Bimetallic MIL-88/Polyaniline Hybrid Hollow Structure: In-situ Synthesis and Enhanced Oxygen Evolution Reaction at High Current Densities.

Abstract

Developing oxygen evolution reaction (OER) electrocatalysts in an efficient strategy, while maintaining high catalytic activity and stability under high current densities, remains a crucial problem. In this study, a bimetallic iron-cobalt phytic acid complex loaded with polyaniline hollow structure (FCP@PAn) was successfully constructed, via a progress of selective etching and surface modification in one step without high-temperature phosphating or carbonization. The as-obtained FCP@PAn required only 329 and 385 mV overpotentials at high current densities of 500 and 1000 mA cm-2, respectively, due to phytic acid and polyaniline incorporation and the coordinated effect of each component. Additionally, the FCP@PAn exhibited the lowest Tafel slope values of 44.6 mV dec-1 and was able to continuously operate for 120 h at 500 mA cm-2, displaying high catalytic activity and stability. Hence, the hollow structure of the conductive polymer and MOFs composites provided a new surface modification strategy for transition metal-based catalysts that are prone to dissolution or corrosion during the OER process, as well as for high current density applications.