One-step chemical transformation synthesis of CoS2 nanosheets on carbon cloth as a 3D flexible electrode for water oxidation

Abstract

Water electrolysis is an important way to gain pure hydrogen, while it is restricted by the sluggish kinetics of oxygen evolution reaction. To improve hydrogen production capability, it is critical to search for low-cost, earth-abundant, and superior catalytic activity materials as electrocatalysts for water oxidation. Herein, one-step chemical transformation strategy is utilized to synthesize cobalt sulfide nanosheets supported on the carbon cloth through the sulfuration process of the Co3O4 precursor. The catalyst exposes abundant active sites and facilitates charge transfer, which is beneficial to water oxidation. In alkaline electrolyte, the catalyst as a non-noble metal electrode exhibits sparkly performance for water oxidation. To achieve current densities of 10 and 100 mA cm−2, the overpotentials as low as 291 and 364 mV are demanded, respectively. Moreover, cobalt sulfide nanosheets on the carbon cloth manifest a small Tafel slope of 69 mV dec−1 and robust long-term durability. In addition, this one-step chemical transformation strategy can be utilized to synthesize cobalt selenide nanosheets on the carbon cloth, providing an orientation for developing other binder-free electrocatalysts for water oxidation.