Synthesis of scalable 1T/2H–MoSe2 nanosheets with a new source of Se in basic media and study of their HER activity

In this report MoSe2 nanosheets were fabricated using new precursors of MoCl5 and Na2SeO3 and a very simple chemical procedure without using inert atmosphere and complex methods for preparing Se ion source. The structural properties of fabricated nanosheets were examined by means of XRD, field emission scanning electron microscopy (FESEM), elemental mapping of energy dispersive x-ray spectroscopy (EDS), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy and isotherm gas adsorption-desorption technique. The results showed the nanosheets are mixed phase metallic-semiconductor 1T-2H with thicknesses about 3.6–6.1 nm and are stable for several months. The effective surface area is obtained 28 m2 g−1 and mean pore size of 6–8 nm for MoSe2 nanosheets. Electro-impedance spectroscopy showed low resistivity of nanosheets due to presence of metallic phase of MoSe2. HER activity of nanosheets obtains a Tafel slope of 60 mV.dec−1 and high current density values up to 150 mA cm−2 and the value of over potential at 10 mA cm−2 is 155 mV.