Co3O4-Impregnated NiO-YSZ: An Efficient Catalyst for Direct Methane Electrooxidation

Co₃O₄-impregnated NiO-YSZ (yttria-stabilized zirconia) is a possible electrocatalyst for direct methane electrooxidation with both high catalytic activity and the ability to mitigate coking. The physical and electrochemical properties of Co₃O₄-impregnated NiO-YSZ anodes are investigated and benchmarked against NiO-YSZ and CeO₂-impregnated NiO-YSZ anodes. The following methane electrooxidation activity trend: Co₃O₄-impregnated NiO-YSZ > CeO₂-impregnated NiO-YSZ > NiO-YSZ with i_o (exchange current density) values of 88, 83, and 2 mA cm^-2, respectively, is obtained in the high overpotential region. The high activity of Co₃O₄-impregnated NiO-YSZ is attributed to the changes in the electronic structure and microstructure with the incorporation of nickel into the lattice of Co₃O₄ as observed using X-ray photoelectron spectroscopy, temperature-programmed reduction, high-resolution transmission electron microscopy, and field emission scanning electron microscopy. Co₃O₄-impregnated NiO-YSZ also demonstrated the least coking during operation, confirming its utility as a methane electrooxidation catalyst.

In situ synthesis of a 3D highly porous NiO film electrode with enhanced performance for supercapacitors

The in situ synthesis of a 3D highly porous NiO film on nickel foam has been successfully achieved through a simple hydrothermal-heat treatment strategy and the fabricated NiO electrode exhibited excellent performance for supercapacitor applications.

Tailoring NiO Nanostructured Arrays by Sulfate Anions for Sodium-Ion Batteries

In this contribution, a novel sulfate-ion-controlled synthesis is developed to fabricate freestanding nickel hydroxide nanoarrays on Ni substrate. As an inorganic morphology-controlled agent, SO₄^2- ions play a critical role in controlling the crystal growth and the nanoarray morphologies, by modulating the growth rate of adsorbed crystal facets or inserting into the metal hydroxide interlayers. By controlling the SO₄^2- concentration, the nanostructured arrays are tailored from one-dimensional (1D) Ni(SO₄ )_0.3 (OH)_1.4 nanobelt arrays to hierarchical β-Ni(OH)₂ nanosheet arrays. With further graphene oxide modification and postheat treatment, the obtained NiO/graphene hybrid nanoarrays show great potential for high-performance sodium-ion batteries, which exhibit a cyclability of 380 mAh g^-1 after undergoing 100 cycles at 0.5 C and reach a rate capability of 335 mA h g^-1 at 10 C.

Mesoporous NiO nanosphere: a sensitive strain sensor for determination of hydrogen peroxide

Exploring the sensitive and reliable methods for the determination of hydrogen peroxide (H₂O₂) is a crucial issue for the health and environmental challenges. Herein, we demonstrate a facile, but rational and effective solvothermal approach to the synthesis of hierarchical NiO mesoporous nanospheres (NiO-MNS) as an effective non-enzymatic sensor towards the H₂O₂ detection. Owing to the intercalation and stabilization effect of polyethylene glycol for the Ni(OH)₂ intermediate, the NiO mesoporous nanosphere (NiO-MNS) product is consistent with the low-dimensional nanostructured NiO blocks with large surface area and plentiful mesopores after the calcination treatment. The obtained NiO-MNS sensor presents superior electrochemical performance with a high sensitivity (236.7 μA mM⁻¹ cm⁻²) and low limit of detection (0.62 μM), as well as the good selectivity and reliability for the further application of H₂O₂ detection. In addition, the unraveling mechanism of the mesopores formation derived from the in situ measurements also offers the valuable guidance for the future design of porous materials for electrochemical devices and other applications.

The NiO mesoporous nanosphere constructing from the low-dimensional nanostructured NiO blocks presents the excellent electrochemical activity for H₂O₂ detection.

Two-step controllable preparation of NiO nanocrystal anchored reduced graphene oxide sheets and their electrochemical performance as supercapacitors

A feasible and expandable way to prepare homogenous NiO nanocrystal coated reduced graphene oxide (rGO-NiO) for high performance supercapacitor electrodes.

Single-Step Electrophoretic Deposition of Non-noble Metal Catalyst Layer with Low Onset Voltage for Ethanol Electro-oxidation

A single-step electrophoretic deposition (EPD) process is used to fabricate catalyst layers which consist of nickel oxide nanoparticles attached on the surface of nanographitic flakes. Magnesium ions present in the colloid charge positively the flake's surface as they attach on it and are also used to bind nanographitic flakes together. The fabricated catalyst layers showed a very low onset voltage (-0.2 V vs Ag/AgCl) in the electro-oxidation of ethanol. To clarify the occurring catalytic mechanism, we performed annealing treatment to produce samples having a different electrochemical behavior with a large onset voltage. Temperature dependence measurements of the layer conductivity pointed toward a charge transport mechanism based on hopping for the nonannealed layers, while the drift transport is observed in the annealed layers. The hopping charge transport is responsible for the appearance of the low onset voltage in ethanol electro-oxidation.

Strain Engineering to Modify the Electrochemistry of Energy Storage Electrodes

Strain engineering has been a critical aspect of device design in semiconductor manufacturing for the past decade, but remains relatively unexplored for other applications, such as energy storage. Using mechanical strain as an input parameter to modulate electrochemical potentials of metal oxides opens new opportunities intersecting fields of electrochemistry and mechanics. Here we demonstrate that less than 0.1% strain on a Ni-Ti-O based metal-oxide formed on superelastic shape memory NiTi alloys leads to anodic and cathodic peak potential shifts by up to ~30 mV in an electrochemical cell. Moreover, using the superelastic properties of NiTi to enable strain recovery also recovers the electrochemical potential of the metal oxide, providing mechanistic evidence of strain-modified electrochemistry. These results indicate that mechanical energy can be coupled with electrochemical systems to efficiently design and optimize a new class of strain-modulated energy storage materials.

Influence of particle size on performance of a nickel oxide nanoparticle-based supercapacitor

Particle size effects of Nickel oxide (NiO) as an active material on its supercapacitor performance were investigated.

Synthesis of shape-controlled NiO–graphene nanocomposites with enhanced supercapacitive properties

The flowerlike and polyhedral NiO–graphene composites show high supercapacitive performances which were synthesized using a facile hydrothermal method.