Facile synthesis of a novel Co–Ba–TPA MOF exhibiting nearly identical overpotential for electrochemical production of hydrogen and oxygen

Abstract

In this study, the successful synthesis and comprehensive characterization of a novel cobalt–barium–terephthalic acid metal–organic framework (Co–Ba–TPA MOF) as a high-performance bifunctional electrocatalyst is reported. The prepared MOF exhibits synergistic interactions between Co and Ba metal centers within the terephthalic acid framework to exhibit an optimized electronic environment for enhanced electrocatalytic performance. Structural characterization through XRD, SEM and FTIR confirmed successful framework formation, while electrochemical evaluation revealed exceptional bifunctional activity with almost identical overpotential across both water splitting half-reactions. The MOF demonstrates an overpotential of 414.5 mV and 412.6 mV at 10 mA cm⁻² for HER and OER maintaining a Tafel slope of 145.23 mV dec⁻¹ and 106.18 mV dec⁻¹, respectively. The OER performance is preserved up to higher current densities (e.g. 100 mA cm⁻²), which makes it possibly applicable for industrial applications. The almost identical overpotentials for both reactions represent a commendable achievement in bifunctional catalyst design by eliminating the typical trade-off between HER and OER activities shown by most single-metal catalysts and offering an alternative to expensive platinum-group metals while maintaining competitive electrocatalytic performance.