A stable novel nanostructure of ZnFe2O4 based nanocomposite for improved photoelectrocatalytic and photocatalytic activities

Synthesizing Ag2Ox(3 wt%)-loaded ZnFe2O4 photocatalysts for efficiently saving polluted aquatic ecosystems

Herein, we report an Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts synthesized by co-precipitation and incipient wet impregnation approach for acetamiprid degradation, antibacterial, antioxidant, and toxicity assay. Initially, bare ZnFe2O4 nanostructures were made through a simple co-precipitation method. In the second step, 3 wt% of various transition metal oxides (CuOx, ZrOx, and Ag2Ox) were embedded on the surface of ZnFe2O4 photocatalysts via a wet impregnation method. Further, the prepared photocatalysts were systematically characterized using XRD, FTIR, FE-SEM, BET, HRTEM, and XPS analysis. The optimum Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts revealed higher degradation efficiencies for acetamiprid under sunlight irradiation. Additionally, the Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts showed more effective antioxidant and antibacterial activity than blank and bare ZnFe2O4 nanomaterials. The enriched catalytic efficiency can be accredited to the 3 wt% of Ag2Ox NPs loaded on ZnFe2O4 nanomaterials, possibly due to the boosted transport properties of the electron-hole pairs. This study will provide a new avenue for the development of simple and effective photocatalysts for efficiently saving polluted aquatic ecosystems.

Zinc ferrite-based p-n homojunction with multi-effect for efficient photoelectrochemical water splitting

A novel one-dimensional core-shell zinc ferrite (ZnFe₂O₄) p-n homojunction is prepared by a facile two-step hydrothermal method. The core-shell homojunction is constructed by decorating p-type Ni-ZnFe₂O₄ (shell) onto n-type ZnFe₂O₄ (core). As expected, significant enhancement in the photocurrent density of the developed homojunction is realized compared to that of pristine ZnFe₂O₄ (6.64 times that of pristine ZnFe₂O₄). This improvement is ascribed to the fact that the ZnFe₂O₄ homojunction has multiple optimization effects, namely, a built-in electric field and active sites on Ni-ZnFe₂O₄, which are beneficial to carrier separation and transport. This study paves a promising pathway for the use of ion doping to design high-quality p-n homojunctions with multiple effects for enhancing charge separation in the photoelectrochemical water splitting configuration.

Achieving cadmium selenide-decorated zinc ferrite@titanium dioxide hollow core/shell nanospheres with improved light trapping and charge generation for photocatalytic hydrogen generation

We report the rational design and fabrication of magnetically separable zinc ferrite@titanium dioxide (ZnFe₂O₄@TiO₂) hollow core/shell nanospheres as photocatalysts for efficient H₂ evolution by loading the TiO₂ shell layer on the prepared ZnFe₂O₄ hollow nanospheres using the kinetics-controlled coating method. Meanwhile, the incident light absorption, photogenerated charge transfer and separation and photocatalytic hydrogen evolution activity were remarkably improved by well anchoring cadmium selenide (CdSe) quantum dots on the ZnFe₂O₄@TiO₂ hollow core/shell nanospheres. This unique design integrates the structural and functional merits of the ZnFe₂O₄, TiO₂, and CdSe quantum dots into porous hollow nanospheres with the double-shell heterostructure. This design significantly accelerates the separation and transport of photogenerated charge carriers, enhances the light absorption, and offers more active sites for the photocatalytic H₂ evolution reaction. Benefitting from the unique structural and component merits, the optimized magnetically separable ZnFe₂O₄@TiO₂/CdSe hollow core/shell nanospheres exhibit excellent photocatalytic hydrogen evolution performance with a high H₂ generation rate (266.0 μmol h^-1·g^-1) and high stability.

Use mechanochemical activation to enhance interfacial contaminant removal: A review of recent developments and mainstream techniques

Interfacial processes, including adsorption and catalysis, play crucial roles in environmental contaminant removal. Mechanochemical activation (MCA) emerges as a competitive method to improve the performance of adsorbents and catalysts. The development and application of MCA in the last decades are thereby systematically reviewed, particularly highlighting its contribution to interfacial process modulation. Two typical apparatuses for MCA are ball milling (BaM) and bead milling (BeM). Compared to BaM, BeM is able to yield a much higher MCA intensity, because it could pulverize bulk solid particles to nearly 100 nm. Since MCA intensity on the adsorbents and catalysts is directly responsible for the contaminant removal afterwards, quantitative and qualitative determination methods for valid MCA intensity are introduced. MCA benefits both the adsorption kinetics and capacity of powdered activated carbon by increasing the specific surface area. Carbon oxidation should be given an additional attention, but potentially favors the adsorption of heavy metals. MCA favors the catalyst performance by providing abundant surface functional group and increasing the free energy in the near-surface region. Finally, the future research needs are identified.