Cerium oxide decorated on nickel hydroxide anchored on reduced graphene oxide (Ce-Ni(OH)2/rGO) composite with hexagonal structures were synthesized by facile hydrothermal method. Fourier transform infrared spectroscopy (FT-IR), highresolution transmission electron microscopy with selected area diffraction (HRTEM-SAED), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer– Emmett–Teller (BET) surface area analysis and electrochemical technology were used to characterize the composite. Due to its unique two-dimensional structures and synergistic effect among Ce2O3, Ni(OH)2 and rGO components indicated twodimensional hexagonal nano Ce-Ni(OH)2/rGO composite is promising electrode material for improved electrochemical H2O2 sensing application. From 50 to 800 μM, the H2O2 concentration was linearly proportional to the oxidation current, with a lower detection of limit of 10.5 μM (S/N = 3). The sensor has a higher sensitivity of 0.625 μA μM−1 cm− 2. In addition, the sensor demonstrated high selectivity, repeatability and stability. These findings proved the viability of the synthetic method and the potential of the composites as a H2O2 sensing option.

Herein, a new and generic strategy has been proposed to introduce uniformly distributed graphitic carbon into the nanostructured metal oxide. A facile and generic synthetic protocol has been proposed to introduce uniformly distributed conducting graphitic carbon into the Co3O4 nanoparticles ( Co3O4 NPs@graphitic carbon). The prepared Co3O4 NPs@graphitic carbon has been drop casted onto the portable screen-printed electrode (SPE) to realize its potential application in the individual and simultaneous quantification of toxic Pb(II) and Cd(II) ions present in aqueous solution. The proposed Co3O4 NPs@graphitic carbon-based electrochemical sensor exhibits a wide linear range from 0 to 120 ppb with limit of detection of 3.2 and 3.5 ppb towards the simultaneous detection of Pb(II) and Cd(II), which falls well below threshold limit prescribed by WHO.

This work describes the facile synthesis of silver nanoparticle-decorated zinc oxide nanocomposite through a simple glycol reduction method. The silver nanoparticle-decorated zinc oxide nanocomposite-based pencil graphite electrode has been validated as a perceptive electrochemical sensing podium towards nitrite. The morphology of the prepared nanocomposite has been characterized via specific spectroscopic and electrochemical techniques. The sensor exhibits a notable enhancement in the cyclic voltammetric response to nitrite oxidation at an ideal peak potential of 0.76 V in pH 6.0 acetate buffer. Under optimum conditions of nitrite directly expanded with their concentration in the range from 30 to 1400 μM with a detection limit of 14 μM.