MOF-Templated Synthesis of Three-Dimensional B-Doped NiCoP Hollow Nanorod Arrays for Highly Efficient and Stable Natural Seawater Splitting

Seawater electrolysis represents a sustainable route for the mass production of high-purity hydrogen fuel. However, the sluggish kinetics of the cathodic hydrogen evolution reaction (HER) remains an excellent challenge for large-scale applications, especially in industrial-level current densities. Here, we report a general strategy to activate three-dimensional (3D) NiCoP hollow nanorod arrays through boron doping, creating high-valence metal centers that are favorable for the water dissociation step. It has been found that the 3D B-NiCoP hollow nanorod arrays can drive a cathodic current density of 10 mA cm–2 at an overpotential of 90, 90, and 98 mV in alkaline freshwater, alkaline simulated seawater, and alkaline natural seawater electrolytes, respectively. The 3D B-NiCoP hollow nanorod array electrocatalyst manifests excellent long-term stability under a high current density of 113 mA cm–2 for more than 85 h in freshwater and seawater electrolytes. Moreover, the 3D B-NiCoP hollow nanorod array electrocatalyst exhibits outstanding HER activity and stability in natural seawater. The study reveals that the exceptional performance for HER is attributed to the high-valence metal centers catalyst, abundant active sites, and efficient charge transfer of the unique 3D structure. This work provides a powerful strategy for designing cost-efficient electrocatalysts for seawater electrolysis.