Recent advances in metal-nitrogen-carbon catalysts for electrochemical water splitting

The urgent need for clean and renewable energy and environmental awareness have promoted extensive research into creating a future sustainable energy supply system. Water electrolysis, considered the most promising technology for hydrogen production, has attracted much attention. A series of metal-nitrogencarbon based heterogeneous electrocatalysts have been developed for HER and OER. Recent advances in this field are summarized here, including their structures, synthetic methods and especially highlighting the applications of several major kinds of catalysts in water splitting. Finally, the existing key challenges and research directions for enhancing performance are pointed out.