Non-precious cobalt oxalate microstructures as highly efficient electrocatalysts for oxygen evolution reaction

Abstract

Well-defined cobalt oxalate (CoC₂O₄·2H₂O) microstructures with controllable morphologies have been successfully synthesized by a simple solvothermal process. The resulting CoC₂O₄·2H₂O microrods (MRs) and micropolyhedrons (MPs) can be easily controlled by rationally tuning the composition of solvents. It is experimentally demonstrated that CoC₂O₄·2H₂O microstructures as nonprecious metal based electrocatalysts exhibit remarkable activity for catalyzing OER in alkaline medium. Such performance is found to be closely dependent on the morphology of CoC₂O₄·2H₂O microstructures. The MRs with higher aspect ratio and more active Co sites manifest a small OER onset potential, large anodic current and long-term durability, which are superior to the MPs, derived Co₃O₄ MRs, and previously reported cobalt oxalate electrocatalysts, and even compare favorably with most previously reported Co-based OER electrocatalysts.