Herein, we demonstrate the fabrication of highly capacitive activated carbon (AC) using a bio-waste Kusha grass (Desmostachya bipinnata), by employing a chemical process followed by activation through KOH. The as-synthesized few-layered activated carbon has been confirmed through X-ray powder diffraction, transmission electron microscopy, and Raman spectroscopy techniques. The chemical environment of the as-prepared sample has been accessed through FTIR and UV–visible spectroscopy. The surface area and porosity of the as-synthesized material have been accessed through the Brunauer–Emmett–Teller method. All the electrochemical measurements have been performed through cyclic voltammetry and galvanometric charging/discharging (GCD) method, but primarily, we focus on GCD due to the accuracy of the technique. Moreover, the as-synthesized AC material shows a maximum specific capacitance as 218 F g−1 in the potential window ranging from − 0.35 to + 0.45 V. Also, the AC exhibits an excellent energy density of ~ 19.3 Wh kg−1 and power density of ~ 277.92 W kg−1, respectively, in the same operating potential window. It has also shown very good capacitance retention capability even after 5000th cycles. The fabricated supercapacitor shows a good energy density and power density, respectively, and good retention in capacitance at remarkably higher charging/discharging rates with excellent cycling stability. Henceforth, bio-waste Kusha grass-derived activated carbon (DP-AC) shows good promise and can be applied in supercapacitor applications due to its outstanding electrochemical properties. Herein, we envision that our results illustrate a simple and innovative approach to synthesize a bio-waste Kusha grass-derived activated carbon (DP-AC) as an emerging supercapacitor electrode material and widen its practical application in electrochemical energy storage fields.

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Reduced-graphene-oxide layers (rGO) offer extremely subtle transducer thin-films and can be unified in interdigital microelectrodes for various purposes. Understanding the functions and nature of rGO specially bio-compatibility, we can use this as potent-tool for the detection of antibiotic-drug Rifampicin (RFP) in standard/pharmaceutical samples. Herein, we synthesize CuO@rGO nano-composite and explored its potency for the preparation of electrochemically-active-electrodes. Catalytic-activity of as-synthesized CuO@rGO nano-composite is checked in 1.0 mM of Fe 2 + /3 + solutions and found to be more than three times higher current as compared to bare, rGO or CuO modified GCE. Subsequently, modified electrodes are used to detect RFP via two-techniques (differential-pulse voltammetry viz. DPV and cyclic-voltammetry viz. CV) in three-ways simultaneously.

Schematic representation of the oxidation reaction mechanism of cefixime on the MoS2 QD–AuNP-modified SPCE and the corresponding DPV curve.