The design of highly efficient, durable, and earth-abundant catalysts for the oxygen evolution reaction is crucial to a variety of important energy conversion and storage processes. Here, we use carbon quantum dots (CQDs, ∼5 nm) to form hybrids with the ultrathin nickel-iron layered double-hydroxide (NiFe-LDH) nanoplates. The resulting CQD/NiFe-LDH complex exhibits high electrocatalytic activity (with an overpotential of ∼235 mV in 1 M KOH at a current density of 10 mA cm(-2)) and stability for oxygen evolution, which almost exceed the values of all previously reported Ni-Fe compounds and were comparable to those of the most active perovskite-based catalyst.

High-efficiency and high-selectivity catalytic oxidation of alkanes under mild conditions is a major objective of current catalysis chemistry and chemical production. Despite extensive development efforts on new catalysts for cyclohexane oxidation, current commercial processes still suffer from low conversion, poor selectivity, and excessive production of waste. We demonstrate the design and synthesis of composites made from metal nanoparticles and carbon quantum dots (CQDs) for high-efficiency and high-selectivity photocatalyst systems for the green oxidation of cyclohexane. Remarkably, the present Au nanoparticles/CQDs composite photocatalyst yields 63.8% conversion efficiency and 99.9% selectivity for the green oxidation of cyclohexane to cyclohexanone, using H2O2 under visible light at room temperature. Given its diversity and versatility of structural and composition design, metal nanoparticles/CQDs composites may provide a powerful pathway for the development of high-performance catalysts and production processes for green chemical industry.

Selective oxidation of alcohols is a fundamental and significant transformation for the large-scale production of fine chemicals, UV and visible light driven photocatalytic systems for alcohol oxidation have been developed, however, the long wavelength near infrared (NIR) and infrared (IR) light have not yet fully utilized by the present photocatalytic systems. Herein, we reported carbon quantum dots (CQDs) can function as an effective near infrared (NIR) light driven photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde. Based on the NIR light driven photo-induced electron transfer property and its photocatalytic activity for H2O2 decomposition, this metal-free catalyst could realize the transformation from benzyl alcohol to benzaldehyde with high selectivity (100%) and conversion (92%) under NIR light irradiation. HO˙ is the main active oxygen specie in benzyl alcohol selective oxidative reaction confirmed by terephthalic acid photoluminescence probing assay (TA-PL), selecting toluene as the substrate. Such metal-free photocatalytic system also selectively converts other alcohol substrates to their corresponding aldehydes with high conversion, demonstrating a potential application of accessing traditional alcohol oxidation chemistry.

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On the basis of the Jablonski diagram, the photophysical properties of optical agents are highly associated with biomedical function and efficacy. Herein, the focus is on organic/polymer optical agents and the recent progress in the main strategies for regulating their photophysical properties to achieve superior cancer diagnosis/phototheranostics applications are highlighted. Both the approaches of nanoengineering and molecular design, which can lead to optimized effectiveness of required biomedical function, are discussed.

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Carbon quantum dots (CQDs) were synthesized by an electrochemical etching method. The CQDs are well-dispersed with uniform size about 5 nm. FT-IR spectra suggest the presence of many hydroxyl groups on the surface of CQDs. Here, CQDs with diameter approximately 5 nm, directly used as effective heterogeneous nanocatalysts for Hbond catalysis in aldol condensations, show excellent photoenhanced catalytic ability (89% yields when 4-cyanobenzaldehyde is used). It demonstrated that aldol condensation between acetone and aromatic aldehydes resulted in higher yields with visible light irradiation than in the dark, confirming visible light is necessary for good conversion. The H-bond catalytic activities of CQDs can be significantly enhanced with visible light irradiation. The high catalytic activities of CQDs are due to highly efficient electron-accepting capabilities. Repeated catalytic experiments suggest that the CQD catalyst can be easily recycled as a heterogeneous catalyst with a long catalyst life.

A one-for-all organic agent for integrated triple-modality imaging-guided cancer surgery has been developed, in which the fluorescence, photoacoustic (PA), and Raman properties could be precisely tuned and boosted by tuning the molecular structure and intramolecular motions. By taking advantage of the merits of each mode, the organic nanoagent helps to decipher tumor information at different surgical stages and improve cancer surgery outcomes significantly. The preoperative fluorescence and PA imaging provide comprehensive information about tumors, while intraoperative fluorescence and Raman imaging accurately delineate tiny residual tumors.