Enhancing One-Dimensional Charge Transport in Metal-Organic Frameworks Hexagonal Nanorods for Efficient Electrocatalytic Oxygen Evolution Reaction.

Abstract

Metal-organic frameworks (MOFs) have exhibited huge potential in electrocatalytic fields. However, the intrinsic low conductivity and the blockage of metal active sites by organic linkers still seriously hinder their large-scale application. Here, as a proof of principle, we demonstrate that constructing cofacial π-π stacking in terminal ligand (4,4 -bipyridine) of a Ni/Fe-chain-based MOF to fabricate strong π-π interaction, in combination with unique hexagonal nanorods (HXR) structure is an effective strategy to enhance the one-dimensional charge carrier efficiency and thus achieve excellent OER activity. The approach yields a high TOF value (4.54 s -1 ) in well-designed bimetallic chain-based MOFs (NiFe-HXR) at the overpotential of 350 mV, which is about 8.7 and 34.9 times higher than those in Ni-HXR (0.52 s -1 ) and IrO 2 (0.13 s -1 ), respectively. This work effectively combines through-bond channel in chain-based structure of NiFe-HXR and through-space transport between face-to-face terminal ligands, thus resulting in outstanding OER activity. This novel strategy of integrating MOFs structure chemistry and morphology modulation to promote OER may open a new perspective to synthesize MOFs toward energy relevant electrochemical reactions.