In this paper, a facile one-step sucrose-nitrate decomposition method has been proposed to synthesis Mn 3 O 4 nanoparticles (Mns)/graphitic carbon. The prepared material has been characterized by X-ray diffraction, Fourier transform infrared spectrometer, surface area analysis and transmission electron microscopy. The prepared Mns/graphitic carbon is drop-casted on glassy carbon electrode to allow the fabrication of electrochemical sensors for the simultaneous detection of Pb(II), Cd(II) and Hg(II) at nanomolar (nM) levels in aqueous solutions via differential pulse anodic stripping voltammetry. The proposed Mns/graphitic carbon sensors exhibit a wide linear range from 20 to 680 nM towards the simultaneous sensing of Cd(II), Pb(II) and Hg(II), and the corresponding limits of detection were found to be 0.48 9 10 -11 , 9.66 9 10 -11 and 0.51 9 10 -11 M, respectively. The practical application of the proposed sensor is evaluated within a real battery, industrial and chrome plating effluents.

The development of high-capacity anodes that are stable at high rates is of immediate interest as a potential alternative to the commercial graphite anode in lithium-ion batteries (LIBs). Conversion-based transition metal oxides, known for their high theoretical capacities, have been extensively studied in this regard. In this work, a ternary FeOOH-rGO-MnO2 composite has been suitably designed to address the limitations of the bare FeOOH anode arising from poor conductivity and volume expansion. A simple low-temperature synthesis method was employed to obtain a uniform distribution of FeOOH nanorods over the rGO matrix, which was further modified with a buffer layer of amorphous MnO2 nanosheets. While cycling at high rates, the modified composite anode delivered capacities of 956, 842, and 688 mAh g–1 at 1, 2, and 5 A g–1, respectively, for 200 cycles along with a cycling stability of 900 mAh g–1 at 1 A g–1 for 100 cycles. Various electrochemical techniques were used to analyze the superior performance of the ternary composite anode. The carbon matrix effectively provides favorable pathways for electron conduction and aids in the stable SEI formation, while the amorphous MnO2 sustains the structural integrity of the electrode by controlling volume expansion. Further, the exceptional stability of the anode at high rates was attributed to the marked increase in capacitive contribution in the FeOOH-rGO-MnO2 ternary composite anode, paving the way for faster electrode kinetics.

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<p>Hexagonal tungsten trioxide (h-WO3) nanoflakes have been synthesized by a hydrothermal approach using L-lysine as the shape directing agent. The influence of hydrothermal reaction time and L-lysine content on the morphology of h-WO3 was investigated. The experimental results showed that the nanoflake morphology could be achieved at higher concentration of L-lysine. Based on the evolution of nanoflake morphology as a function of hydro-thermal duration, a “dissolution-crystallization-Ostwald ripening” growth mechanism has been proposed. The electro-chemical performance of h-WO3 nanoflakes has also been investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that h-WO3 modified glassy carbon electrode (GCE) showed lower charge transfer resistance and enhancement in peak current attributed to the enrichment in electroactive surface area and faster electron transfer kinetics at h-WO3 modified GCE.</p>