Synthesis of MnO2 Nanoparticles Confined in Ordered Mesoporous Carbon Using a Sonochemical Method

Abstract

A sonochemical method has been successfully used in order to incorporate MnO2 nanoparticles inside the pore channels of CMK‐3 ordered mesoporous carbon. Modification of the intrachannel surfaces of CMK‐3 to make them hydrophilic enables KMnO4 to readily penetrate the pore channels. At the same time, the modification changes the surface reactivity, enabling the formation of MnO2 nanoparticles inside the pores of CMK‐3 by the sonochemical reduction of metal ions. The resultant structures were characterized by X‐ray diffraction (XRD), nitrogen adsorption, and transmission electron microscopy (TEM). CMK‐3 with 20 wt.‐% loading of MnO2 inside CMK‐3 delivered an improved discharge performance of 223 mA h g–1 at a relatively high rate of 1 A g–1. Almost no decrease in specific capacity is observed for the second cycle, and a discharge capacity of more than 165 mA h g–1 is retained after 100 cycles. This is attributed to the nanometer‐sized MnO2 formed inside CMK‐3 and the high surface area of the mesopores (3.1 nm) in which the MnO2 nanoparticles are formed.

Fe3O4 Nanoparticles Confined in Mesocellular Carbon Foam for High Performance Anode Materials for Lithium‐Ion Batteries

“…Ordered mesoporous carbon, CMK-3, has been previously employed to prepare electrochemically active carbon composites. [ 11 ] However, after loading electrochemically active nanomaterials, it may be diffi cult for the electrolyte to access the active materials inside the pores due to the single dimensions and small pore sizes ( ∼ 3-4 nm) of the CMK-3. In order to accommodate a large quantity of electrochemically active materials and also enable facile penetration of the electrolyte into the pores, it is nece ssary to develop mesoporous carbons with larger pore sizes and volumes.…”

Hierarchical manganese oxide/carbon nanocomposites for supercapacitor electrodes

“…MnO 2 is currently considered as one of the most promising redox components for supercapacitor applications owning to its high capacitance, low cost, and low toxicity. To date, various MnO 2 /carbon composites have been synthesized, such as composites with planar graphite [25], acetylene black [26,27], ordered mesoporous carbon [28,29], carbon nanotubes [30][31][32][33], and carbon aerogels and nanofoams [34]. These have generally been synthesized by physical mixing of MnO 2 with carbon [31], or electrochemically or chemically depositing MnO 2 on carbon substrates [32,33].…”

“…These have generally been synthesized by physical mixing of MnO 2 with carbon [31], or electrochemically or chemically depositing MnO 2 on carbon substrates [32,33]. Among these synthesis methods, the chemical deposition of MnO 2 through self-limiting redox reactions of KMnO 4 and carbon is of particular interest [25][26][27][28][29]. In such a synthesis, carbon substrates are exposed to KMnO 4 solution at room temperature or an elevated temperature, and a spontaneous redox reaction described as…”

Nanostructure-controlled Materials for Electrochemical Charging–Discharging

“…MnO 2 nanoparticles incorporated inside the pore channels of CMK-3 mesoporous carbon showed higher discharge performance than a MnO 2 -coated acetylene black composite. 48 However, the capacity decreased with increasing MnO 2 -loading amount probably due to the decrease in mesoporous space with the incorporation of the particles. Similar behavior was also observed on LiMnPO 4 -embedded nanoporous carbons.…”