Amorphous Molybdenum Sulfide/Carbon Nanotubes Hybrid Nanospheres Prepared by Ultrasonic Spray Pyrolysis for Electrocatalytic Hydrogen Evolution

Developing cost‐effective electrocatalysts with high activity and stability for hydrogen evolution reaction (HER) plays an important role in modern hydrogen economy. Amorphous molybdenum sulfide (MoS x ) has recently emerged as one of the most promising alternatives to Pt‐based catalysts in HER, especially in acidic electrolytes. Here this study reports a simple ultrasonic spray pyrolysis method to synthesize hybrid HER catalysts composed of MoS x firmly attached on entangled carbon nanotube nanospheres (MoS x /CNTs). This synthetic process is fast, continuous, highly durable, and amenable to high‐volume production with high yields and exceptional quality. The MoS x /CNTs hybrid catalyst prepared at 300 °C exhibits a low overpotential of 168 mV at the current density of 10 mA cm −2 with a small Tafel slope of 36 mV dec −1 . Electrochemical measurements and X‐ray photoelectron spectroscopy analyses reveal that the CNT network not only promotes the charge transfer in corresponding HER process but also enhances the stability of the active sites in MoS x . This work demonstrates that ultrasonic spray pyrolysis is a reliable and versatile approach for synthesizing amorphous MoS x ‐based HER catalysts.