From Co-MOF to CoNi-MOF to Ni-MOF: A Facile Synthesis of 1D Micro-/Nanomaterials

Abstract

Controlling the growth of metal–organic frameworks (MOFs) at the micro-/nanoscopic scale will result in new physical properties and novel functions into the materials without changing the chemical identities and the characteristic features of the MOFs themselves. Herein, we report a facile approach to synthesize a series of MOFs [Co-MOF, Co x Ni y -MOFs (x and y represent the molar ratio of Co2+ and Ni2+ and x/y = 1:1, 1:5, 1:10, 1:15, and 1:20), and Ni-MOF] with a one-dimensional micro-/nanoscaled rod-like architecture. From Co-MOF to Co x Ni y -MOFs to Ni-MOF, the diameters of the rods turn to be spindly with the increase of Ni2+ content which will facilitate the supercapacitor performances. Interestingly, Co1Ni20-MOF exhibits a highest specific capacity of 597 F g–1 at 0.5 A g–1 and excellent cycle performance (retained 93.59% after 4000 cycles) among these MOF materials owing to its micro-/nanorod structure with a smaller diameter and the synergy effect between the optimum molar ratio of Co2+ and Ni2+.

In Situ Synthesis of MOF‐74 Family for High Areal Energy Density of Aqueous Nickel–Zinc Batteries

“…Metal-organic frameworks (MOFs) are a class of porous crystalline materials constructed from metal ions/clusters and organic linkers, which featured the tunable pore size and accessible metal sites. [1,2] MOFs are promising candidates for gas adsorption, [3,4] separation, [5,6] catalysis, [7][8][9] etc. Fortunately, NZBs is plagued by the weak conductivity of cathode materials, which will significantly affect the transfer rate of electrons with a high mass-loading, thus reducing electrochemical properties such as specific capacity and rate performance.…”

Controlled synthesis of a cobalt-organic framework: hierarchical micro/nanospheres for high-performance supercapacitors

“…The specific capacitance is 255 F g −1 , 430 F g −1 , and 267 F g −1 at 0.5 A g −1 for Co-MOF/M1, Co-MOF/M2 and Co-MOF/M3, respectively, which is much larger than 90 F g −1 for Co-MOF at the same current density. 27 Specifically, this value for the Co-MOF/M2 electrode is much higher than those of previously reported cobalt-based materials, such as Co-NC3, 38 COP, 39 and Co-BTB-I-450. 40 The GCD curves at various current densities from 0.5 to 5.0 A g −1 in the potential window of 0.49 V were obtained.…”

“…A Co-MOF 27 named [{Co(3,5-pdc)(H 2 O) 4 ·6H 2 O}] n (H 2 pdc = pyridine-3,5-dicarboxylic acid) was selected as the target because it possesses rich coordinated water molecules that would be lost in the temperature range of 100–175 °C, leading to the exposure of active metal sites. The hierarchical Co-MOF micro/nanospheres were prepared according to a modified literature method.…”

“…S1 †). Different from the Co-MOF, 27 the obtained Co-MOF/M1-3 features a hierarchical micro/nanospherical morphology with rich channels (Fig. S1 †), which facilitates the exposure of active sites and fast electron and electrolyte transport.…”

“…Compared with the Co-MOF, 27 the excellent supercapacitor performance of the Co-MOF-based hierarchical micro/nanospheres, especially Co-MOF/M2, could be attributed to the following aspects: the hierarchical Co-MOF-based micro/nanospheres, which lose the coordination water molecules, enabled the exposure of electroactive sites to promote the reactions, resulting in a high specific capacity. In addition, the rich channels of hierarchical Co-MOF-based micro/nanospheres could enlarge the interfacial contact between the electrode and elec-trolyte and shorten mass diffusion pathways to boost the kinetics of redox reactions at the electrode surface for an enhanced rate capability.…”