Synthesis and Characterization of Ag@g−C 3 N 4 and Its Photocatalytic Evolution in Visible Light Driven Synthesis Of Ynone

Unlocking the potential of biogenic Ag@g-C3N4 in sustainable water purification: A Kinetic and Photocatalytic study

This research introduces a pioneering biogenic deposition-precipitation method for synthesis of Ag@g-C3N4 nanocomposites (NCs) employing fennel seed extract (FSE). This technique involves the reduction and capping of silver nanoparticles (AgNPs) onto g-C3N4, employing polyphenolic content of FSE, consequently establishing a strong Schottky junction. The, NCs were characterized through various spectroscopic and microscopic techniques, confirming successful biogenic deposition of AgNPs and purity of prepared nanomaterials. Further, the synthesized NCs were utilized for photocatalytic degradation of various hazardous pollutants viz. Rhodamine-B (Rh-B) dye, Tetracycline (TCy) antibiotic, Imidacloprid (IMD) insecticide and deactivation of E. coli microbes. Amongst the synthesized NCs, 3wt% Ag@g-C3N4 NCs exhibited superior photocatalytic mitigation of Rh-B (99.26%, k=90.4 x 10-3 min-1), TCy (96.86%, k=40.2 x 10-3 min-1), IMD (95.7%, k=34.96 x 10-3 min-1) and E. coli deactivation (99.5%, k = 49.19 x 10-3 min-1). Moreover, the rate constants revealed many-fold increase in photocatalytic degradation of pollutants, contrary to pristine g-C3N4 (k = 11.8 x 10-3 min-1). This investigation also unveils an intricate photocatalytic mitigation pathway for the aforementioned-contaminants, elucidating key role of superoxide radical anions in photocatalytic mitigation. One of the significant highlights of this research is the sustainable and cost-effective synthesis methodology involving fennel seeds, which not only ensures the wide availability of resources but also guarantees environmental safety, in alignment with green principles.

Graphitic carbon nitride (g-C3N4)-assisted materials for the detection and remediation of hazardous gases and VOCs

Graphitic carbon nitride (g-C3N4)-based materials are attracting attention for their unique properties, such as low-cost, chemical stability, facile synthesis, adjustable electronic structure, and optical properties. These facilitate the use of g-C3N4 to design better photocatalytic and sensing materials. Environmental pollution by hazardous gases and volatile organic compounds (VOCs) can be monitored and controlled using eco-friendly g-C3N4- photocatalysts. Firstly, this review introduces the structure, optical and electronic properties of C3N4 and C3N4 assisted materials, followed by various synthesis strategies. In continuation, binary and ternary nanocomposites of C3N4 with metal oxides, sulfides, noble metals, and graphene are elaborated. g-C3N4/metal oxide composites exhibited better charge separation that leads to enhancement in photocatalytic properties. g-C3N4/noble metal composites possess higher photocatalytic activities due to the surface plasmon effects of metals. Ternary composites by the presence of dual heterojunctions improve properties of g-C3N4 for enhanced photocatalytic application. In the later part, we have summarised the application of g-C3N4 and its assisted materials for sensing toxic gases and VOCs and decontaminating NOx and VOCs by photocatalysis. Composites of g-C3N4 with metal and metal oxide give comparatively better results. This review is expected to bring a new sketch for developing g-C3N4-based photocatalysts and sensors with practical applications.

Polymer Beads Decorated with Dendritic Systems as Supports for A3 Coupling Catalysts

Abstract

The gel type microscopic polymer beads bearing epoxy functionalities were modified using the two-stage procedures in order to decorate their surface with the moieties of the zeroth order PAMAM type dendrimer and different heterocyclic aldehydes (2-pyridinecarboxaldehyde, 2-pyrrolidinecarboxaldehyde, furfural or 2-thiophenecarboxaldehyde). The polymeric supports provided in this manner were then used for the immobilization of copper(II) ions. The resulting materials were characterized using different instrumental techniques (optical microscopy, SEM, FTIR microscopy, DR UV–Vis, ICP-OES, and thermal analysis). They were also used as catalysts in the model A3 coupling reaction of benzaldehyde, morpholine and phenylacetylene. The best catalytic activity was found for the polymeric catalyst bearing 2-pyridinecarboxaldehyde moieties. It turned out to be effective in the A3 coupling reactions included different benzaldehyde, alkyne, and secondary amine derivatives, as well. It could also be recycled several times without a significant decrease in its activity in the model A3 coupling reaction.

Graphic Abstract