Three-Dimensional Cobalt Oxide Microstructures with Brush-like Morphology via Surfactant-Dependent Assembly

Abstract

In this study, three-dimensional cobalt oxide microstructures were developed. Cobalt oxide microdumbbells and microspheres, assembled by nanowires and primary particles, were successfully synthesized by a multistep hydrothermal method. Of all of the structures, the cobalt oxide microdumbbell electrode possesses the largest surface area of 70.8 m(2) g(-1) and the highest specific capacitance of 407.5 F g(-1). The as-prepared electrode also demonstrates excellent electrochemical stability and retains 97.5% of the initial capacitance after 2000 charge-discharge cycles. This performance is attributed to the desirable morphology, uniform microarchitecture stability, and high surface area. The results show that the as-fabricated Co3O4 is a promising electrode material for supercapacitor applications.

A Microribbon Hybrid Structure of CoOx‐MoC Encapsulated in N‐Doped Carbon Nanowire Derived from MOF as Efficient Oxygen Evolution Electrocatalysts

“…To study how the charge transport inside the four electrocatalysts influences their catalytic activity toward hydrogen evolution, we conducted the electrochemical impedance spectroscopy investigations of CoOx‐MoC/NC 1–3 which derived from MOFs and IrO 2 /C. As shown in Figure S4 (Supporting Information), the semicircles in the high‐frequency area of the Nyquist plot were ascribed to the charge‐transfer resistance ( R ct ), and a lower value of R ct denotes a faster reaction rate . All of the CoOx‐MoC/NCs have similar charge‐transfer resistances (Table S4, Supporting Information).…”

“…As shown in Figure S4 (Supporting Information), the semicircles in the high-frequency area of the Nyquist plot were ascribed to the charge-transfer resistance (R ct ), and a lower value of R ct denotes a faster reaction rate. [37] All of the CoOx-MoC/NCs have similar charge-transfer resistances ( The aforementioned superior electrochemical behaviors of the microstructure may be ascribed to three reasons. First, Co/ Mo compositional tuning, MoC has been found to promote the water splitting electrochemical reaction, whereas a low ratio of Co/Mo may not be able to provide sufficient catalytic sites, which is unfavorable for OER.…”

One-step synthesis of magnetically recyclable Co@BN core–shell nanocatalysts for catalytic reduction of nitroarenes

“…The spectral position located at 1368 cm À1 belongs to the characteristics of the high frequency vibration Raman peaks (E 2g ) between boron nitride layers. [50][51][52] Besides, it is noteworthy that there are no Raman signals from Co 3 O 4 (472 cm À1 (E g ), 507 cm À1 (F 2g ) and 662 cm À1 (A 1g )) 53 and CoO (1000-1100 cm À1 ). 48 This indicates that the Co@BN samples do not contain detectable cobalt oxide, which is in good accordance with the results of XRD and FTIR analysis.…”

Hydrothermal Preparation of Homogeneous Cobalt Oxide Nanomaterials as Stable Anodes for Superior Lithium Ion Batteries

“…3b and d. Notably, a maximum slope can be observed at the 50th cycle, which may correspond to the lowest Q w [50,51]. As a consequence, the Co 3 O 4 materials synthesized are able to effectively enhance the Li-ion and charge diffusion during the repetitive Li-ion insertion/ extraction process.…”