Sulfurizing-Induced Hollowing of Co9S8 Microplates with Nanosheet Units for Highly Efficient Water Oxidation.

Transition metal-based compounds are promising alternative nonprecious electrocatalysts for oxygen evolution to noble metals-based materials. Nanosheet-constructed hollow structures can efficiently promote the electrocatalystic activity, mainly because of their largely exposed active sites. Herein, hierarchical Co9S8 hollow microplates with nanosheet building units are fabricated via sulfurization and subsequent calcination of preformed Co-glycolate microplates. Benefiting from the advantages of a hollow structure, nanosheet units and high Co3+ content, Co9S8 hollow microplates exhibit remarkable catalytic property for oxygen evolution reaction (OER) with low overpotential of 278 mV to reach a current density of 10 mA cm-2, a low Tafel slope of 53 mV dec-1, and satisfied stability. This construction method of Co9S8 hierarchical hollow microplates composed of a nanosheet structure is an effective tactic for promoting OER performance of water splitting electrocatalysts.