Cadmium sulfide (CdS) quantum dots (QDs) were homogeneously embedded into chitosan (CTS), denoted as CdS@CTS, via an in situ hydrothermal method. The intact structure of the synthesized materials was preserved using freeze-drying. The materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, transmission electron microscopy, high-resolution TEM, scanning TEM, dispersive energy X-ray (EDX) for elemental analysis and mapping, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption isotherms, thermogravimetric analysis, UV–vis spectroscopy, and diffuse reflectance spectroscopy (DRS). The synthesis procedure offered CdS QDs of 1–7 nm (average particle size of 3.2 nm). The functional groups of CTS modulate the in situ growth of CdS QDs and prevent the agglomeration of CdS QDs, offering homogenous distribution inside CTS. CdS@CTS QDs can also be used for naked-eye detection of heavy metals with high selectivity toward copper (Cu²⁺) ions. The mechanism of interactions between Cu²⁺ ions and CdS@CTS QDs were further studied.

Despite all the progress made to enrich the existing bank of drugs used to treat and cure Alzheimer and cancer patients, there is still a need to research and develop new bioactive candidates with superior efficacy but minimal side effects. In this context, a new series of anti-butyrylcholinesterase (anti-BChE), anti-tyrosinase and cytotoxic succinimide linked quinaldine conjugates 3a-i was designed and synthesized starting from 8-hydroxyquinaldine. The condensation of quinoleine-hydrazide 2 with electrophilic species such as aromatic and nonaromatic anhydrides provided the new compounds 3a-i. These synthesized heterocycles were characterized by spectroscopic means (¹H NMR, ¹³C NMR and ESI-HRMS). Their anti-butyrylcholinesterase, anti-tyrosinase and cytotoxic (cervical cancer cell (HeLa) and lung cancer cell (A549)) activities have been evaluated in vitro. Compounds 3e and 3 g were found to be more anti-BChE than Galanthamine. Compounds 3d, 3e and 3 g exerted better anti-tyrosinase activity than kojic acid. Also, 3a, 3f and 3 g showed interesting cytotoxic potential towards HeLa cell lines. These results were supported by the molecular docking analysis (structure–activity relationship (SAR)) to estimate and discuss possible interactions between these derivatives and active sites of proteins butyrylcholinesterase (PDB: 4B0P), tyrosinase (PDB: 2Y9X) and cytotoxic (topoisomerase IIα enzyme (PDB: 5GWK)).

Metal-organic framework (MOFs) based photocatalysis has received great attention recently as a promising technology for sustainable environmental applications. Herein, hydrogen peroxide (H₂O₂) activation with a copper-based metal-organic framework-derived catalyst (CuO@C) was applied for the photodegradation of a widely used analgesic paracetamol drug (PCM) under an energy-efficient visible light-emitted diode (LED) as a light source for the first time. The incorporation of CuO@C with H₂O₂ offered a photo-Fenton-like reaction that accelerated the PCM photodegradation, where 95% of paracetamol was degraded in 60 min. Interestingly, a novel N-curve pH trend was observed due to an independent boost of the PCM degradation at extreme pH_i 9.9. The redeposition of Cu to the CuO@C surface is likely the critical mechanism for minimizing Cu leaching and maintaining good catalyst reusability. Eight intermediates were identified and two of them were newly reported. Surprisingly, no dimerization route was observed as previously reported in other processes. Additionally, a mineralization degree of 68% was achieved which proved the merit of the CuO@C/H₂O₂/visible LED process for practical applications. This work can provide new insights on the application of Cu-based MOFs as rationale candidates for the remediation of emerging contaminants in wastewater by H₂O₂ activation.

