Synthesis of very small molybdenum disulfide nanoflowers for hydrogen evolution reaction

Among various transition metal dichalcogenides, molybdenum disulfides such as molybdenum disulfide nanoflowers (MoS2 NFs) can effectively catalyze a hydrogen evolution reaction (HER) because of the abundance, ease of processing, and high catalytic activity of MoS2. The main disadvantage of using MoS2 NFs for HER on the industrial scale is their low density and number of active sites. Herein, we propose for the first time a facile, inexpensive, and scalable route for fabricating extremely small MoS2 NFs (SNFs). The size of the synthesized MoS2 SNFs (50–90 nm) is much lower than that of conventional MoS2 NFs (900–1500 nm), which significantly increases the number of catalytically active sites. In addition, the in situ doping of N atoms considerably enhances the catalytic activity of the prepared MoS2 SNFs. MoS2 SNFs exhibit superior electrocatalytic activity toward HER with a low Tafel slope 49 mV·dec−1, an overpotential of 270 mV at a current density of 50 mA·cm−2, a large surface area of 98 m2·g−1, and very high stability in an acidic environment. The obtained results indicate that MoS2 SNFs can be potentially used for energy storage and electrochemical applications.