Electrochemical capacity retention of nearly X-ray amorphous nanostructured manganese oxide (nanoMnO 2 ) synthesized by mixing directly KMnO 4 with ethylene glycol under ambient conditions for supercapacitor studies is enhanced significantly. Although X-ray diffraction (XRD) pattern of nanoMnO 2 shows poor crystallinity, it is found that by Mn K-edge X-ray absorption near edge structure (XANES) measurement that the nanoMnO 2 obtained is locally arranged in a δ-MnO 2 -type layered structure composed of edge-shared network of MnO 6 octahedra. Field emission scanning electron microscopy and XANES measurements show that nanoMnO 2 contains nearly spherical shaped morphology with δ-MnO 2 structure, and 1D nanorods of R-MnO 2 type structure (powder XRD) in the annealed (600 °C) sample. Volumetric nitrogen adsorption-desorption isotherms, inductively coupled plasma analysis, and thermal analysis are carried out to obtain physicochemical properties such as surface area (230 m 2 g -1 ), porosity of nanoMnO 2 (secondary mesopores of diameter 14.5 nm), water content, composition, etc., which lead to the promising electrochemical properties as an electrode for supercapacitor. The nanoMnO 2 shows a very high stability even after 1200 cycles with capacity retention of about 250 F g -1 .

Mesoporous carbon nitrides (MCN) with C3N4 stoichiometry could find applications in fields ranging from catalysis, sensing, and adsorption–separation to biotechnology. The extension of the synthesis of MCN with different nitrogen contents and chemical structures promises access to a wider range of applications. Herein we prepare mesoporous C3N5 with a combined triazole and triazine framework via a simple self‐assembly of 5‐amino‐1H‐tetrazole (5‐ATTZ). We are able to hybridize these nanostructures with graphene by using graphene–mesoporous‐silica hybrids as a template to tune the electronic properties. DFT calculations and spectroscopic analyses clearly demonstrate that the C3N5 consists of 1 triazole and 2 triazine moieties. The triazole‐based mesoporous C3N5 and its graphene hybrids are found to be highly active for oxygen reduction reaction (ORR) with a higher diffusion‐limiting current density and a decreased overpotential than those of bulk g‐C3N4.

Through a flame-melting/rapid-cooling process, metastable forms of solid state compounds can be discovered. We describe here an example where both slow and rapid crystallizations of a stoichiometric "KInSnSe(4)" melt give rise to kinetic forms of KInSnSe(4). These forms (alpha- and beta-) convert to the thermodynamically stable gamma-form upon heating below the melting point.