Synergistic design of ZIF-67/Sn-doped NiFe-LDH for enhanced oxygen evolution reaction

Abstract

The development of efficient and cost-effective oxygen evolution reaction (OER) catalysts is critical for advancing water-splitting technologies. In this study, we report the synthesis of a Sn-doped NiFe layered double hydroxide (LDH) integrated with zeolitic imidazolate framework-67 (ZIF-67)-derived Co species (NiFe-LDH-Sn/ZIF-67) as an efficient catalyst for the OER. The doping of Sn into NiFe-LDH enhances the electronic conductivity and optimizes the active sites for the OER. Concurrently, the introduction of ZIF-67 promotes structural stability and increases the surface area to 727 m² g⁻¹, fostering synergistic interactions between the components. The NiFe-LDH-Sn/ZIF-67 catalyst exhibits a significantly lower potential of 1.59 V vs. RHE at 10 mA cm⁻² and a Tafel slope of 79 mV dec⁻¹ in alkaline media. The study reveals that Sn doping facilitates the electron transfer process by reducing the equivalent series resistance (ESR) from 325 Ω to 161 Ω, while ZIF-67 improves charge redistribution and catalytic stability by 91.8% after 24 h. This study underscores the potential of combining LDH and metal–organic frameworks to design advanced catalysts for sustainable energy applications.