Pyrolysis of cobalt (Co)-based metal-organic frameworks (MOF) was used to synthesize Co₃O₄@N-doped C composites. The hierarchical porous structure of zeolitic imidazolate frameworks (ZIF-67) was synthesized using a triethylamine-assisted method in water and room temperature. ZIF-67 was used as a precursor for the synthesis of Co₃O₄@N-doped C. The material was characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and X-ray photoelectron microscope (XPS). The carbon content and hierarchical porous structure of ZIF-67 enhanced the electron and ion transport. As a result of these advantages, the Co₃O₄@N-doped C electrode demonstrated improved capacitive performance, with a high specific capacitance of 709 F g⁻¹ at 1 A g⁻¹ and a reasonable rate capability after 5000 cycles. The simple synthesis procedure and the high electrochemical performance enable promising electroactive materials for supercapacitors using MOF-derived materials.

The processing of hierarchical porous zeolitic imidazolate frameworks (ZIF-8) into a cellulose paper using sheet former Rapid-Köthen (R.K.) is reported. The procedure is a promising route to overcome a significant bottleneck towards applying metal-organic frameworks (MOFs) in commercial products. ZIF-8 crystals were integrated into cellulose pulp (CP) or TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-oxidized cellulose nanofibrils (TOCNF) following an in-situ or ex-situ process; the materials were denoted as CelloZIFPaper_In Situ and CelloZIFPaper_Ex Situ, respectively. The materials were applied as adsorbents to remove heavy metals from water, with adsorption capacities of 66.2–354.0 mg/g. CelloZIFPaper can also be used as a stand-alone working electrode for the selective sensing of toxic heavy metals, for instance, lead ions (Pb²⁺), using electrochemical-based methods with a limit of detection (LOD) of 8 µM. The electrochemical measurements may advance 'Lab-on-CelloZIFPaper' technologies for label-free detection of heavy metal ions.

Energy storage materials have advanced renewable energy technologies. Herein, we described the one-pot synthesis of covalent organic frameworks (COFs)/graphitic carbon nitride (g-C₃N₄) nanocomposite. The condensation of melamine and benzene-1,3,5-tricarboxyaldehyde with and without g-C₃N₄ offered the synthesis of COF and COF/g-C₃N₄. Furthermore, N-doped carbon and N-doped carbon/g-C₃N₄ were synthesized via the carbonization of COF and COF/g-C₃N₄, respectively. The materials i.e., before and after carbonization were used as electrode materials for supercapacitors and lithium-ion batteries (LIBs). They showed specific capacitance of 211, 257.5, 450, and 835.2 F·g^–1 for COF, COF/g-C₃N₄, N-doped carbon, and N-doped carbon/g-C₃N₄, respectively. Asymmetric supercapacitor device using N-doped carbon/g-C₃N₄ exhibited good energy (45.97 Wh·kg^–1) with high power (659.3 W·kg^–1). The N-doped C/g-C₃N₄ electrode was also applied for LIBs, offering a discharge capacity of 390 mAh·g^–1 (at 50 mA·g^–1).

Carbon dioxide (CO₂) is one of the culprit causes of global climatic changes. Furthermore, the efficient separation of CO₂ from other gaseous mixtures using zeolitic imidazolate framework (ZIF)-based materials is vital for several processes such as flue gas separation, gas sweetening, and natural gas processing. ZIF-based materials are emerging adsorbents and catalysts for CO₂ gas removal via adsorption and conversion into valuable chemicals. ZIF-based adsorbents with high-adsorption/conversion efficiencies and tunable properties can be achieved by judicious synthesis and fabrication methods. We reviewed ZIF-based materials for CO₂ removal via adsorption and catalysis (e.g., cycloaddition, carboxylation, hydrogenation, N-formylation, electrocatalysis, and photocatalysis). In addition, recent development methods such as membrane technologies and ways to improve the gas separation performance of ZIF membranes were highlighted. The prospective point of view to promote industrial applications and commercialization of ZIF-based materials was briefly discussed. Once challenges such as low performance and reproducibility for ZIF-based materials are solved, scalability and cost-effectiveness should not become issues.