A crystalline/amorphous CoP@CoB hierarchical core–shell nanorod array for enhanced hydrogen evolution

Abstract

Highly active, durable and cost-effective catalysts toward the hydrogen evolution reaction (HER) are crucial for widespread use of electrochemical water splitting in hydrogen production. Herein, a hierarchical core–shell nanorod array (NRA) comprising an inner crystalline CoP nanorod and an outer amorphous CoB (a-CoB) nanosheet (CoP@a-CoB) is fabricated on conductive carbon cloth through a successive phosphidation–chronoamperometry–boronation strategy. The as-obtained catalyst exhibits excellent HER activity with low overpotentials of 56.3 and 81.2 mV at a current density of 10 mA cm⁻² in alkaline and acidic electrolytes, respectively. Furthermore, it exhibits superior long-term stability with almost no activity degradation. The outstanding HER electrocatalytic performance might be attributed to the unique hierarchical core–shell NRA structure with the crystalline CoP nanorod as the core and the amorphous CoB nanosheet as the shell, which could not only provide abundant active sites, but also guarantee effective electron transport. This work opens up a promising way to rationally design high-efficient electrocatalysts for hydrogen production.