Embellishing hierarchical 3D core-shell nanosheet arrays of ZnFe2O4@NiMoO4 onto rGO-Ni foam as a binder-free electrode for asymmetric supercapacitors with excellent electrochemical performance

Engineering Lattice Strain in Co-Doped NiMoO4 for boosting Methanol Oxidation Reaction

Nickel-based molybdates have attracted considerable attention owing to their distinctive isomorphous structure. In this study, pristine NiMoO4 and Co-doped Ni1-xCoxMoO4 were synthesized and investigated for their electrocatalytic activity in methanol oxidation and methanol-assisted water splitting reactions. Through a comprehensive exploration of the structure-property relationship, it was found that the optimal coexistence of α and β molybdate phases, induced by Co doping, led to lattice strain and facilitated the presence of essential catalytic descriptors such as higher oxidation states of Ni and surface oxygen vacancies within the lattice. These factors contributed to the enhanced electrocatalytic activity of Ni0.7Co0.3MoO4 in methanol oxidation and hydrogen evolution reaction. Detailed kinetic studies were conducted to further elucidate the mechanisms involved. Overall, these findings highlight the promising potential of Ni0.7Co0.3MoO4 as an effective catalyst for electrochemical methanol upgrading in conjunction with water splitting, with implications for sustainable energy conversion technologies.

In situ growth of binder-free CoNi0.5-MOF/CC electrode for high-performance flexible solid-state supercapacitor application

Metal organic frameworks (MOFs) with binder-free electrodes have shown promise for portable electrochemical energy storage applications. However, their low specific capacitance and challenges associated with the attachment of active materials to the substrate constrain their practical utility. In this research, we prepared a CoNi0.5-MOF/CC electrode by in situ growth of CoNi0.5-MOF on an H2O2-pretreated carbon cloth (CC) without using any binder. It exhibits a higher specific capacitance of 1337.5 F g-1 than that of CoNi0.5-MOF (∼578 F g-1) at a current density of 1 A g-1 and an excellent rate ability of 88% specific capacitance retention at a current density of 10 A g-1 after 6000 cycles. The as-assembled flexible asymmetric solid-state supercapacitor based on the CoNi0.5-MOF/CC positive electrode and a nitrogen-doped graphene (N-Gr) negative electrode exhibits an energy density of 61.46 W h kg-1 at a power density of 1244.56 W kg-1 and holds a stable capacitance of ∼125 F g-1 at 1 A g-1 when the flexible supercapacitor is bent, showing great potential for flexible electronics application. The H2O2 is indicated to play an important role, enhancing the adhesion of CoNi0.5-MOF on CC and reducing its charge transfer resistance by functionalizing the carbon fiber during the pretreatment of the CC matrix. The results provide a great way to prepare a flexible asymmetric solid-state supercapacitor with both high power density and high energy density for practical application.

Heterostructured ZnFe2O4@Ni3S2 nanosheet arrays on Ni foam as an efficient oxygen evolution catalyst

Honeycomb-like ZnFe2O4@Ni3S2 hierarchical nanosheet arrays on Ni foam (NF) were fabricated via a combined hydrothermal and electrodeposition method. The electrode exhibits high oxygen evolution reaction (OER) activity with low overpotentials of 254 mV at 10 mA cm-2 and 290 mV at 50 mA cm-2, a small Tafel slope of 39.29 mV dec-1 and excellent durability in an alkaline electrolyte.

Bifunctional bimetallic oxide nanowires for high-efficiency electrosynthesis of 2,5-furandicarboxylic acid and ammonia

