Facile assembly of Ni(OH)2 nanosheets on nitrogen-doped carbon nanotubes network as high-performance electrocatalyst for oxygen evolution reaction

Highlights: • Three-dimensional N-CNTs were prepared on Ni foam by a CVD method. • The core-shell N-CNTs/Ni(OH)₂ nanosheets possess abundant active sites and high electronic conductivity. • The introduction of N-CNTs can remarkably improve the OER performance of the Ni(OH)₂ nanosheets. Developing non-noble metal-based electrocatalysts with cost-effective materials for water splitting is critical to clean energy generation and storage. However, the process of water splitting is greatly hindered by the oxygen evolution reaction (OER), which is kinetically sluggish and requires large overpotentials. Herein, we report an active and stable OER catalyst by electrodeposition of ultrathin Ni(OH)₂ nanosheets on three-dimensional interwoven nitrogen-doped carbon nanotubes (N-CNTs). The Ni(OH)₂ nanosheets grown on the N-CNTs afforded a current density of 10 mA cm⁻² at the overpotential of only 254 mV, smaller than the commercial IrO₂ catalyst. Moreover, the as-prepared catalyst shows long-term durability almost without degradation over 100 h. The excellent OER activity can be ascribed to the unique layered structure of Ni(OH)₂, the ultrathin and interconnected features of the nanosheets, and the three-dimensional (3D) porous conducting network of the N-CNTs. The rational design strategy can be extended to the preparation of other non-precious metal catalysts with enhanced OER performance.