Interface synthesis of mesoporous MnO2 and its electrochemical capacitive behaviors.

Mesoporous MnO(2) has been synthesized by means of a novel, facile, and template-free method by virtue of a soft interface between CCl(4) and H(2)O without any surfactants or organometallic precursors or ligands. X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy analysis, scanning electron microscopy, and an ASAP2010 autoadsorption analyzer were applied to investigate the composition and microstructure of the as-synthesized MnO(2). The structure characterizations indicated a good mesoporous structure for as-prepared MnO(2) with an adsorption average pore diameter of 9.7 nm, mesoporous volume of 0.58 cm(3) g(-1), and Brunauer-Emmett-Teller specific surface area of 239 m(2) g(-1). Electrochemical properties of the mesoporous MnO(2) were elucidated by cyclic voltammograms, galvanostatic charge-discharge, and electrochemical impedance spectroscopy in 1 M Na(2)SO(4) electrolyte. Electrochemical data analysis demonstrated that as-synthesized MnO(2) had good capacitive behavior due to its unique mesoporous structure. A specific capacitance of ca. 220 F g(-1) could still be delivered for the mesoporous MnO(2) even at a scan rate of 100 mV s(-1).