Modulated electrochemical oxygen evolution catalyzed by MoS2 nanoflakes from atomic layer deposition.

Electrochemical water splitting into H2 and O2 has attracted wide attention owing to the urgent need for clean and renewable energy sources. However, the scarcity and high-cost limit the large-scale application of noble metal catalysts such as IrO2 and RuO2. In this work, as a low-cost catalyst for the electrochemical O2 evolution reaction (OER), MoS2 nanoflakes were obtained by atomic layer deposition (ALD) using MoCl5 and H2S on carbon fiber paper surface. According to the results of electrochemical measurements, the MoS2 nanoflakes exhibit an excellent catalytic activity, and the activity can be modulated by controlling the density and the internal resistance of MoS2 nanoflakes. Moreover, the plasma treatment can further improve the activity of MoS2 nanoflakes, and the reason was discussed through the measurements of contact angle, electrochemical impedance spectroscopy, and electrochemically active surface area. The MoS2 nanoflakes obtained by ALD possess huge values for electrochemical OER as a catalyst.