Over the present material synthesis routes, the sonochemical route is highly efficient and comfortable way to produce nanostructured materials. In this way, the copper sulfide (CuS-covellite) and sulfur doped reduced graphene oxide (S-rGO) nanocomposite was prepared by sonochemical method. Interestingly, the structure of the as-prepared S-rGO/CuS was changed from the covellite to digenite phase. Herein, the S-rGO was act as a mild oxidizer and liable for the structural transformations. These structural changes are sequentially studied by various physicochemical characterizations such as Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM). After scrupulous structural evaluations, the transformation of CuS phase was identified and documented. This oxidized CuS has an excellent electrocatalytic activity when compare to the bulk CuS. This S-rGO/CuS was further used for the determination of glucose and acquired good electrocatalytic performances. This S-rGO/CuS was exhibited a wide linear concentration range, 0.0001–3.88 mM and 3.88–20.17 mM, and a low-level detection limit of 32 nM. Moreover, we have validated the practicability of our developed glucose sensor in real biological samples.

As a growing aspect of materials science, there are an enormous number of synthesis routes that have been identified to produce materials, particularly through simple methodologies. In this way, the present study focuses on the easiest way to prepare sulfur doped carbon nanoparticles (SDCNs) using a flame synthesis method and has also demonstrated a novel route to synthesize Ni(OH)2 decorated SDCNs by a simple adsorption cum precipitation method. The SDCNs are alternative candidates to prestigious carbon materials such as graphene, carbon nanotubes, and fullerenes. Moreover, SDCNs provide excellent support to the Ni(2+) ion adsorption and initiate the formation of Ni(OH)2. The formation of Ni(OH)2 on the SDCN matrix was confirmed by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), selected area diffraction pattern (SAED), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). After these meticulous structural evaluations, we have described the mechanism for the formation of Ni(OH)2 on an SDCN matrix. The as-prepared Ni(OH)2 decorated SDCN nanocomposites were used as an electrode material for nonenzymatic glucose sensors. The fabricated glucose sensor exhibited a wide linear concentration range, 0.0001-5.22 mM and 5.22-10.22 mM, and a low-level detection limit of 28 nM. Additionally, it reveals excellent selectivity in the potentially interfering ions and also possesses a good stability. The practicality of the fabricated glucose sensor was also demonstrated toward glucose detection in biological samples.

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We reported an electrochemical determination of caffeic acid (CA) based on the nitrogen doped carbon (NDC). The described sensor material was prepared by the flame synthesis method, which gave an excellent platform for the synthesis of carbon nanomaterials with the hetero atom dopant. The synthesized material was confirmed by various physical characterizations and it was further characterized by different electrochemical experiments. The NDC modified glassy carbon electrode (NDC/GCE) shows the superior electrocatalytic performance towards the determination of CA with the wide linear concentration range from 0.01 to 350 μM. It achieves the lowest detection limit of 0.0024 μM and the limit of quantification of 0.004 μM. The NDC/GCE-CA sensor reveals the good selectivity, stability, sensitivity and reproducibility which endorsed that the NDC is promising electrode for the determination of CA. In addition, NDC modified electrode is applied to the determination of CA in red wines and acquired good results.

Sodium-ion hybrid supercapacitors are potential energy-storage devices and have recently received enormous interest. However, the development of cathode materials and the use of nonaqueous electrolyte remain a great challenge. Hence, aqueous Na-ion hybrid supercapacitors based on a three-dimensional network of NaMnO were developed. The cathode material was synthesized by the electro-oxidation of potassium manganese hexacyanoferrate nanocubes. The oxidized compound was confirmed to be Na MnO by various physical characterization methods. Manganese dioxide is a well-characterized material for aqueous asymmetric pseudocapacitors, but its usage at high operating voltages is limited due to the electrochemical stability of water. Nevertheless, high-potential and high-performance aqueous supercapacitors exhibiting a cell potential of 2.7 V were developed. Further, the practical applicability of an asymmetric supercapacitor based on NaMnO (cathode) and reduced graphene oxide (anode) was demonstrated by powering a 2.1 V red LED.