Large-scale fabrication of ZIF-derived electrocatalysts for industrial oxygen evolution

Abstract

The laboratory-scale catalyst synthesis is far from reaching the expectations of industrial-scale water electrolysis, and the bottleneck is the large-scale preparation of electrocatalysts. Herein, a cheap, efficient, and durable electrocatalyst (Mo–Co–O-ZIF) with two-dimensional nanosheet arrays in situ grown on pre-oxidized nickel foam is successfully synthesized through a time and energy-saving strategy. Significantly, this facile method is easy to scale up to produce 600 cm²-sized self-supporting electrodes with excellent reproducibility of both catalytic activity and microstructure. Since the well-designed nanosheet array structure has hydrophilic and oxygen-repellent properties, it provides a large active area and fast electron/mass transport during the catalytic oxygen evolution reaction. As a result, optimized Mo–Co–O-ZIF achieves an ultralow overpotential of 375 mV at 100 mA cm⁻² and a small Tafel slope of 56.1 mV dec⁻¹. Particularly, Mo–Co–O-ZIF exhibits long-term durability at high current densities, which has great significance for industrial oxygen production. The mechanism of excellent catalytic activity and stability are also systematically elucidated by systematic characterizations and electrochemical measurements. This study presents a methodology that enables the development of efficient and scalable electrocatalysts for industrial water electrolysis, resulting in significant time and energy savings.