Nanostructured cobalt-based metal-organic framework/cadmium sulfide electrocatalyst for enhanced oxygen evolution reaction and anion exchange membrane-based water electrolysis: Synergistic effect

Abstract

Precious metal-free electrocatalysts are essential for green hydrogen using low-cost electrolysis technology for future power supply systems. In this regard, anion-exchange membrane (AEM) electrolysis is the technology of best choice due to its compactness and high efficiency. Here, we proposed a low cost electrocatalyst composed of cadmium sulfide (CdS) nanoparticles decorated in a Cobalt-based metal-organic framework (CdS/ZIF-67), synthesized using a simple coprecipitation method. Compared with pristine Cobalt-based metal-organic framework (ZIF-67), 5 wt%CdS/ZIF-67 has excellent electrochemical oxygen evolution reaction activity, low overpotential (294 mV), low Tafel-slope (100 mV dec(-1)), higher mass activity (25.8 mA mg(-1)), and better stability. The AEM electrolyzer with the 5 wt%CdS/ZIF-67 anode can attain a potential of 1.85 V at a current-density of 1 A cm(-2), which is lower than that of bare Cobalt-based metal-organic framework electrolyzers. Thus, these catalysts are not only very active but also scalable, making them a promising electrolyzer for application in commercial power market.