High-Efficacy Hierarchical Dy2O3/TiO2 Nanoflower toward Wastewater Reclamation: A Combined Photoelectrochemical and Photocatalytic Strategy

Unraveling the potential of sonochemically achieved DyMnO3/Dy2O3 nanocomposites as highly efficient visible-light-driven photocatalysts in decolorization of organic contamination

In the present day, the widespread presence of lingering contaminants in ecosystems has prompted scientists to develop novel semiconductor nanoarchitectures that assist in photocatalytic reactions mediated by visible light. As a result, we propose to prepare a series of Dy-Mn-O based nano-catalysts using a sonochemical approach utilizing various ionic phases of surfactants as structure-directing agents. In this study, X-ray diffraction (XRD) and Rietveld refinement techniques were used to explore the fundamental effects of surfactants on the compositional-structural features of the materials. In terms of morphological profiles, DyMnO3/Dy2O3 (DM) nanostructures fabricated with Triton X-80 as a structure-directing agent showed the best uniformity with an acceptable size range between 14.14 and 52.35 nm. In the visible-light-driven photocatalytic domain, these nanocomposites provide high responsiveness based on their optical band gap value of 2.0 eV. According to our findings, two individual factors affect dye activity, namely dye type and concentration, which is why a high decomposition efficiency of 78.8% was obtained for 10 ppm Acid violet (AV) using DyMnO3/Dy2O3 nanocomposites after 120 min of exposure to visible light. Furthermore, radical quenching test confirmation confirmed the mechanistic behind the degradation process. This indicates that active species of O2•- and •OH may play a significant role in photocatalysis. As a result of repeated processes over three consecutive cycles, binary DyMnO3/Dy2O3 nanocomposites had an efficiency of 64.4% in removing dyes from the environment, indicating their high stability.

Altass H, Althagafi II, Ahmed SA. Fabrication of Direct Z-Scheme CoNiWO4/Ph-gC3N4 Heterocomposites: Enhanced Photodegradation of Bisphenol A and Anticancer Activity

Photocatalysis is realized by the design of a visible-light-active catalyst with robust redox capacity and broad absorption. In this study, a series of novel Z-scheme CoNiWO4/Ph-gC3N4 photocatalysts are synthesized to improve their redox property and photocatalytic activity toward broad visible light absorption. An intimate stable heterojunction is made between cobalt-nickel tungstate (CoNiWO4) and phenyl-doped graphitic carbon nitride (Ph-gC3N4), and its physicochemical properties are studied. The bifunctional properties of all of the synthesized materials were assessed by studying the decomposition of bisphenol A (BPA) and methyl orange (MO) dye as model pollutants, followed by an evaluation of their anticancer activity on human lung cancer cell lines. The photocatalyst with 20 wt % CoNiWO4 heterocomposite showed an enhanced response toward the removal of cancerous cells. The synthesized pristine CoNiWO4 and Ph-gC3N4 exhibit well-matched band structures and, hence, make it easier to create a Z-scheme heterocomposite. This may increase the lifetime of photoinduced charge carriers with a high redox power, thereby improving their photocatalytic and anticancer activity. An extensive analysis of the mechanism demonstrates that hydroxyl radicals (•OH) and superoxide radical anions (•O2-) are responsible for the degradation of organic compounds via Z-scheme charge transfer approach. These findings point toward a new route for creating effective Co-Ni tungstate-based direct Z-scheme photocatalysts for various redox processes, particularly the mineralization of resistant organic molecules.

Novel Type-II Heterojunction Binary Composite (CdS/AgI) with Outstanding Visible Light-Driven Photocatalytic Performances toward Methyl Orange and Tetracycline Hydrochloride

In this study, an effective type-II heterojunction CdS/AgI binary composite was constructed by an in situ precipitation approach. To validate the successful formation of heterojunction between AgI and CdS photocatalysts, the synthesized binary composites were characterized by various analytical techniques. UV-vis diffuse-reflectance spectroscopy (UV-vis DRS) revealed that heterojunction formation led to a red shift in the absorbance spectra of the CdS/AgI binary composite. The optimized 20AgI/CdS binary composite showed a least intense photoluminescence (PL) peak indicating highly improved charge carrier (e^-/h⁺ pairs) separation efficiency. The photocatalytic efficiency of the synthesized materials was assessed based on the degradation of methyl orange (MO) and tetracycline hydrochloride (TCH) in the presence of visible light. Compared to bare photocatalysts and other binary composites, the 20AgI/CdS binary composite showed the highest photocatalytic degradation performances. Additionally, the trapping studies showed that superoxide radical anion (O₂^•-) was the most dominant active species involved in photodegradation processes. Based on the results of active species trapping studies, a mechanism was proposed to describe the formation of type-II heterojunctions for CdS/AgI binary composite. Overall, the synthesized binary composite has tremendous promise for environmental remediation due to its straightforward synthesis approach and excellent photocatalytic efficacy.

Highly efficient and stable AgI-CdO nanocomposites for photocatalytic and antibacterial activity

For the last several decades, semiconducting materials and nanocomposites have received a lot of interest in generating highly efficient photocatalysts to destroy organic pollutants and eradicate bacteria. This study uses a simple deposition and precipitation approach at ambient temperature to create a unique and efficient AgI-CdO heterojunction. DRS, IR, SEM, EDS, XRD, EIS, and TEM were utilized to identify the material. SEM and TEM investigation depict the completely spherical, hexagonal forms and zigzag cubes for synthesized AgI-CdO. The EDX spectra reveal the presence of Ag, I, Cd, and O elements without impurity peaks showing that the prepared samples are highly pure. The activity of the synthesized materials was tested by degrading two different chromophoric dyes and a drug derivative (paracetamol) in an aqueous suspension under visible light. In addition, the activity of the most active catalyst was compared with Degussa P25, Fenton's reagent, and under sunlight for degradation of MB and RhB under similar conditions. Photolysis of paracetamol was also looked at using HPLC to identify intermediates formed in the photo-oxidation process. In addition, antibacterial activity was also investigated with the synthesized CdO-AgI nanocomposite in vitro against human pathogenic bacterial strains and compared with that of pure materials like AgI and standard ampicillin. The results showed excellent activity with the composite material, which could be due to the higher surface areas and the interactions between AgI and CdO nanoparticles. Quenching investigations revealed O₂˙^- and holes are principal reactive species. A viable photocatalytic degradation mechanism for organic pollutant elimination over the AgI-CdO nanocomposite has been sketched out based on the obtained results.