a pathway for the construction of highly efficient photocatalysts with unique core-double shell structures.

Synergistic Effects of Redox Couples and Oxygen Vacancies Improve the Tetracycline Degradation Property of La2NiMnO6

Improving the e^- and h⁺ separation efficiency and promoting the production of more radicals is the key to improving the degradation efficiency of catalytic degradation of antibiotics. On the other hand, intermediate analysis of antibiotics in the dark adsorption and light irradiation process is very important to clarify the entire antibiotic degradation pathway. Here, the La₂NiMnO₆ (LNMO) catalyst was prepared by the sol-gel method and the calcination method. By changing the calcination temperature (800, 900, and 1000 °C), the LNMO-based catalysts were successfully formed, abbreviated as L-800, L-900, and L-1000. XPS measurements demonstrated the presence of Mn⁴⁺, Mn³⁺, Mn²⁺, and oxygen vacancies (OVs) in the LNMO-based catalysts. Analysis of PL, PC, EIS, and TR-PL demonstrated that L-900 had the highest separation efficiency and fastest carrier mobility. The LNMO-based catalysts were used to degrade tetracycline (TC). With the optimized catalyst L-900, the decomposition rate of TC reached 99.57% in 120 min. The entire TC degradation pathway was analyzed according to LC-MS measurements. Radical trap experiments and ESR technology revealed that the synergistic effect of Mn⁴⁺/Mn³⁺, Mn⁴⁺/Mn²⁺, and OVs not only effectively separated e^- and h⁺ but also facilitated the formation of superoxide radicals (^•O₂^-) to accelerate TC degradation. Radicals ^•OH, h⁺, and ^•O₂^- all contributed to TC deterioration in increasing order of importance. In addition, XPS measurements of the L-900 catalyst before and after use indicated that Mn⁴⁺/Mn³⁺, Mn⁴⁺/Mn²⁺, and OVs were not reactants but mediators of e^- and h⁺. Finally, the mechanism of TC degradation with the LNMO-based catalysts was discussed. This work provided new material for TC degradation in the wastewater.