Fluorescent carbon dots (CDs) are a novel type of fluorescent nanomaterials, which not only possess the specific quantum confinement effects of nanomaterials due to the small size of nanomaterials, but also have good biocompatibility and high fluorescence. Meanwhile, fluorescence CDs overcome the shortcomings of high toxicity of traditional nanomaterials. Moreover, the preparation procedure of fluorescent CDs is simple and easy. Therefore, fluorescent CDs have great potential applied in photocatalysis, biochemical sensing, bioimaging, drug delivery, and other related areas. In this paper, recent hot researches on fluorescent CDs are reviewed and some problems in the progress of fluorescent CDs are also summarized. At last, a future outlook in this direction is presented.

2D covalent organic frameworks (2D COFs) have been recognized as a novel class of photoactive materials owing to their extended π‐electron conjugation and high chemical stabilities. Herein, a new covalent organic framework (Tph‐BDP) is facilely synthesized by using a porphyrin derivative and an organic dye BODIPY derivative (5,5‐difluoro‐2,8‐diformyl‐1,3,7,9‐tetramethyl‐10‐phenyl‐5H‐dipyrrolo[1,2‐c:2′,1′‐f][1,3,2]diazabori‐nin‐4‐ium‐5‐uide) as monomers for the first time, and their unique photosensitive properties endow them excellent simulated oxidase activity under 635 nm laser irradiation that can catalyze the oxidation of 3,3′,5,5′‐tetramethylbenzidine (TMB). Further findings demonstrate that the presence of uranium (UO22+) can coordinate with imines of the oxidation products of TMB, thus modulating the charge transfer process of the colored products accompanied with intensive aggregation and remarkable color fading. This research provides a preparation strategy for COFs with excellent photocatalytic properties and nanozyme activity, and broadens the applications of the simple colorimetric methods for sensitive and selective radionuclide detection.

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In this work, we synthesized a two-dimensional fluorescent covalent–organic framework (TFPB–TTA COF) nanosheet by selecting and designing reactive monomers to realize the dual-functional processing of nitrophenols. The staggered benzene ring, triazine structure, and imine bond (CN) of the TFPB–TTA COF can capture free nitrophenols through hydrogen bonding and conjugation interaction, and then, the photoinduced electron transfer and fluorescence resonance energy transfer (FRET) between the TFPB–TTA COF and nitrophenols affects the fluorescence emission of the TFPB–TTA COF, realizing the fluorescence sensing of nitrophenols. The large K sv values and the low detection limit suggest that the TFPB–TTA COF can serve as sensitive and selective fluorescence sensors for nitrophenol detection in an aqueous system. At the same time, the strong interaction combined with the porous network structure of the TFPB–TTA COF facilitates the efficient adsorption and removal of nitrophenols. Especially for 2,4,6-trinitrophenol, the maximum adsorption capacity can reach 1045.53 mg/g with good recyclability and high structural stability of the TFPB–TTA COF. This work proposed a simple synthetic method for the construction of a fluorescent COF platform for the sensitive determination and efficient adsorption of nitrophenols.

Bacterial infection causes serious threats to human life, especially with the appearance of antibiotic-resistant bacteria. Phototherapeutic approaches have become promising due to their noninvasiveness, few adverse effects, and high efficiency. Herein, a covalent organic framework (TAPP-BDP) with a conjugated donor–acceptor (D–A) structure has been constructed for efficient photoinduced bacteriostasis. Under the irradiation with a single near-infrared (NIR) light (λ = 808 nm), TAPP-BDP alone involves triple and synergistic bacterial inhibition based on the integration of photodynamic, photothermal, and peroxidase-like enzymatic activities. The unique D–A structure endows TAPP-BDP with a narrow energy band gap, improving its photodynamic and nanozyme activities to generate reactive oxygen species (ROS) to realize the broad-spectrum bactericidal activity. The extended π-conjugated skeleton of TAPP-BDP results in enhanced absorption in NIR, and the remarkable photothermal activity can increase the temperature up to 65 °C to cause efficient bacterial degeneration. TAPP-BDP shows excellent antibacterial efficiency against both Gram-negative and Gram-positive bacteria. Animal experiments further suggest that TAPP-BDP can effectively heal wounds infected with Staphylococcus aureus in living systems.

Amidoxime-functionalized hydrothermal carbon (AO-HTC) has been synthesized and applied to adsorb U(vi) from aqueous solutions, exhibiting a high selectivity above 60% for a wide pH range from 1.0 to 5.0.

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