Recent Advances in Co3O4-Based Composites: Synthesis and Application in Combustion of Methane

In recent years, it has been found that adjusting the organizational structure of Co₃O₄ through solid solution and other methods can effectively improve its catalytic performance for the oxidation of low concentration methane. Its catalytic activity is close to that of metal Pd, which is expected to replace costly noble metal catalysts. Therefore, the in-depth research on the mechanism and methods of Co₃O₄ microstructure regulation has very important academic value and economic benefits. In this paper, we reviewed the catalytic oxidation mechanism, microstructure regulation mechanism, and methods of nano-Co₃O₄ on methane gas, which provides reference for the development of high-activity Co₃O₄-based methane combustion catalysts. Through literature investigation, it is found that the surface energy state of nano-Co₃O₄ can be adjusted by loading of noble metals, resulting in the reduction of Co-O bond strength, thus accelerating the formation of reactive oxygen species chemical bonds, and improving its catalytic effect. Secondly, the use of metal oxides and non-metallic oxide carriers helps to disperse and stabilize cobalt ions, improve the structural elasticity of Co₃O₄, and ultimately improve its catalytic performance. In addition, the performance of the catalyst can be improved by adjusting the microstructure of the composite catalyst and optimizing the preparation process. In this review, we summarize the catalytic mechanism and microstructure regulation of nano-Co₃O₄ and its composite catalysts (embedded with noble metals or combined with metallic and nonmetallic oxides) for methane combustion. Notably, this review delves into the substance of measures that can be used to improve the catalytic performance of Co₃O₄, highlighting the constructive role of components in composite catalysts that can improve the catalytic capacity of Co₃O₄. Firstly, the research status of Co₃O₄ composite catalyst is reviewed in this paper. It is hoped that relevant researchers can get inspiration from this paper and develop high-activity Co₃O₄-based methane combustion catalyst.

Recent Advances on Synthesis of CoCO3 with Controlled Morphologies

Cobalt carbonates and derivatives represent most promising cost-effective materials for energy storage, conversion and upgrading. Morphology determines the performances, as size, shape and electronic configuration are key factors for tunable properties in the area of batteries, catalysis, magnetics and plasmonics. However, there is lack of insights in literature on morphological control of cobalt carbonates during hydrothermal and solvothermal conditions. Therefore, this review provides detailed discussion on synthesis, formation mechanism and morphological control of nanosheets, wires, spheres and cubes of cobalt carbonates. Furthermore, the influence of experimental conditions and plausible mechanism which govern the growing processes were further discussed in details. The outcome of this short review will offer insights into rational design of inexpensive metal carbonates for numerous other energy and environment applications.

Multi-layer-stacked Co9S8 micro/nanostructure directly anchoring on carbon cloth as a flexible electrode in supercapacitors

Rational design and synthesis of electrode materials containing uniformly stacked lamella structures with high surface areas are attractive for efficient storage of electrochemical energy. In this work, Co9S8 clusters with a uniformly stacked lamella structure was directly anchored onto carbon cloth (CC) by an easy-to-implement chemical solution processing method, which involves the homogeneous growth of the CoCO3 precursor, promoting the formation of nanosheets during the subsequent sulfurization process. Due to the conductive substrate (CC) and special multi-layer micro/nanostructure (Co9S8), the flexible Co9S8/CC electrode, which can be tailored, bent and twisted arbitrarily without affecting its electrochemical properties, also exhibits excellent electrochemical properties with a high specific capacitance (1475.4 F g-1 at 1 A g-1), a good rate capacity (80.2% retention at 20 A g-1) and excellent cycling stability (92.9% retention over 5000 cycles). In addition, the assembled solid-state asymmetric supercapacitor device containing the fabricated Co9S8 as the positive electrode and activated carbon as the negative electrode, also exhibits a high energy density of 20.3 W h kg-1 at a power density of 22 796.1 W kg-1 and a high energy density of 33.2 W h kg-1 at a power density of 817.9 W kg-1. Because of its good electrochemical properties and flexibility, the flexible Co9S8/CC electrode material is very promising to be used in flexible supercapacitors and wearable electronic technology.

Influence of Ni on enhanced catalytic activity of Cu/Co3O4 towards reduction of nitroaromatic compounds: studies on the reduction kinetics

Addition of Ni significantly enhances the reaction rates of Cu/Co₃O₄ for the catalytic reduction of nitroaromatic compounds.

Co3O4 nanocrystals derived from a zeolitic imidazolate framework on Ni foam as high-performance supercapacitor electrode material

A binder-free method was adopted to obtain a Ni foam/Co₃O₄ electrode.

Controllable synthesis of micro/nano-structured MnCo2O4 with multiporous core–shell architectures as high-performance anode materials for lithium-ion batteries

Various micro/nano-structured MnCo₂O₄ with excellent lithium storage performance were synthesized controllably.

Ligand-assisted soft-chemical synthesis of self-assembled different shaped mesoporous Co3O4: efficient visible light photocatalysts

Mesoporous self-assembled cobalt oxide (Co₃O₄) of different shapes was synthesized by a facile soft-chemical process using cobalt nitrate, oxalic acid and phosphoric acid in the presence of cationic templates, cetyltrimethylammonium bromide, 1-butyl-3-methylimidazolium bromide, and pyridinium bromide at 75 °C/2 h followed by calcination at 300 °C.

Synthesis of small Fe2O3 nanocubes and their enhanced water vapour adsorption–desorption properties

Uniform ordered Fe₂O₃ nanocubes showed an excellent humidity-controlling ability, due to their appropriate pore size distribution near the condensation critical radius.

Micro-/nanostructured Co3O4 anode with enhanced rate capability for lithium-ion batteries

Through a facile hydrothermal method with a special surfactant triethanolamine (TEA) followed by thermal treatment, monodispersed micro-/nanostructured Co3O4 powders with unique morphology (cube) have been synthesized successfully as anode material for Li-ion batteries (LIBs). The regular Co3O4 microcubes (∼2.37 μm in the average side length) consist of many irregular nanoparticles (20-200 nm in diameter, 30-40 nm in thickness) bonded to each other, which greatly inherit the morphology and size of the precursor CoCO3. The specific surface area of Co3O4 powders is about 5.10 m(2)·g(-1) by the Brunauer-Emmett-Teller (BET) method, and the average pore size is about 3.08 nm by the Barrett-Joyner-Halenda (BJH) method. In addition, the precursor is verified as a single-crystal, while the mesoporous cubic Co3O4 is a polycrystalline characteristic assembled by numerous single-crystal nanoparticles. More remarkable, the high performance of the micro-/nanostructured cubic Co3O4 powders has been obtained by the electrochemical measurements including high initial discharge capacities (1298 mAhg(-1) at 0.1 C and 1041 mAhg(-1) at 1 C), impressive rate capability, and excellent capacity retention (99.3%, 97.5%, 99.2%, and 89.9% of the first charge capacities after 60 cycles at 0.1 C, 0.2 C, 0.5 C, and 1 C, respectively).

A new synthetic route to hollow Co3O4 octahedra for supercapacitor applications

Hollow Co₃O₄ octahedra, synthesized through a new solvothermal method, exhibited a charge storage capacity of 192 F g⁻¹ with good long-term cyclability.