Ultrathin CoTe nanoflakes electrode demonstrating low overpotential for overall water splitting

Abstract Hydrogen production by electrocatalytic water splitting is of supreme significance for revolving the energy crisis at hand, and developing highly efficient, robust and cost-effective electrocatalyst materials is a challenging task on the way. Herein, we present unique three-dimensional (3D) ultrathin cobalt telluride nanoflakes (CoTe-NF) as single electrocatalyst with exceptionally high bifunctional activity both for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The hydrothermally synthesized CoTe material exhibits nanoscale and highly porous structural morphology and characterized by various techniques. For OER, the CoTe 3D electrode demonstrates a low onset potential of 1.44 V vs RHE with Tafel slope value of 66 mV dec−1 indicating a proton coupled electron transfer (PCET) mechanism and well-balanced kinetics. On the other hand, the electrocatalyst also executes HER at low onset potential of 0.07 V vs RHE with a modest Tafel slope of 143 mV dec−1. The materials also showed excellent stability. This work may also reveal valuable insights for developing cost-effective, efficient and low overpotential single electrocatalyst executing overall water splitting using 3D architecture Co-chalcogenide precursors posing a great alternative to noble-metals derived materials.