Cobalt sulfide aerogel prepared by anion exchange method with enhanced pseudocapacitive and water oxidation performances

This work introduces the anion exchange method into the sol-gel process for the first time to prepare a metal sulfide aerogel. A porous Co₉S₈ aerogel with a high surface area (274.2 m² g⁻¹) and large pore volume (0.87 cm³ g⁻¹) has been successfully prepared by exchanging cobalt citrate wet gel in thioacetamide and subsequently drying in supercritical ethanol. Such a Co₉S₈ aerogel shows enhanced supercapacitive performance and catalytic activity toward oxygen evolution reaction (OER) compared to its oxide aerogel counterpart. High specific capacitance (950 F g⁻¹ at 1 A g⁻¹), good rate capability (74.3% capacitance retention from 1 to 20 A g⁻¹) and low onset overpotential for OER (220 mV) were observed. The results demonstrated here have implications in preparing various sulfide chalcogels. (paper)