Constructing α-Fe2O3/g-C3N4/SiO2 S-scheme-based heterostructure for photo-Fenton like degradation of rhodamine B dye in aqueous solution.

This work successfully fabricated graphitic carbon nitride and magnetically recoverable α-Fe2O3/g-C3N4/SiO2 photo-Fenton catalysts using thermal polycondensation and in situ-simple precursor drying-calcination process, respectively, was examined for model synthetic rhodamine B (RhB) dye in the presence of H2O2 and acidic pH under simulated visible light irradiation. An aqueous suspension of the reaction mixture of dye-containing wastewater was fully degraded and reached 97% of photo-Fenton degradation efficiency within 120 min followed by the production of hydroxyl radical (•OH). The dominant hydroxyl radical position generated surface charge, electrostatic potential distribution, and average local ionization potential, which contributed to the complete mineralization of RhB dye, according to the density functional theory (DFT) calculations. HPLC and GCMS experiments were performed to examine the degradation fragments of RhB and draw a plausible mechanistic pathway which showed that RhB degradation generated a series of N-deethylated products, followed by a one-time ring-opening, which indicated that photosensitization induced a photocatalysis reaction mechanism.

Rational design, structure properties, and synthesis strategies of dual-pore covalent organic frameworks (COFs) for potent applications: A review.

Dual-pore covalent organic frameworks (COFs) offer a molecular scaffold for introducing building blocks into periodically organized polygonal skeletons to produce fascinating structural features. The rapid development of this material has attracted intensive interest from researchers with diverse expertise. This review selects the leading scientific findings about dual-pore COFs and highlights their functions and perspectives on design, structure properties, and synthesis strategies. Dual-pore COFs, as newly hetero-pore COFs by integrating particular pores into one polygonal skeleton, have been compared to conventional COFs. Dual-pore COFs display hierarchical/heterogeneous porosities and homogeneous porosity, which endow them with exceptional features involving mass diffusion, charge transfer, and large surface area with abundant active sites. Additionally, the strategic dual-pore design by opting for different approaches, such as integration of [D2h + C2] symmetries, kagome-type lattices, and other symmetric arrangements of monomers, are inclusively discussed. Identification and construction of dual-pores in COFs via optimal synthetic methods, such as desymmetrization, multiple linking sites, and orthogonal reactions, are highlighted as the primary pore engineering routes to simultaneously regulate the growth and alter the characteristics of COFs for promising applications. Lastly, a focused discussion on various challenges and critical fundamentals of dual-pore engineering is successfully outlined, with potential prospects of introducing dual-pore in COFs.