NiP2/FeP heterostructural nanoflowers interwoven by carbon nanotubes as highly efficient electrocatalyst for oxygen evolution reaction

Oxygen evolution reaction (OER) for water splitting has a sluggish kinetics, thus significantly hindering the reaction efficiency. So far, it is still challenging to develop a cost-efficient and highly active catalyst for OER processes. To address such issues, we design and synthesize NiP2/FeP heterostructural nanoflowers interwoven by carbon nanotubes (NiP2/FeP@CNT) by a hydrothermal reaction followed by phosphating. The NiP2/FeP@CNT catalyst delivers excellent OER performance: it displays an ultralow Tafel slope of 44.0 mV dec−1 and a relatively low overpotential of 261 mV at 10 mA cm−2, better than RuO2 commercial catalyst; it also shows excellent stability without observable decay after 20-h cycling. The outstanding OER property is mainly attributed to its special 3D stereochemical structure of CNT-interwoven NiP2/FeP heterostructural nanoflowers, which is highly conductive and guarantees considerable active sites. Such nanostructure greatly facilitates the charge transfer, which significantly improves its electrocatalytic activity. This work offers a simple method to synthesize non-precious transition metal-based phosphide electrocatalysts with a unique hierarchical nanostructure for water splitting.