2D MXene-derived 3D TiO2-NiCoPx hierarchical heterostructures for efficient water splitting

Achieving efficient electrocatalytic activity in two-dimensional (2D) MXene for advanced water splitting remains a significant challenge. In this work, 2D MXene was derived into sea urchin-like TiO2 and used to load porous bimetallic phosphide (NiCoPx) nanorods to achieve three-dimensional (3D) TiO2-NiCoPx hierarchical heterostructures. The hierarchical heterostructures synthesized through hydrothermal and phosphating processes enable rich heterogeneous interfaces and fully exposed active sites, thereby facilitating efficient charge transfer and accelerating mass transfer rates. As a result, the TiO2-NiCoPx heterostructures inherit the low overpotential (311 mV at 10 mA cm−2) and long-term stability (current density retention of 94.1 % after 12 h) towards oxygen evolution reaction (OER). Importantly, the assembled TiO2-NiCoPx || Pt/C cell also exhibits remarkable water splitting performance. This contribution delivers a desirable opportunity for constructing efficient 2D MXene-based electrocatalysts with abundant active sites for water splitting. [Display omitted] •Hydrothermal strategy is proposed to construct 2D MXene derivatives.•Porous NiCoPx nanorods are tightly anchored on sea urchin-like TiO2.•TiO2-NiCoPx hierarchical heterostructure exhibits excellent water splitting performance.