Tuning the electrocatalytic performances of Ni-MOF with combined tungsten compounds (WO3-x/WS2-x) decorated rGO by interface coupling for efficient water oxidation

Abstract

The novel design of noble metal-free electrocatalyst with new structure/combination and cost-effectiveness are vital sources for the featuring hydrogen energy sector (mainly hydrogen and oxygen evolution reaction (OER)) in the viewpoint of commercialization of water electrolyzers. Herein, we constructed a new kind of ternary rG-W-N electrocatalyst (reduced graphene oxide - a new formation of heterostructured tungsten compound W-O-S (WO3-x/WS2-x) - Ni-MOF) for enhancing the OER activity. Interestingly, the seeded W-O-S grew from inside of rGO layer with a spherical formation in binary composition. The excellent electrocatalyst for OER was identified by systematically investigating from the binary and ternary electrocatalysts using different concentrations. The homogeneous rG-W-N nanocomposite exhibits remarkable performance for water oxidation, with an ultra-low over potential value of 170 mV at 10 mA cm−2 towards OER performance. In addition, it shows an efficient stability performance after 5000 cycles. The rG-W-N electrocatalyst boosts the sluggish intermediate pathway for OER, which is the primary reason for attaining the lowest over potential. The electronic and synergetic effects in rG-W-N leads to interfacial interaction/connectivity between the ternary materials and large active sites enhance the efficient charge transfer reaction.