Directly converting metal organic framework into designable complex architectures with rich co-arranged active species for efficient solar-driven water splitting

Abstract

Metal organic frameworks (MOFs) possess large specific surface areas, tunable composition, uniform metal active sites, and open framework structures, showing significant perspective in solar-to-chemical energy conversion. As we already know, Co-based ZIF-67 dodecahedron can be converted to functional Co3O4 and CoP frameworks through annealing means in air or an inert atmosphere. Interestingly, ZIF-67-derived Co3O4 is a typical p-type semiconductor but CoP is an n-type semiconductor. Here, a facile strategy is carried out to evolve polyhedral ZIF-67 with poor photocatalytic reaction toward designable complex architectures for efficient solar-driven water splitting. Specifically, one-step construction of complex functional Co3O4@CoP architecture was successfully implemented firstly in this work, that is, ZIF-67 polyhedrons were transformed into all-in-one Co3O4@CoP frameworks possessing the co-arranging of Co3O4 with CoP species in space, demonstrating the state-of-the-art green processes to construct designable complex architecture based on MOFs. More importantly, the ZIF-67-derived Co3O4@CoP photocatalyst exhibits more excellent photocatalytic water splitting performance in comparison with ZIF-67-derived CoP and Co3O4 as well as previous-best catalysts under identical conditions because of multi-action mechanism synergy. Additionally, the action mechanism about metal phosphides in H2 evolution reaction is revealed more thoroughly by the assistance of DFT and Zeta potential analysis.