Ion-exchange strategy for fabricating highly dispersed Co–MoS2 on N-doped graphene for efficient bifunctional electrocatalytic water splitting.

Recently, the pivotal to electrocatalytic water splitting is developing efficient and earth-abundant electrocatalysts to accelerate the sluggish kinetics of hydrogen and oxygen evolution reactions (HER and OER). In this work, (NH 4) 2 MoS 4 derived from polyoxometalates ((NH 4) 6 Mo 7 O 24 ·4H 2 O) were immobilized onto the ion exchange resin D314, and highly dispersed Co-molybdenum disulfide (Co–MoS 2 @NG-4) on nitrogen-doped graphene catalyst was prepared. The optimized Co–MoS 2 @NG-4 shows excellent electrocatalytic performance for HER and OER. Specifically, the low overpotentials of 202 and 352 mV are required to drive the current density of 10 mA cm−2 with the small Tafel slope of 77.30 and 153.50 mV dec−1 for HER and OER, respectively. The Co–MoS 2 @NG-4 demonstrates excellent stability, maintaining a robust operation for 5000 cyclic tests with no detectable stability decay. Porous structure endows Co–MoS 2 @NG-4 with more active centers, increasing its specific surface area and ultimately improving its catalytic performance. [Display omitted] • Synthesized Co–MoS 2 @NG-4 catalyst using ion-exchange and thermal reduction methods. • The porous structure and heteroatom doping improve the electrocatalytic activity. • The Co–MoS 2 @NG-4 exhibits excellent electrochemical activity for both HER and OER. • The Co–MoS 2 @NG-4 exhibits exceptional stability. [ABSTRACT FROM AUTHOR]