Electrochemical water electrolysers are clean and renewable approach to produce hydrogen and oxygen. However, a major drawback of this system is the high overpotential required for the anodic oxygen evolution reaction (OER). Due to sluggish reaction kinetics noble metals like Ir/Ru are employed to generate substantial amount of current. The high cost of noble metals have driven research towards the development of transition metal (TM) based electrocatalysts. Among various TM electrocatalysts, Ni12P5 has shown excellent potential in OER. This work is an attempt to improve the activity of Ni12P5 with N containing conducting polymer. A M-N bond is introduced in the hybrid core-shell Co@Ni12P5/PPy microspheres, enhancing the overall charge transfer properties. PPy shell acts as a connector with the inner N binding to Ni in the Ni12P5 core. Introduction of electronegative N causes surface enrichment of Ni in Ni12P5/PPy resulting in increased number of active sites. The available outer N atom binds to Co during electrodeposition, thus introducing dual synergic M-N effects. Due to Co-N, N-Ni hybrid catalysts, the Ni2+ to Ni3+ oxidation potential is considerably decreased exposing the conductive NiOOH at low oxidation potential. These hybrid microspheres exhibit excellent OER activity with a current density of 10mA/cm2 at 1.6 V (vs RHE). The hybrid catalyst is stable for up to 500 cycles and 10000 s of chronoamperometry with a tafel slope of 48 mV/dec.

Dual synergic effect in hybrid Co@Ni12P5/PPy for enhanced OER

2019 Spring National Meeting

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