Electrocatalysis of oxygen reduction on heteroatom-doped nanocarbons and transition metal-nitrogen-carbon catalysts for alkaline membrane fuel cells

Over the last decade, great progress has been made in the development of non-precious metal catalysts for the electrochemical oxygen reduction reaction (ORR). Among these, heteroatom-doped carbon nanomaterials and transition metal-nitrogen-carbon (M-N-C) catalysts are especially advantageous in an alkaline environment, showing high electrocatalytic activity for the ORR and good durability. Over the past few years, substantial achievements have also been made in improving the performance of anion exchange membrane fuel cells (AEMFCs) and the commercialisation of these devices has emerged as a viable option. This review article provides an outline to the most relevant studies of the ORR on heteroatom-doped nanocarbons and M-N-C type catalysts in alkaline media. In addition, an overview of the studies employing these materials as cathodes in AEMFCs is presented. A separate section is devoted to the results obtained with alkaline direct methanol and ethanol fuel cells. Further perspectives in the field of AEMFC research and development are also highlighted. Electrochemical oxygen reduction behaviour and AEMFC performance using non-precious metal cathode catalysts are reviewed.