Hierarchical nickel phosphide-MXene nanosheets composite as durable electrocatalyst for electrochemical hydrogen production via water-splitting

In this study, a thoroughly durable hydrogen evolution reaction (HER) electrocatalyst, nickel phosphide (NiP₂), was grown on conductive Ti₃C₂MXenes synthesized via a non-HF hydrothermal route. This approach utilizes MXenes as both a support and promoter to accelerate charge transfer, enabling efficient HER at a very low overpotential. A hydrothermal strategy was developed for the<i>in-situ</i>growth of NiP₂microflowers on Ti₃C₂sheets at low temperature. The improved delamination of MXenes achieved through this novel method facilitates the growth and intercalation of active electrocatalysts betwixt the 2d MXene sheets. High electrical conductivity of MXenes, coupled with the strong interfacial coupling between MXene sheets and NiP₂, significantly enhances the HER performance compared to pristine MXene or NiP₂alone. The as-prepared MXene-NiP₂composite demonstrates excellent stability and current density, achieving an overpotential of ∼70 mV, which is comparable to state-of-the-art Pt-based electrocatalysts. This strategy for constructing MXene-based heterostructures demonstrates the NiP₂/MXene composite as an outstanding candidate for electrolytic hydrogen production. Additionally, MXenes are highlighted as ideal conductive supports for the growth of other electrocatalysts, paving the way for the development of heterostructured materials with enhanced stability in various media, making the water-splitting process more cost-effective.