Synthesis of binder-free MoSe2 nanoflakes as a new electrode for electrocatalytic hydrogen evolution

Molybdenum diselenide nanoflakes, as an electrocatalyst for hydrogen evolution reactions, were easily synthesized by a hydrothermal method, and hydrogen reduction electrodes were prepared for the first time via annealing in the vacuum, removing the need for Nafion polymer for coating molybdenum diselenide on conductive glass substrates to increase catalytic activities. Crystalline structures and morphologies of the samples were studied by X-ray diffractometry, field emission scanning electron microscopy, and transmission electron microscopy. FESEM and TEM images showed the layered structure of the synthesized nanoparticles and also the highly porous structure of the coated electrodes. The thickness of the synthesized nanoflakes was 14 nm. Energy-dispersive X-ray spectroscopy showed that the average atomic ratio of selenium/molybdenum is very close to 2. UV-Vis spectrophotometry showed the two characteristic peaks of molybdenum diselenide nanoflakes at 705 and 800 nm. The novel method for preparing electrodes could increase the catalytically active lateral surface area and also increase the electron mobility, ultimately enhancing the catalytic activity of electrodes. Hydrogen reduction reaction tests showed the onset potential about 107 mV and the Tafel slope about 74 mV/decade, and also they showed a high stability for hydrogen production.