Optimizing synergistic effects: creating oxygen vacancies in NiCoWO4via a solid-state grinding method for improved energy storage performance

To address the escalating demand for electrical energy, developing high-performance electrochemical energy storage materials is crucial. Metal oxides represent promising materials for high-energy-density supercapacitors. Among these materials, transition metal-based tungstates exhibit significantly enhanced electrical conductivity compared to pure oxides. However, their low inherent conductivity, restricted electrochemically active sites, significant volume expansion, lower capacity, and deprived cycling stability undermine their electrochemical properties. Herein, we synthesised an oxygen vacancy-enriched NiCoWO4 electrode by a simple solid-state, solvent-free grinding process using NaBH4. The Ov-NiCoWO4 electrode displays an impressive capacitance of 703.66 F g-1 at 1 A g-1 and exceptional cycling stability with 87% retention over 2000 cycles at 7 A g-1. This excellent performance is attributed to the oxygen vacancy in the Ov-NiCoWO4 material, which increases the electron carrier density, accelerates electron transportation, enhances the active surface area, and boosts the redox reactivity of the material. In the as-prepared real-life supercapacitor configuration of Ov-NiCoWO4//AC, a determined capacitance of 129.10 F g-1 at 1 A g-1 is achieved. Additionally, it exhibits an energy density of 37.699 W h kg-1 with a power density of 724.98 W kg-1, signifying exceptional performance. Furthermore, it maintains an impressive cycle life, retaining approximately 88.5% over 1000 cycles.

Synthesis of Fluoride-Substituted Layered Perovskites ZnMoO4 with an Enhanced Photocatalytic Activity

Oxyfluorides possess considerable attention for their multiple excellent properties, but the conventional high-temperature solid-state syntheses have seen bottlenecks in the synthesis of new compounds. Herein, we report a novel layered oxyfluoride ZnMoO4:F, which is prepared by a facile hydrothermal method using ZnF2 as the fluoride source. The fluoride anions are successfully introduced into the oxygen sublattice, which is confirmed by a combined analysis using XRD, STEM, and TGA techniques. The as-synthesized ZnMoO4:F has an absorption edge at around 550 nm, indicating a red shift of Eg to the visible region compared to the oxide counterpart. The layered oxyfluoride exhibits an enhanced photocatalytic active for hydrogen evolution under simulated sunlight (λ > 350 nm), and the activity of ZnMoO4:F (651.9 μmol g-1) was 2 times higher than that of ZnMoO4 (309.7 μmol g-1). Further electrochemical analysis has shown that the conduction band position plays a critical role in the high performances of ZnMoO4:F. This work sheds new light on the future design and synthesis of novel fluoride-doped materials for photocatalysis applications.

Synthesis of Transition-Metal-Doped Nanocatalysts with Antibacterial Capabilities Using a Complementary Green Method

A facile single-step wet chemical synthesis of a transition-metal-doped molybdate derivative was achieved via an Ocimum tenuiflorum extract-mediated green approach. The Synthesized nanomaterials of doped molybdate were characterized by optical and other spectroscopic techniques, which confirmed the size of nanocrystalline (~27.3 nm). The thermal stability of the nanomaterials confirmed through thermogravimetric analysis showed similarity with nanomaterials of Mn-ZnMoO₄. Moreover, the nanoparticles displayed a non-toxic nature and showed antibactericidal activity. The impact of doping was reflected in band gap measurements; undoped ZnMoO₄ showed relatively lower band gap in comparison to Mn-doped ZnMoO₄. In the presence of light, ZnMoO₄ nanomaterials a exhibited photocatalytic response to solochrome dark blue dye with a concentration of 50 ppm. OH^- and O₂*^- radicals also destroyed the blue color of the dye within 2 min and showed potential antibactericidal activity towards both Gram-positive and Gram-negative bacteria, representing a unique application of the green-synthesized nanocatalyst.

Design and enhanced anticorrosion performance of a Zn5Mo2O11·5H2O/h-BN nanocomposite with labyrinth of nanopores

Zinc molybdate (ZMO) is a safe and effective grafting material for anticorrosion. Herein, we reported the synthesis of ZMO/h-BN with the labyrinth of capillary pores owing to the in situ growth of ZMO on flake hexagonal boron nitride (h-BN) using the hydrothermal method. The special morphological structure provided a tortuous path for aggressive species to the steel substrate, which extended and blocked the transmission of aggressive species, enhancing the physical corrosion barrier performance. In addition, the capillary pores of ZMO contributed to the competitive adsorption of Cl^- in an electrolyte and reduced the diffusion of aggressive species, thus further delaying the corrosion process. Moreover, the capture of oxygen by forming a B-O bond with h-BN and the formation of a molybdate passive film are beneficial for the inhibition of cathodic and anodic reactions. As verified by electrochemical impedance spectroscopy (EIS), the anticorrosion performance of ZMO/h-BN coating increased by 49.58% and 130.72% compared with ZMO and epoxy resin (EP) coatings after immersing in a NaCl aqueous solution (3.50 wt%) for 72 h. This coating matrix provides an avenue for molybdate-based corrosion remediation.

CuCoNi–S anchored CoMoO4/MoO3 forming core–shell structure for high-performance asymmetric supercapacitors

CoMoO4/MoO3@CuCoNi–S is prepared by hydrothermal and electrodeposition methods. It offers promising supercapacitor properties.