Electrocatalysts for oxygen reduction and evolution reactions (ORR and OER) are essential for renewable energy technologies such as fuel cells or water splitting. The development of metal-free electrocatalysts to replace expensive precious-metal-based catalysts has generated much interest.

Bhalchandra Kakade and colleagues, SRM University, India, have developed a simple and cost-effective strategy to prepare a bifunctional electrocatalyst consisting of carbon nanotubes and boron nitride through a one-step hydrothermal method followed by annealing at 750 °C. The team studied the material in terms of morphology using transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). They also evaluated the catalytic performance using cyclic voltammetry and rotating ring-disk electrode measurements and compared it to the state-of-the-art precious-metal-based electrocatalyst, Pt/C.

This metal-free nanocomposite shows excellent activity towards both ORR and OER, most likely owing to a synergistic effect between the two components and the formation of ideal sites for oxygen adsorption with subsequent reduction. Additionally, the researchers were able to eliminate cross-over effects from undesirable methanol oxidation occurring in direct methanol fuel cells that would result in loss of electrocatalytic activity. The catalyst shows a high resistance against CO poisoning, which remains a considerable challenge for metal-based catalysts.

• Carbon Nanotube/Boron Nitride Nanocomposite as a Significant Bifunctional Electrocatalyst for Oxygen Reduction and Oxygen Evolution Reactions,
  Indrajit M. Patil, Moorthi Lokanathan, Balakrishnan Ganesan, Anita Swami, Bhalchandra Kakade,
  Chem. Eur. J. 2016.
  DOI: 10.1002/chem.201604231