Unique multi-phase Co/Fe/CoFe 2 O 4 by water–gas shift reaction, CO oxidation and enhanced supercapacitor performances

Energy Storage and CO2 Reduction Performances of Co/Co2C/C Prepared by an Anaerobic Ethanol Oxidation Reaction Using Sacrificial SnO2

Co/Co2C/C hybrids were prepared employing a new synthetic route and demonstrated as materials for energy storage and CO2 recycling application. Herein, an anaerobic ethanol oxidation reaction over Co3O4 nanoparticles (NPs) was first employed to fabricate Co/Co2C/C hybrids using sacrificial SnO2. In the absence of SnO2, Co3O4 NPs were converted to alpha and beta metallic Co. On the other hand, using sacrificial SnO2 resulted in the formation of Co2C and Co embedded in the carbon matrix at approximately 450 °C, as determined by temperature-programmed mass spectrometry analysis. The newly developed materials were fully examined by X-ray diffraction crystallography, scanning electron microscopy, energy-dispersive X-ray analysis, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The Co/Co2C/C hybrids showed a specific capacitance of 153 F/g at a current density of 0.5 A/g. Photocatalytic CO2 reduction experiments were performed and generated CO, CH4, and CH3OH as reduction products with yields of 47.7, 11.0, and 23.4 μmol/g, respectively. The anaerobic ethanol oxidation reaction could be a very useful method for the development of carbon-supported metal carbides, which have not been achieved by other synthetic methods. Furthermore, the demonstration tests unveiled new application areas of Co carbide materials.

Controllable synthesis of CoFe2O4 electrospun nanofibers

Controllable synthesis of CoFe₂O₄ nanofibers has been realized by controlling the electrospinning process parameters.

Electrodeposited Nanostructured CoFe2O4 for Overall Water Splitting and Supercapacitor Applications

To contribute to solving global energy problems, a multifunctional CoFe2O4 spinel was synthesized and used as a catalyst for overall water splitting and as an electrode material for supercapacitors. The ultra-fast one-step electrodeposition of CoFe2O4 over conducting substrates provides an economic pathway to high-performance energy devices. Electrodeposited CoFe2O4 on Ni-foam showed a low overpotential of 270 mV and a Tafel slope of 31 mV/dec. The results indicated a higher conductivity for electrodeposited compared with dip-coated CoFe2O4 with enhanced device performance. Moreover, bending and chronoamperometry studies suggest excellent durability of the catalytic electrode for long-term use. The energy storage behavior of CoFe2O4 showed high specific capacitance of 768 F/g at a current density of 0.5 A/g and maintained about 80% retention after 10,000 cycles. These results demonstrate the competitiveness and multifunctional applicability of the CoFe2O4 spinel to be used for energy generation and storage devices.

Cu-Based mixed metal oxides for an efficient photothermal catalysis of the water-gas shift reaction

Cu–ZnO catalyst with a well-designed nanojunction structure was fabricated for the photothermal catalysis of the water-gas shift (WGS) reaction.

Ni/NiM2O4 (M = Mn or Fe) supported on N-doped carbon nanotubes as trifunctional electrocatalysts for ORR, OER and HER

The NCNT/Ni–NiM₂O₄ (M = Mn or Fe) exhibit excellent trifunctional electrocatalytic performance for ORR, OER and HER.

Synthesis of cobalt ferrite nanoparticles by constant pH co-precipitation and their high catalytic activity in CO oxidation

A series of cobalt ferrite samples were synthesized from a metal nitrate solution at constant pH between 9 and 12 by the controlled co-precipitation method without any surfactant.

Sulfur-doped CoFe2O4 nanopowders for enhanced visible-light photocatalytic activity and magnetic properties

Magnetic recovery S-CoFe₂O₄ nanopowders showed excellent visible photocatalytic degradation of oxytetracycline and recycling performances in aqueous solution.

Application of Ni-Oxide@TiO₂ Core-Shell Structures to Photocatalytic Mixed Dye Degradation, CO Oxidation, and Supercapacitors

Performing diverse application tests on synthesized metal oxides is critical for identifying suitable application areas based on the material performances. In the present study, Ni-oxide@TiO₂ core-shell materials were synthesized and applied to photocatalytic mixed dye (methyl orange + rhodamine + methylene blue) degradation under ultraviolet (UV) and visible lights, CO oxidation, and supercapacitors. Their physicochemical properties were examined by field-emission scanning electron microscopy, X-ray diffraction analysis, Fourier-transform infrared spectroscopy, and UV-visible absorption spectroscopy. It was shown that their performances were highly dependent on the morphology, thermal treatment procedure, and TiO₂ overlayer coating.

Preparation of TiO₂-Decorated Boron Particles by Wet Ball Milling and their Photoelectrochemical Hydrogen and Oxygen Evolution Reactions

TiO₂-coated boron particles were prepared by a wet ball milling method, with the particle size distribution and average particle size being easily controlled by varying the milling operation time. Based on the results from X-ray photoelectron spectroscopy, transmission electron microscopy, energy dispersive X-ray analysis, and Fourier transform infrared spectroscopy, it was confirmed that the initial oxide layer on the boron particles surface was removed by the wet milling process, and that a new B-O-Ti bond was formed on the boron surface. The uniform TiO₂ layer on the 150 nm boron particles was estimated to be 10 nm thick. Based on linear sweep voltammetry, cyclic voltammetry, current-time amperometry, and electrochemical impedance analyses, the potential for the application of TiO₂-coated boron particles as a photoelectrochemical catalyst was demonstrated. A current of 250 μA was obtained at a potential of 0.5 V for hydrogen evolution, with an onset potential near to 0.0 V. Finally, a current of 220 μA was obtained at a potential of 1.0 V for oxygen evolution.