Electrocatalytic activity for proton reduction by a covalent non-metal graphene-fullerene hybrid

A non-metal covalent hybrid of fullerene and graphene was synthesized in one step via fluorographene chemistry. Its electrocatalytic performance for the hydrogen evolution reaction and durability was ascribed to intrahybrid charge-transfer phenomena, exploiting the electron-accepting properties of C-60 and the high conductivity and large surface area of graphene.Web of Science58608399839

Click and detect: Versatile ampicillin aptasensor enabled by click chemistry on a graphene-alkyne derivative

Tackling the current problem of antimicrobial resistance (AMR) requires fast, inexpensive, and effective methods for controlling and detecting antibiotics in diverse samples at the point of interest. Cost-effective, disposable, point-of care electrochemical biosensors are a particularly attractive option. However, there is a need for conductive and versatile carbon-based materials and inks that enable effective bioconjugation under mild conditions for the develop ment of robust, sensitive, and selective devices. This work describes a simple and fast methodology to construct an aptasensor based on a novel graphene derivative equipped with alkyne groups prepared via fluorographene chem istry. Using click chemistry, an aptamer is immobilized and used as a suc cessful platform for the selective determination of ampicillin in real samples in the presence of interfering molecules. The electrochemical aptasensor displayed a detection limit of 1.36 nM, high selectivity among other antibi otics, the storage stability of 4 weeks, and is effective in real samples. Addi tionally, structural and docking simulations of the aptamer shed light on the ampicillin binding mechanism. The versatility of this platform opens up wide possibilities for constructing a new class of aptasensor based on disposable screen-printed carbon electrodes usable in point-of-care devices.Web of Scienc

Carbon nanotube based metal-organic framework hybrids from fundamentals toward applications

Metal-organic frameworks (MOFs) materials constructed by the coordination chemistry of metal ions and organic ligands are important members of the crystalline materials family. Owing to their exceptional properties, for example, high porosity, tunable pore size, and large surface area, MOFs have been applied in several fields such as gas or liquid adsorbents, sensors, batteries, and supercapacitors. However, poor conductivity and low stability hamper their potential applications in several attractive fields such as energy and gas storage. The integration of MOFs with carbon nanotubes (CNTs), a well-established carbon allotrope that exhibits high conductivity and stability, has been proposed as an efficient strategy to overcome such limitations. By combining the advantages of MOFs and CNTs, a wide variety of composites can be prepared with properties superior to their parent materials. This review provides a comprehensive summary of the preparation of CNT@MOF composites and focuses on their recent applications in several important fields, such as water purification, gas storage and separation, sensing, electrocatalysis, and energy storage (supercapacitors and batteries). Future challenges and prospects for CNT@MOF composites are also discussed.Web of Science184art. no. 210462

All-Carbon Nanosized Hybrid Materials: Fluorescent Carbon Dots Conjugated to Multiwalled Carbon Nanotubes

Fluorescent carbon dots (CDs) were synthesized by following a hydrothermal route in which butane-1,4-diamine and maleic acid were employed in a Teflon autoclave reactor. The structure and morphology of the so-formed spherically shaped CDs were confirmed by a combination of spectroscopic and imaging techniques, such as NMR, ATR-IR, DLS, XRD, and HR-TEM. Additionally, it was found that raw CDs possess numerous −NH₂ functionalities located in their external periphery, responsible for their enhanced aqueous solubility as well as the excellent dissolution CDs showed in polar protic solvents. Moreover, these −NH₂ units were utilized for covalently associating CDs with oxidized multiwalled carbon nanotubes (MWCNTs) yielding robust CDs–MWCNTs hybrids. Based on photoluminescence spectroscopy, electronic communications between the individual components of CDs–MWCNTs were evidenced by the quantitative quenching of the emission of CDs in the presence of MWCNTs as well as the shortening of the photoluminescence lifetime of CDs from 7.3 ns for raw CDs to 300 ps for CDs–MWCNTs. Finally, the redox properties of CDs–MWCNTs were evaluated by electrochemistry measurements, allowing to determine the electrochemical band gap of the hybrid material to be 1.2 eV

Thermal and dielectric performance of ester oil-based pentyl-graphene nanofluids

This work reports on the significant enhancement of the thermal properties of the FR3 natural ester dielectric oil after the addition of pentyl-graphene nanosheets, as confirmed by thermal diffusivity and specific heat studies at different concentrations and temperatures (30 degrees C-90 degrees C). Experimental results of the dielectric constant demonstrated a constant value in the kHz region while increased in the low-frequency region, decreased with increased temperature, and saturated at 0.008% w/w concentration. In addition, light absorption is used for a better understanding of the properties variation upon changing graphene's concentration as a method to estimate the agglomeration level. The optimum concentration for its best performance in terms of thermal and dielectric properties is 0.008% w/w, whereby the thermal diffusivity and the dielectric constant increased by 43.04% and 6.18%, respectively.Web of Science29251851