Boosting oxygen evolution with electrodes composed of metal sulfides and hydrogen bonded organic frameworks

Abstract

The development of effective and durable electrocatalysts for overall water splitting is needed to obtain clean and stable energy resources. The oxygen evolution reaction (OER) is a crucially constraining reaction in electrocatalytic water splitting due to its sluggish kinetics. Transition metal sulfides have been regarded as electrocatalysts for the OER due to their remarkable characteristics such as high intrinsic activity, exceptional stability, and excellent electrical conductivity. Herein, we report a new electrode composed of metal sulfides and hydrogen-bonded organic frameworks (HOFs) that was constructed by melamine trithiocyanuric acid (MTC). The sulfides of cobalt and iron are in situ formed when preparing MTC by using the hydrothermal method. The sulfides in MTC boosted the electrocatalytic performance; a remarkably low overpotential value of 130 mV at a current density of 100 mA cm⁻² was achieved; the Tafel slope was measured to be 45 mV dec⁻¹, indicating the excellent catalytic performance of the composites as compared to the bare MTC. Additionally, these materials exhibited remarkable stability under alkaline conditions, further highlighting their potential as catalysts in electrocatalytic applications. Our prepared samples exhibited superior OER performance compared to expensive benchmark electrocatalysts made of IrO₂ and numerous other reported electrocatalysts. The design of these materials, which are based on hydrogen-bonded organic frameworks, will pave a new way for the development of highly desirable electrocatalysts for electrocatalytic water splitting.