N-functionalized hierarchical carbon composite derived from ZIF-67 and carbon foam for efficient overall water splitting.

[Display omitted] • An inexpensive and facile approach to synthesize a bimetallic electrocatalyst. • Carbon foam physically mixed with ZIF-67 generates Co-Zn-CNTs after pyrolysis. • The Co-Zn-CNTs demonstrate remarkable catalytic activity towards OER and HER. • Co 3 ZnC species contribute to the excellent performance of the electrocatalyst. • Co 3 ZnC species are associated with enhanced durability. An efficient and facile approach to synthesize a bi-functional electrocatalyst via combining carbon foam with cobalt-centered zeolitic imidazolate framework (ZIF-67) is reported. The carbon foam was synthesized via dehydration of sugar utilizing zinc nitrate, forming Co 3 ZnC in the carbon matrix. To obtain Co hybridized and Co particles covered with carbon nanotubes embedded in a carbon matrix (Co-Zn-CNTs), physical mixing of both defines the critical point after pyrolysis. Higher content of N-related species and transition metal species in polyvalent states and well-grown multi-wall carbon nanotubes for charge transfer are achieved after the pyrolysis process. The obtained Co-Zn-CNTs catalyst was employed as cathode and anode for overall water splitting (HER and OER) and showed excellent performances. This development offers a low-cost and straightforward strategy to synthesize catalyst material for large-scale fuel cells and water splitting technologies. This development affords a precise method for effectively improving the electrocatalyst performance derived from the ZIF-67 precursor. [ABSTRACT FROM AUTHOR]