Interface-driven synergy in NiSe-NiP@NF: A crystal-amorphous heterostructure for superior bifunctional catalysis

Efficient and durable bifunctional electrocatalysts are crucial for water splitting, however, optimizing their electronic structures remains a significant challenge. In this study, a self-supported electrocatalyst (NiSe-NiP@NF) with a crystalline-amorphous coupled heterostructure was synthesized via stepwise electrodeposition. The crystalline NiSe phase enhances electron transport owing to its high conductivity and metallic properties, which facilitate efficient charge transfer during catalysis. Moreover, it facilitates water dissociation by providing a conductive pathway. The amorphous NiP phase, abundant in active sites, accelerates the adsorption and conversion of reaction intermediates (e.g., *OH and *OOH) during the oxygen evolution reaction (OER). The synergy between the crystalline and amorphous phases enhances the overall electrochemical performance. NiSe-NiP@NF exhibits overpotentials of 265 mV for OER and 106 mV for HER at 10 mA·cm⁻ 2 , demonstrating excellent stability (99.2 % retention after 70 hours at 15 mA·cm⁻ 2 ). These findings emphasize the critical role of crystalline-amorphous coupling in enhancing electrocatalytic performance for efficient energy conversion.