Amorphous Mo-doped NiS0.5 Se0.5 Nanosheets@Crystalline NiS0.5 Se0.5 Nanorods for High Current-density Electrocatalytic Water Splitting in Neutral Media.

ABSTRACT

It is vitally important to develop highly active, robust and low-cost transition metal-based electrocatalysts for overall water splitting in neutral solution especially at large current density. In this work, amorphous Mo-doped NiS0.5 Se0.5 nanosheets@crystalline NiS0.5 Se0.5 nanorods (Am-Mo-NiS0.5 Se0.5 ) was synthesized using a facil one-step strategy. In phosphate buffer saline solution, the Am-Mo-NiS0.5 Se0.5 shows tiny overpotentials of 48 and 209 mV for hydrogen evolution reaction (HER), 238 and 514 mV for oxygen evolution reaction (OER) at 10 and 1000 mA cm-2 , respectively. Moreover, Am-Mo-NiS0.5 Se0.5 delivers excellent stability for at least 300 h without obvious degradation. Theoretical calculations revealed that the Ni sites in the defect-rich amorphous structure of Am-Mo-NiS0.5 Se0.5 owns higher electron state density and strengthened the binding energy of H2 O, which will optimize H adsorption/desorption energy barriers and reduce the adsorption energy of OER determining step.