The synergistic effect of NiCo nanoparticles and metal organic framework: Enhancing the oxygen evolution reaction of carbon nanohorn-based catalysts

Abstract

Enhancing the reactivity of nanocatalysts by the synergistic effect of MOF derivatives active nanoparticles (NP) and Metal organic framework (MOF) supported by carbon materials is a state of the art progress. Herein, a strategy for surface-mounting NP/NiCo MOF thin films on Carbon nanohorn (CNH) by controlled pyrolysis is developed. CNH is introduced to improve the conductivity and structure stability of MOF and polydopamine (PDA) is used to bond each other, resulting in CNH@PDA@MOF. Compared with CoMOF@PDA@CNH, the introduction of Ni helps to waken the bonding between the metal center (Co) and the coordination solvent and expose more unsaturated coordination centers and in turn the catalytic activity. As a result of synergistic effect on geometric and electronic structure of bimetallic center Ni and Co codes in MOF, Ni1Co4MOF@PDA@CNH shows the best catalytic activity and was further used as both the source of the framework structure and the precursor of active NP derivatives. By partial pyrolysis of MOF, the active NP/MOF/CNH can be successfully obtained at 400 ℃. The hierarchically structured NP/MOF/CNH as a synergistic electrocatalyst shows excellent activity (216 mV/cm2 at a current density of 10 mA/cm2), exceeding most previously reported bi-metallic catalysts. Obviously, the combination of NiCo NPs, partially degraded MOF and CNH makes an improvement in the increase of active species, promotion of water adsorption, and electron transfer. This universal and productive method grappling conductive active sites/porous MOF on CNH plays an important role in construction of synergistic electrocatalysts for OER.