Facile Synthesis of Core/Shell-like NiCo2O4-Decorated MWCNTs and its Excellent Electrocatalytic Activity for Methanol Oxidation

Abstract

The design and development of an economic and highly active non-precious electrocatalyst for methanol electrooxidation is challenging due to expensiveness of the precursors as well as processes and non-ecofriendliness. In this study, a facile preparation of core-shell-like NiCo2O4 decorated MWCNTs based on a dry synthesis technique was proposed. The synthesized NiCo2O4/MWCNTs were characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and selected area energy dispersive spectrum. The bimetal oxide nanoparticles with an average size of 6 ± 2 nm were homogeneously distributed onto the surface of the MWCNTs to form a core-shell-like nanostructure. The NiCo2O4/MWCNTs exhibited excellent electrocatalytic activity for the oxidation of methanol in an alkaline solution. The NiCo2O4/MWCNTs exhibited remarkably higher current density of 327 mA/cm2 and a lower onset potential of 0.128 V in 1.0 M KOH with as high as 5.0 M methanol. The impressive electrocatalytic activity of the NiCo2O4/MWCNTs is promising for development of direct methanol fuel cell based on non-Pt catalysts.

Nickel cobalt oxide nanowires‐modified hollow carbon tubular bundles for high‐performance sodium‐ion hybrid capacitors

“…Apparently, the HRTEM image of the composite shows the lattice spacing of 0.47 and 0.24 nm, which correspond with the interplanar spacing of NiCo 2 O 4 (111) and (311) planes, respectively . These results are similar to that of the bare NiCo 2 O 4 (Figure S1D‐F) and consistent with its d‐space in XRD consequences, indicating the polycrystalline state of the sample …”

“…31 These results are similar to that of the bare NiCo 2 O 4 (Figure S1D-F) and consistent with its d-space in XRD consequences, indicating the polycrystalline state of the sample. 21 The valence states of the NiCo 2 O 4 /CTBs composite are characterized by X-ray photoelectron spectroscopy (XPS) measurement. The full XPS spectra of the materials are presented in Figure 2A (Table S1), the ratio between Ni and Co is about 1:2, so we can further confirm that the successful preparation of NiCo 2 O 4 .…”

“…[15][16][17] Among the varied materials, NiCo 2 O 4 is regarded to be a promising candidate owning to its high specific capacity, but the wide band gap causes poor electric conductivity and inferior cycling lifespan, which further limits its applications. 18,19 Therefore, NiCo 2 O 4 nanostructures are combined with various carbonaceous materials, such as graphene, 20 MWCNTs, 21 activated carbon, 9 and carbon textiles. 22 However, most carbon materials exhibit low capacity and are expensive because of the lack of availability for sodium insertion and the complicated preparation process.…”

Novel MWCNT interconnected NiCo2O4 aerogels prepared by a supercritical CO2 drying method for ethanol electrooxidation in alkaline media

“…It has been reported that a strategy to combine both NiO and Co 3 O 4 resulted in the high electrocatalytic efficiency than their individual counterparts. For example, NiCo 2 O 4 exhibits excellent electrochemical activity due to higher electronic conductivity than either NiO or Co 3 O 4 [16,17].…”

Sea-Island-Like Morphology of CuNi Bimetallic Nanoparticles Uniformly Anchored on Single Layer Graphene Oxide as a Highly Efficient and Noble-Metal-Free Catalyst for Cyanation of Aryl Halides

“…Astonishing physicochemical properties such as elegant morphology, stability and huge specific surface make graphene nanocomposites highly suitable for the heterogeneous catalysis 16 . Particularly, mechanochemically prepared carbon nanocomposites showed enhanced catalytic performance which is mainly due to the better metal-support interaction [17][18][19][20] . For instance, inert RuO 2 -nanoparticles were tuned to highly efficient catalyst by decorating it onto single-walled carbon nanotubes (SWCNTs) by a simple 'dry synthesis' 19 .…”