Simple 2 D/0 D CoP Integration in a Metal-Organic Framework-Derived Bifunctional Electrocatalyst for Efficient Overall Water Splitting

Non-noble metal-based bifunctional electrocatalysts are highly desired for water electrolysis. However, constructing a water electrolyzer using a sole catalyst without compromising either its oxygen evolution reaction (OER) or hydrogen evolution reaction (HER) performance is still challenging. In this study, a simple strategy is developed to integrate 2 D and 0 D CoP in the same metal-organic framework precursor-derived hollow N-doped carbon nanotube-assembled polyhedron (HNCNP). The unique hierarchical structure endows the resulting nanocomposite with both the advantages of more exposed active sites for 2 D and large surface-to-volume ratio for 0 D materials, whereas the hollow interior could benefit the charge and mass transfer properties. Thus, CoP/HNCNP@2 D CoP exhibits outstanding OER and HER activity and a low cell voltage when employed as both the anode and cathode in a two-electrode water electrolyzer. The approach of integrating the same metal phosphide phase with diverse dimensions may inspire new ways to design hierarchical nanostructures for advanced energy conversion applications.