Time-dependent synthesis of molybdenum disulfide for efficient electrocatalysts

Molybdenum disulfide (MoS2) is synthesized by the easy hydrothermal method for bifunctional electrocatalysts. The synthesis time from 6 to 72 h was under controlled, and then the time dependently synthesized MoS2 samples were investigated. The morphology of MoS2 changed from flakes to flower shapes with the time. Electrochemical properties as well as catalytic activities of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are studied. The synthesized MoS2 sample at 200 °C for 48 h exhibits the best performance for HER and OER among the other samples. Low Tafel slope of 98 mV/dec with overpotential of −213 mV at the current density of −10 mA/cm2 for HER is obtained, and improved Tafel slope of 114 mV/dec with overpotential of 275 mV at the current density of +10 mA/cm2 for OER is also achieved.