Nickel(hydro)oxide/graphdiyne Catalysts for Efficient Oxygen Production Reaction

The transition metal-based materials have been regarded as promising electrocatalysts for oxygen evolution reaction (OER). However, achieving higher efficiency is largely limited by the valence states of metal species. Herein, different graphdiyne (GDY)-nickel composites were designed and synthesized [Ni(OH)(2)/GDY, NiOOH/GDY, and NiOx/GDY] as the electrocatalysts for OER. The NiOx/GDY possessing the mixed valence states can drive the OER more efficiently than Ni(OH)(2)/GDY and NiOOH/GDY. NiOx/GDY gives the smallest overpotential of 310 mV at 10 mA/cm(2) for OER, which is even superior to commercial RuO2 electrocatalyst. Experimental results reveal that not only the fast charge transfer induced by GDY but also the prominent roles of mixed Ni2+/Ni3+ valence states boost the OER electrocatalytic performances. The presence of the mixed valence state was demonstrated to be helpful for the charge transfer, resulting in the enhancement of the catalytic activity. This work may provide a new direction to design and fabricate high-performance materials for OER and beyond.

Automated summary

Transition metal-based materials are promising electrocatalysts for oxygen evolution reaction (OER), but efficiency is limited by metal species valence states. Graphdiyne-nickel composites, especially NiOx/GDY, show enhanced OER performance due to mixed Ni2+/Ni3+ valence states, providing new direction for high-performance OER materials.