Pt as a chemical inert metal has been widely applied as the counter electrode in various electrochemical measurements. However, it can also be dissolved and redeposit to the working electrode under certain electrochemical circumstances. Herein we demonstrated a cyclic voltammetry (CV) cycling method to synthesize a catalyst comprising inserted Pt nanoparticles into MoS₂ nanoflake stack structures on stainless steel mesh (SSM). The binder-free composite structure exhibits significantly enhanced hydrogen evolution reaction (HER) catalytic activity with an overpotentials of 87 mV at 10 mA cm⁻². The deposited Pt nanoparticles significantly enhance the catalytic activity through changing the structure of MoS₂ and increasing the amount of active sites. This work provides a new way forward for rational design of the nano-electrocatalysts.

The main objective of the current discussion was to decorate the polypyrrole (PPy) supported with copper (Cu) nanoparticles on alkali anodized steel (AS) electrode for detection of glucose in human saliva and serum samples. Initially the steel was anodized in 10 M NaOH then electrodeposition method was applied for fabrication of CuNPs and PPy at room temperature. First time we prepared this sensor by simple alkaline anodized method. The as prepared electrode was represented as PPy/Cu/AS used as an electrochemical sensor. As usual cyclic voltammetry (CV), EIS, FESEM, energy dispersive spectroscopy (EDX) and X-ray diffraction (XRD) were used for the characterization and structure analysis of the prepared modified nano sensor (PPy/Cu/AS). The nano structure of the sensor outcomes reveals that Cu nanoparticles deposited on anodized steel (AS), a bunch of particles, like ball shape with the diameter of around 200-800 nm and further notably not including Fe, Cu, and no other elements were detected on the sensor. The prepared sensor exhibits a linear range of 0.1–10 mM (for saliva 1 mM) glucose with a limit of detection (LOD) of 0.45 μM (S=3α/a, α: standard deviation, a: slope) and sensitivity is calculated to be 37.11 μA mM−1 cm−2 using amperometry. Further significantly, the usual interfering agents such as ascorbic acid (AA), uric acid (UA), sucrose and fructose were rigorously evaded from the oxidation of glucose. The prepared modified biosensor discloses an enriched electrocatalytic possessions, good stability, good amperometric response, high sensitivity, superb selectivity and sensing regarding the oxidation of glucose. In consequence the modified sensor was good for the imminent growth of non-enzymatic biosensors. The as prepared sensor was successfully employed for detection of glucose (GLC) in human blood serum as well as saliva samples.

An electrochemical sensor based on a palladium (Pd) and graphene (Gr) composite modified glassy carbon electrode (GCE) was fabricated, characterised and used for the simultaneous determination of omethoate (OMT) and dichlorvos (DCV) in grain samples. The Pd/Gr/GCE was characterized by scanning electron microscopy (SEM) and cyclic voltammograms (CV). The modified electrode displayed a greatly improved voltammetric response to OMT and DCV. Square wave voltammetry (SWV) was used for the individual and simultaneous determination of OMT and DCV. Various conditions were optimized, such as the pH of the buffer, the applied sample volume, the accumulation potential, the accumulation time, the square wave frequency and the step potential. Well defined reduction (OMT at CO, DCV at CC) peaks were obtained over the potential maximum in an acidic medium in phosphate buffer solution at −0.50 V and −0.80 V for both OMT and DCV. Low current peaks were obtained over the concentration of 3.50 × 10⁻⁸ M with detection limits 2.47 × 10⁻¹⁰ M and 3.28 × 10⁻¹⁰ M for OMT and DCV respectively. The composite modified electrode showed good stability and reproducibility. Therefore, the proposed method was successfully applied as an economical and simple sensor with a shorter analysis time.