Facile and green synthesis of mesoporous Co3O4 nanocubes and their applications for supercapacitors

Abstract

Nanostructured Co3O4 materials attracted significant attention due to their exceptional electrochemical (pseudo-capacitive) properties. However, rigorous preparation conditions are needed to control the size (especially nanosize), morphology and size distribution of the products obtained by conventional methods. Herein, we describe a novel one step shape-controlled synthesis of uniform Co3O4 nanocubes with a size of 50 nm with the existence of mesoporous carbon nanorods (meso-CNRs). In this synthesis process, meso-CNRs not only act as a heat receiver to directly obtain Co3O4 eliminating the high-temperature post-calcination, but also control the morphology of the resulting Co3O4 to form nanocubes with uniform distribution. More strikingly, mesoporous Co3O4 nanocubes are obtained by further thermal treatment. The structure and morphology of the samples were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. A possible formation mechanism of mesoporous Co3O4 nanocubes is proposed here. Electrochemical tests have revealed that the prepared mesoporous Co3O4 nanocubes demonstrate a remarkable performance in supercapacitor applications due to the porous structure, which endows fast ion and electron transfer.

Fabrication of porous nanosheet-based Co 3 O 4 hollow nanocubes for electrochemical capacitors with high rate capability

“…For comparision, the electrochemical performances of Co 3 O 4 based electrode materials in other literatures (solid/hollow nanocubes, nanonets, nanoboxes/ nanocages, hollow spheres, and nanosheets) are listed in Table 1 [8,18,19,24,[42][43][44]. For example, Wang et al reported a 3D-nanonet hollow structured Co 3 O 4 for high rate capacity supercapacitors, which shows a C CD of 739 F g -1 at 1 A g -1 and 533 F g -1 at 15 A g -1 .…”

“…So far, various Co 3 O 4 nanostructures (nanoparticles, nanowires, nanobelts, nanoflakes, nanocubes, and hollow spheres) have been successfully synthesized for high performance electrode materials [13][14][15][16][17][18][19]. And it is demonstrated that porous hierarchical structures can bring about excellent performances in electrochemical energy storage systems with their high specific surface area.…”

Ethanol-assisted solvothermal synthesis of porous nanostructured cobalt oxides (CoO/Co3O4) for high-performance supercapacitors

“…Electrochemical capacitors (supercapacitors), with irreplaceable properties of long service lifetime, fast charge-discharge process, green environmental protection and high energy efficiency, have been widely employed in the power back-up systems, public transportation and medical devices, etc., [1,2]. Supercapacitors (SCs) are generally of two varieties based on the charge storage mechanism: electric double-layer capacitors (EDLCs) and faradaic pseudocapacitors.…”

Co3O4 Nanorods with Self-assembled Nanoparticles in Queue for Supercapacitor

“…Co 3 O 4 nanowires prepared by hydrothermal method only have a capacitance of 81 F g -1 at 0.3 A g -1 [52]. Co 3 O 4 nanocubes obtained by hydrothermal method achieve a capacitance of 120 F g -1 at 0.2 A g -1 [40]. While, Co 3 O 4 -T represents a capacitance value of 137 F g -1 even with at a high current density of 1.5A g -1 , proofing the good electrochemical properties of Co 3 O 4 -T.…”

“…. The larger surface of Co 3 O 4 -T may be due to structure of its three network consisting of the nanorods [16,30,40]. Besides, the existence of mesopores caused by organic molecule decomposing has a contribution to the larger surface area [16].…”