Self‐Assembled CoFe Nanoparticle‐Embedded Carbon Nanowires as Efficient Nonprecious Catalyst for Overall Water Splitting

Abstract

At present, it is still challenging to develop nonprecious transition metal‐based electrocatalysts with a high efficiency and stability for overall water splitting. To address such issues, for the first time, a novel nonprecious hybrid electrocatalyst—a self‐assembled CoFe nanoparticle‐embedded porous carbon nanowires (CoFe@CNWs)—is designed and synthesized via a facile hydrothermal reaction and subsequent annealing process. This hybrid electrocatalyst demonstrates an outstanding performance for oxygen evolution reaction (OER) with a very small Tafel slope of 63 mV dec−1 and an ultralow onset overpotential of 170 mV; particularly, when the hybrid is used for overall water splitting, the cell voltage is as low as 1.69 V at a current density of 10 mA cm−2. The excellent electrocatalytic performance of CoFe@CNWs is attributed to its unique porous nanoarchitecture, constructed by ultrasmall conductive CoFe nanoparticles homogenously embedded in highly conductive CNWs, which would not only guarantee abundant catalytic sites and structural stability but also facilitate electron transportation, resulting in a significant improvement in the electrocatalytic performance. This work provides a strategy to rationally design and synthesize a nanostructured transition metal‐based hybrid to be used as a highly effective and stable nonprecious electrocatalyst for overall water splitting.