Electrophoretic Deposition of Co3O4 Particles/Reduced Graphene Oxide Composites for Efficient Non-Enzymatic H2O2 Sensing

In this work, the facile fabrication of Co₃O₄ particles/reduced graphene oxide (Co₃O₄/rGO) composites on Indium tin oxide (ITO) slide was achieved by an electrophoretic deposition and annealing process. The deposition time and ratio of the precursors were optimized. Structural characterization and chemical composition investigation indicated successful loading of Co₃O₄ particles on graphene sheets. When applied as a non-enzymatic H₂O₂ sensor, Co₃O₄/rGO showed significant electrocatalytic activity, with a wide linear range (0.1-19.5 mM) and high sensitivity (0.2247 mA mM^-1 cm^-2). The good anti-interference ability, reproducibility, and long-term stability of the constructed sensor were also presented. The application of Co₃O₄/rGO in real sample analysis was evaluated in human urine sample with satisfactory results, indicating the feasibility of the sensor in physiological and medical applications.

Excellent photocatalytic performances of Co3O4-AC nanocomposites for H2 production via wastewater splitting

Natural sunlight-driven photocatalytic hydrogen production from wastewater is one of the most desirable techniques that can realize future green energy technology. Herein, we report the synthesis and the characterization of the biomass activated carbon (AC)-decorated cobalt oxide (Co₃O₄) nanocomposites for solar-stimulated photocatalytic hydrogen production from sulphide wastewater. The Co₃O₄-AC nanocomposites were ultrasonically synthesized by using hydrothermally-grown spinel Co₃O₄ nanoflakes and biomass-derived AC nanoflakes. Co₃O₄-AC showed a nanobundle-like aggregated morphology, and exhibited a large specific surface area (~133 m²/g). Through utilizing Co₃O₄-AC as a photocatalyst for photocatalytic splitting of sulphide wastewater (0.2 M) under solar irradiance with 730 W/m², an enhanced H₂ production efficiency (~70 mL/h) was achieved owing to the synergic effects from 2-dimentionally configured Co₃O₄ and AC microstructures; i.e., large surface area of Co₃O₄ and high electrical conductivity of AC. These findings suggest the nanocomposites of Co₃O₄-AC to hold great promise for the green approach of photocatalytic wastewater splitting.

Electrophoretic Deposition for Lithium-Ion Battery Electrode Manufacture

Electrophoretic deposition (EPD) has received increasing attention as an alternative manufacturing approach to slurry casting for the production of battery and supercapacitor electrodes. This process is of relevance for industrial scalability as evidently seen in the current electrophoretic paints industry. Nevertheless, the reported work so far have only concentrated on thin films of electrophoretically deposited electrodes for energy storage. Here, the electrochemical performance of thick films (up to tens of μm) as lithium-ion battery electrodes produced by EPD is reported. A commercially sourced LiN1/3M1/3C1/3O2 (5 to 25 μm particle size) was used in this exemplary investigation. This work shows the production of binder-free high density active material (>90 %) electrodes. Coin cells were assembled and the battery performance was measured. Tests included: cyclic voltammetry, C-rate vs capacity, battery cycling and electrochemical impedance spectroscopy. Other investigations also studied: colloidal electrolyte formulation, electrode manufacture, microstructure characterisation and elemental mapping analysis. In short, EPD electrode manufacture can be applied as a platform technology for any battery and supercapacitor material, and the reported manufacturing processes and methodologies represent direct relevance to produce energy storage electrodes useful to practical applications.

Preparation and evaluation of the microwave absorption properties of template-free graphene foam-supported Ni nanoparticles

This study aims to explore superior microwave absorption properties using magnetic Ni nanoparticles to decorate a three-dimensional graphene foam.

Electrophoretic Deposition of SnFe2O4–Graphene Hybrid Films as Anodes for Lithium Ion Batteries

Binder-free SnFe2O4–submillimetre (hundreds of micrometres)-sized reduced graphene oxide (SnFe2O4–srGO) hybrid films were synthesized through electrophoretic deposition and subsequent carbonization treatment. Scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy results revealed that SnFe2O4–srGO hybrid films exhibit both horizontal and vertical channels. SnFe2O4–srGO hybrid films were used as binder-free anodes for lithium ion half-cells and revealed a high capacity of ~1018.5 mA h g−1 at 0.1 A g−1 after 200 cycles. During rate performance tests, a high capacity of 464.1 mA h g−1 (~61.2 % retention) was maintained at a current density of 4 A g−1, indicating an excellent structural stability of SnFe2O4–srGO hybrid films at high current densities.

Facile fabrication of highly porous Co3O4 nanobelts as anode materials for lithium-ion batteries

Highly porous Co₃O₄ nanobelts were successfully synthesized by using a hydrothermal technique, followed by calcination of the Co(OH)₂ precursor.