Microwave-assisted hydrothermal synthesis and catalytic activity study of crednerite-type CuMnO2 materials

A new and "flexible" microwave-assisted hydrothermal (MWH) synthesis of crednerite CuMnO₂ materials is proposed. Single-phase compounds are synthesized by means of the MWH method in a significantly shorter time than by conventional hydrothermal heating. CuMnO₂ single-phase compounds are obtained in the 80–180 °C temperature range, with times ranging from 5 min to 1 h, starting from nitrate reactants. The structure and the phase composition were studied by X-Ray diffraction and FT-IR spectroscopy, and reveal that all samples crystallize within the crednerite structure with the C2/m space group and without other impurities. The surface area is 59.5 m²/g for the sample obtained at 120 °C, 5 min, and 76.8 m²/g for the sample obtained at 80 °C, 5 min, respectively. The morphological analysis by transmission electron microscopy revealed plate-like nanoparticles, 20–50 nm in diameter. As application, in the case of the as-obtained products the catalytic activity was tested for hydrogen evolution in aqueous sulphide solution.