It is an appealing avenue for electrosyntheis of high-valued chemicals at both anode and cathode by coupling 5-hydroxymethylfurfural (HMF) oxidation and nitrate reduction reactions simultaneously, while the development such bifunctional electrocatalysts is still in its infancy with dissatisfied selectivity and low yield rate. Here, we first report that Zn-doped Co3O4 nanowires array can be served as an efficient and robust dual-functional catalyst for HMF oxidation and nitrate reduction at ambient conditions. Specifically, the catalyst shows a faradaic efficiency of 91 % and a yield rate of 241.2 μmol h-1 cm-2 for 2,5-furandicarboxylic acid formation together with a high conversion of nearly 100 % at a potential of 1.40 V. It also displays good cycling stability. Besides, the catalyst is capable of catalyzing the reduction of nitrate to NH3, giving a maximal faradaic efficiency of 92 % and a peak NH3 yield rate of 4.65 mg h-1 cm-2 at a potential of -0.70 V. These results surpass those obtained using pristine Co3O4 and are comparable to those of state-of-the-art electrocatalysts. Moreover, the catalyst is further employed as the cathode catalyst to assemble a Zn-nitrate battery, giving a peak power density of 5.24 mW cm-2 and a high yield rate of 0.72 mg h-1 cm-2. Theoretical simulations further reveal that Zn-doping favors the adsorption and dissociation of nitrate and HMF species and reduces the energy barrier as well. Our work demonstrates the potential interest of Co3O4-based materials for the highly selective production of valuable feedstocks via ambient electrolysis.

Copper nanoparticles/polyaniline/molybdenum disulfide composite as a nonenzymatic electrochemical glucose sensor

A Cu@Pani/MoS2 nanocomposite was successfully synthesized via combined in-situ oxidative polymerization and hydrothermal reaction and applied to an electrochemical nonenzymatic glucose sensor. The morphology of the prepared Cu@Pani/MoS2 nanocomposite was characterized using FE-SEM and Cs-STEM, and electrochemical analysis was performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry techniques. Electrostatic interaction between Cu@Pani and MoS2 greatly enhanced the charge dispersion, electrical conductivity, and stability, resulting in excellent electrochemical performance. The Cu@Pani/MoS2 was used as an electrocatalyst to detect glucose in an alkaline medium. The proposed glucose sensor exhibited a sensitivity, detection limit, and wide linear range of 69.82 μAmM-1cm-2, 1.78 μM, and 0.1-11 mM, respectively. The stability and selectivity of the Cu@Pani/MoS2 composite for glucose compared to that of the potential interfering species, as well as its ability to determine the glucose concentration in diluted human serum samples at a high recovery percentage, demonstrated its viability as a nonenzymatic glucose sensor.

Metal-Organic Framework Composites and Their Derivatives as Efficient Electrodes for Energy Storage Applications: Recent Progress and Future Perspectives

Metal-organic frameworks (MOFs) have been important electrochemical energy storage (EES) materials because of their rich species, large specific surface area, high porosity and rich active sites. Nevertheless, the poor conductivity, low mechanical and electrochemical stability of pristine MOFs have hindered their further applications. Although single component MOF derivatives have higher conductivity, self-aggregation often occurs during preparation. Composite design can overcome the shortcomings of MOFs and derivatives and create synergistic effects, resulting in improved electrochemical properties for EES. In this review, recent applications of MOF composites and derivatives as electrodes in different types of batteries and supercapacitors are critically discussed. The advantages, challenges, and future perspectives of MOF composites and derivatives have been given. This review may guide the development of high-performance MOF composites and derivatives in the field of EES.

Silicon Carbide Nanostructures as Potential Carbide Material for Electrochemical Supercapacitors: A Review

Silicon carbide (SiC) is a very promising carbide material with various applications such as electrochemical supercapacitors, photocatalysis, microwave absorption, field-effect transistors, and sensors. Due to its enticing advantages of high thermal stability, outstanding chemical stability, high thermal conductivity, and excellent mechanical behavior, it is used as a potential candidate in various fields such as supercapacitors, water-splitting, photocatalysis, biomedical, sensors, and so on. This review mainly describes the various synthesis techniques of nanostructured SiC (0D, 1D, 2D, and 3D) and its properties. Thereafter, the ongoing research trends in electrochemical supercapacitor electrodes are fully excavated. Finally, the outlook of future research directions, key obstacles, and possible solutions are emphasized.

Structural formation of multifunctional NiMoO4 nanorods for thermoelectric applications

We report on the synthesis and characterization of NiMoO4 (NMO) nanorods via the hydrothermal method.