N-enriched porous carbon encapsulated bimetallic phosphides with hierarchical structure derived from controlled electrodepositing multilayer ZIFs for electrochemical overall water splitting

Cost-effective transition metal-carbon-based hybrids have been widely dedicated to water splitting. Herein, a new three dimensional N-enriched holey carbon layers encapsulated bimetallic phosphides (CoNiP@CN) was synthesized by in situ growth, pyrolysis and phosphorization of CoNi mixed zeolite imidazole frameworks (ZIFs)@ZIF-8 films on Ni foam. CoNiP@CN/NF exhibited smaller overpotentials, lower charge transfer resistance and considerable stability for electrocatalysis. The better performance was attributed to the high conductivity of bimetallic phosphides and N-doped porous carbon, the maximum utilization of active sites on 3D conductive substrate and the protection of bimetallic phosphides by N-doped carbon layers. As an integrated high-performance non-noble electrocatalyst for overall water splitting, the CoNiP@CN/NF requires only 1.59 V@30 mA cm(-2) in alkaline solution, which is comparable to many other non-noble metal catalysts. This work highlights the construction highly efficient transition metal-carbon-based electrocatalyst derived from well-defined ZIF precursor, promoting the development of low-cost non-noble metal hybrids in energy chemistry.