Engineering MoS2 nanostructures from various MoO3 precursors towards hydrogen evolution reaction
MoS2-based nanomaterials could be considered to be the promising effective electrocatalysts to replace precious metal catalysts toward hydrogen evolution reaction. However, the understanding on the effect of MoO2 in MoS2-based catalysts for hydrogen evolution reaction is ambiguous. In this paper, MoS2 nanoflowers with 210-430 nm in diameter were hydrothermally synthetheized by the reduction of α-MoO3 particles with KSCN in hydrochloric acidic medium. Similarly, MoO2-MoS2-B nanoflowers and MoO2-MoS2-R nanoflowers were fabricated using α-MoO3 nanobelts and h-MoO3 microrods as Mo sources, respectively. Systematic studies on synthetic parameters verified that it favored the formation of MoS2 nanoflowers with the high acitidy, low MoO3/KSCN ratio and high temperature. The resultant nanoflowers serverd as electrocatalysts to drive hydrogen evolution in acidic solution. The MoS2 nanoflowers showed a relatively higher activity with the potential of 256 mV at 10 mA/cm2 than that of MoO2-MoS2-B nanoflowers (283 mV) and MoO2-MoS2-R nanoflowers (305 mV). Furthermore, MoS2 nanoflowers catalyts maintained the high stability after 1000 cycles and long-term durability for 5 h. The high catalytic activity could be ascribed to the large exposure of the Mo-S species and small amounts of Mo-O species on MoS2-based catalysts surface.