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.