Assembling flower-on-sheet CoP–NiCoP nanohybrids as efficient self-supported electrocatalysts for hydrogen evolution reaction in both acidic and alkaline media

Self-supported electrocatalysts are directly employed as electrodes for water splitting. Herein, we report an effective strategy to develop flower-on-sheet structured nanohybrids, where CoP nanoflowers are epitaxially grown along the edges of Ni-Co-P nanosheets (namely NiCoP) on carbon cloth (m-CoP–NiCoP/CC), thus obtained as efficient self-supported electrodes for the hydrogen evolution reaction (HER) in both acidic and alkaline media. This unique nanostructure endows NiCoP nanosheets with maximal exposed surface area, along with increased active sites brought by CoP nanoflowers. Moreover, due to good electrical connection between CoP nanoflowers and NiCoP, and between conductive NiCoP and carbon cloth, electrons can easily transfer from active sites to the conductive substrates. Therefore, the m-CoP–NiCoP/CC exhibits superior catalytic activity and stability for HER in both acidic and alkaline media. The as-prepared electrocatalyst requires overpotentials of only 75.0–81.5 mV to deliver a benchmark current density of 10 mA cm −2 in acidic and alkaline media, respectively, which are superior to most of the previously reported metal phosphides-based electrocatalysts. Hence, this work can provide a design for developing highly active electrocatalysts for water splitting. Graphical abstract The self-supported CoP-NiCoP nanohybrids were prepared as efficient and durable electrocatalysts for hydrogen evolution reaction in both acidic and alkaline media, where CoP nanoflowers are epitaxially grown along the edges of NiCoP nanosheets.