Hierarchical Architectured Dahlia Flower-Like NiCo₂O₄/NiCoSe₂ as a Bifunctional Electrode for High-Energy Supercapacitor and Methanol Fuel Cell Application

Abstract

We report unique hierarchical dahlia flower-like NiCo 2 O 4 nanograss/NiCoSe 2 nanosheets on Ni foam (NCO/NCS/NF) as bifunctional binder-free electrodes for high energy density hybrid supercapacitors and methanol electro-oxidation applications. NCO/ NCS/NF is synthesized by a facile hydrothermal method followed by an electrodeposition process. As a supercapacitor electrode, NCO/NCS/NF exhibits a superior specific capacitance of 2045.5 F g −1 (227 mAh g −1 or 818 C g −1 ) at 1.8 A g −1 . The assembly of a hybrid NCO/ NCS/NF//AC device delivers impressive specific energy of 54.5 Wh kg −1 at 350 W kg −1 with durable cyclic stability of 82.5% after 10,000 charge−discharge cycles. NCO/NCS/NF as an electrocatalyst toward methanol oxidation yields a high current density of 130 mA cm −2 at 0.5 V and a low onset potential of 0.13 V, in comparison to other reported catalysts. Such high electrochemical performance of a binder-free NCO/NCS/NF electrode is attributed to the synergistic effect between the bimetallic oxides and selenides, core−shell nanostructure, hierarchically aligned architectures of nanograss/nanosheets, and conductive coatings of NCS to provide rapid charge transfer reactions. To the best of author's knowledge, this is the first report of a 3D hierarchical NCO/NCS/NF 1D/2D nanostructure toward a bifunctional binder-free electrode for energy storage and conversion technologies.

Highly Stable NiCoZn Ternary Mixed-Metal-Oxide Nanorods as a Low-Cost, Non-Noble Electrocatalyst for Methanol Electro-Oxidation in Alkaline Medium

“…Unlike other electrocatalysts, due to high surface area, NCZMMO/GCE maintains linear growth even at higher scan rates. The redox peaks observed at 0.3 and 0.43 V are due to the transitions between Ni 2+ /Ni 3+ and Co 3+ /Co 4+ states Figure c displays the CV curve of NCZMMO/GCE in 1.0 M KOH with a range of MeOH concentrations of 0.1–0.5 M. The CV current increases with increasing MeOH concentration, indicating the dependence of MeOH peak current on MeOH concentration with an onset potential of ∼0.30 V (vs Ag|AgCl).…”

“…The redox peaks observed at 0.3 and 0.43 V are due to the transitions between Ni 2+ /Ni 3+ and Co 3+ /Co 4+ states. 25 Figure 4c displays the CV curve of NCZMMO/GCE in 1.0 M KOH with a range of MeOH concentrations of 0.1−0.5 M.…”

Dicyanamide Anion-Based Ionic Liquid-Functionalized Graphene-Supported Pt Catalysts for Boosting Methanol Electrooxidation

“…It is different from the graph in the absence of methanol, and two typical oxidation peaks are obviously observed in all samples. To some extent, this is similar to the reaction of some catalysts in the presence and absence of methanol in alkaline electrolyte solution . Pt is the active substance to promote MOR in the anodic catalyst.…”

“…To some extent, this is similar to the reaction of some catalysts in the presence and absence of methanol in alkaline electrolyte solution. 43 Pt is the active substance to promote MOR in the anodic catalyst. The reaction process of the methanol molecule on the Pt surface is as follows: 44…”

ZIF-8@ZIF-67-Derived Co Embedded into Nitrogen-Doped Carbon Nanotube Hollow Porous Carbon Supported Pt as an Efficient Electrocatalyst for Methanol Oxidation

“…Direct methanol fuel cells (DMFCs) play an important role in energy conversion and storage [2,3]. Developing highly-active and low-cost anode catalysts for DMFCs is the main prerequisite for the commercialization of energy conversion systems [4,5]. Even though Pt is the most widely applied anode catalysts for DMFCs at present [6,7], its drawbacks of low electrocatalytic stability, high cost, and the easily poisoned by oxidation intermediates such as CO, have impeded its practical applications [8].…”