Synchronous construction of a porous intramolecular D-A conjugated polymer via electron donors for superior photocatalytic decontamination

Boosting Photocatalytic Performance of ZnO Nanowires via Building Heterojunction with Conjugated 2,4,6-Triaminopyrimidine-g-C3N4

Photocatalysis is one of the most effective ways to solve environmental problems by solving pollutants. This article designed and prepared a conjugated system of 2,4,6-triaminopyrimidine-g-C3N4 (TAP-CN) to modify ZnO NWs. We systematically studied the photocatalytic performance of ZnO NWs modified with different ratios of TAP-CN. The results showed that 9 wt% TAP-CN-30/ZnO NWs had the best degradation effect on Rhodamine B dye. The degradation rate was 99.36% in 80 min. The excellent degradation performance was attributed to the TAP-CN conjugated system promoting photo-generated charge transfer. This work provided guidance for designing efficient composite catalysts for application in other renewable energy fields.

DFT Predirected Molecular Engineering Design of Donor-Acceptor Structured g-C3N4 for Efficient Photocatalytic Tetracycline Abatement

The photocatalytic environmental decontamination ability of carbon nitride (g-C3N4, CN) typically suffers from their inherent structural defects, causing rapid recombination of photogenerated carriers. Conjugating CN with tailored donor-acceptor (D-A) units to counteract this problem through electronic restructuring becomes a feasible strategy, where confirmation by density functional theory (DFT) calculations becomes indispensable. Herein, DFT is employed to predirect the copolymerization modification of CN by benzene derivatives, screening benzaldehyde as the optimal electron-donating candidate for the construction of reoriented intramolecular charge transfer path. Experimental characterization and testing corroborate the formation of a narrowed bandgap as well as high photoinduced carrier separation. Consequently, the optimal BzCN-2 exhibited superior photocatalytic capacity in application for tetracycline hydrochloride degradation, with 3.73 times higher than that of CN. Besides, the BzCN-2-based photocatalytic system is determined to have a toxicity-mitigating effect on TC removal via T.E.S.T and prefers the removal of dissociable TC2- species under partial alkalinity. This work provides insight into DFT guidance for the design of D-A conjugated polymer and its application scenarios in photocatalytic decontamination.

Synthesis, and evaluation of photophysical properties of a potential DPP-derived photosensitizer for photodynamic therapy with D-A-D architecture

The study of a macromolecule derived from DPP and triphenylamine, (DPP-BisTPA) by computational chemistry, its synthesis by direct arylation, optical characterization (UV-Vis and fluorescence) and electrochemistry (cyclic voltammetry), as well as its evaluation as a generator of reactive oxygen species indirectly, through the degradation of uric acid. The results obtained by DFT using B3LYP/6-31G (d, p) and TD-DFT using CAM-B3LYP/6-31G (d, p) reveal values of energy levels of the first singlet and triplet excited state that indicate a possible intersystem crossover and the possible generation of reactive oxygen species by a type I mechanism. The compound presents an absorption region within the phototherapeutic window. The electrochemical bandgap is 1.64 eV which suggests a behavior as a semiconductor. DPP-BisTPa were processed as hemispherical nanoparticles with a size around 100 nm, and NPOs were evaluated as a photosensitizer with a ROS generation yield of 4% using a photodynamic therapy flashlight as the light source.

Recent Advances of Doping and Surface Modifying Carbon Nitride with Characterization Techniques

As a non-metallic organic semiconductor photocatalyst, graphitic carbon nitride (g–C3N4, CN) has become a research hotspot due to its excellent performance in organic degradation, CO2 reduction and water splitting to produce hydrogen. However, the high recombination rate of electron-hole pairs, low specific surface area and weak light absorption of bulk CN synthesized by the traditional one-step thermal polymerization method seriously restrict its photocatalytic performance and practical application. To enhance the photocatalytic performance of CN, doping and surface modification strategies are usually employed to tune the band gap of carbon nitride and improve the separation of carriers. In this paper, the research progress of different methods to modify CN in recent years is introduced, and the mechanisms of improving the photocatalytic performance are mainly analyzed. Typical modification methods are mainly divided into metal doping, non-metal doping, co-doping and surface-functionalized modification. Some characterization methods that can analyze the doping state and surface modification are also discussed as examples. Finally, the difficulties that need to be addressed through modified CN photocatalysts and the directions for future research are pointed out.

Incorporating Oxygen Atoms in a SnS2 Atomic Layer to Simultaneously Stabilize Atomic Hydrogen and Accelerate the Generation of Hydroxyl Radicals for Water Decontamination

Photoelectrocatalysis (PEC) is an efficient way to address various pollutants. Surface-adsorbed atomic hydrogen (H*) and hydroxyl radicals (•OH) play a key role in the PEC process. However, the instability of H* and low production of •OH considerably limit the PEC efficiency. In this study, we noted that incorporating oxygen atoms could regulate the behavior of H* by creating a locally favorable electron-rich state of S atoms in the SnS₂ catalyst. The finely modulated H* led to a 12-fold decrease in the overpotential of H₂O₂ generation (H*-OOH*-H₂O₂-•OH) by decreasing the activation energy barrier of OOH* (rate-determining step). Considering density functional theory calculations, an H*-•OH redox pair suitable for a wide pH range (3-11) was successfully constructed based on the photocathode. The optimal SnS_1.85O_0.15 AL@TNA photocathode exhibited a ∼90% reduction in Cr(VI) in 10 min and ∼70% TOC removal of 4-nitrophenol, nearly 2- and 3-fold higher than that without oxygen incorporation. Electron spin resonance spectrometry and radical quenching experiments verified that H* and the derived •OH via 1-electron and 3-electron reduction were the main active species. Operando Raman spectroscopy confirmed that the stable SnO₂ phase helped constantly activate the production of H* and •OH.

Donor–acceptor organic nanostructure based on conjugated polymer for improving visible-light-driven photocatalytic activity towards degradation of dye in aqueous medium

Hybrid donor–acceptor nanostructures based on P3HT with improved light harvesting properties were employed for organic dye degradation.

Constructing porous intramolecular donor–acceptor integrated carbon nitride doped with m-aminophenol for boosting photocatalytic degradation and hydrogen evolution activity

A porous intramolecular D–A integrated carbon nitride with boosted photocatalytic activity was constructed via thermal melting followed by thermal copolymerization of m-aminophenol with urea.