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Abstract: Mg(OH)2 nanoplate with single-crystal structure was synthesized by a solvothermal method without using any surfactants or organic templates. MgO was obtained by annealing Mg(OH)2 at low temperature. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption–desorption analysis. The results indicate that MgO sample inherits the nanoplate morphology and single-crystal structure of Mg(OH)2. Moreover, MgO nanoplate has disordered mesoporous structure, large BET surface area, and high pore volume. The BET surface area and pore volume can reach up to 373.2m2/g and 0.71cm3/g. The dehydration of Mg(OH)2 during heat treatment results in the formation of mesopores. The effect of the solvothermal reaction temperature, the solvothermal reaction solvent, and the annealing temperature on the BET surface areas of MgO products was studied. [Copyright &y& Elsevier]

A new restriction effect of hard templates for the shrinkage of mesoporous polymer results in anomalous increase of the mesopore size during carbonization. [ABSTRACT FROM AUTHOR]

Abstract: Ordered mesoporous carbons (OMCs) with controllable pore sizes in the range of 4–10nm are prepared by a template procedure using 2D hexagonal MSU-H and 3D cubic KIT-6 as hard templates and boric acid as the pore expanding agent. The electrochemical performances of the as-synthesized OMCs as electrode materials for electrochemical double layer capacitors (EDLCs) are characterized by cyclic voltammetry (CV), galvanostatic charge/discharge (GC) and electrochemical impedance spectroscopy (EIS) experiments in 30wt% KOH electrolyte. The influence of the pore size distributions of OMCs on the electrochemical capacitive performances is discussed. The prepared OMCs exhibit good capacitive behaviors with the specific capacitance values ranging from 143 to 205.3Fg−1 at a voltage scan rate of 5mVs−1 and 81 to 86% retained at a high scan rate of 100mVs−1. OMC-M-2 shows the highest specific surface capacitance value of 27.5μFcm−2 at 5mVs−1 with a peak pore size of 7.8nm and a Brunauer–Emmet–Teller (BET) surface area of 729.3m2 g−1. The analysis of two kinds of pore symmetries of OMCs with the same pore size of about 6.5nm shows that the 3D cubic OMC exhibited superior capacitive performance than the 2D hexagonal OMC. [Copyright &y& Elsevier]