The damage caused by water pollution has seriously affected human health, in which nitrate is difficult to remove effectively because of its stability and solubility in the water environment. Among the various technologies for nitrate removal, electrocatalytic conversion of nitrate to ammonia is one of the best choice because of its green and efficient nature as well as its ability to “turn waste into treasure”. In recent years, the development of high-performance electrocatalysts to promote the activity of electrocatalytic nitrate reduction ( NO3RR) has received extensive attention from researchers. Among various electrocatalytic materials for NO3RR, carbon-based catalysts have become a promising electrocatalyst due to the advantages of affordable price, controllable structure, excellent stability and exceptional reactivity. Focusing on the carbon-based materials, this review summarizes the research progress of carbon-based catalysts for NO3RR in recent years, including heteroatom-doped carbon-based catalysts as well as metal and metal oxide-loaded or modified carbon-based catalysts. Opinions on the current challenges and future research directions of carbon-based catalysts for NO3RR are also presented. This review hopes to provide some references and principles for the design and preparation of carbon-based catalysts for high-performanceNO3RR process.

Recent advances in carbon-based catalysts for electrocatalytic nitrate reduction to ammonia
    Abstract
    1 Introduction
    2 Basic principle of electrocatalytic NO3RR
        2.1 Reaction mechanisms
        2.2 Theoretical calculations
    3 Non-metallic carbon-based catalysts
        3.1 N doping
        3.2 F doping
        3.3 B doping
    4 Metal carbon-based catalysts
        4.1 Monometallic carbon-based catalysts
        4.2 Bimetallic carbon-based catalysts
        4.3 Other metal compounds or metal oxide carbon-based catalysts
    5 Challenges and outlook
    Acknowledgements 
    References

• Cuilian Sun(Key Laboratory of Novel Biomass‑Based Environmental and Energy Materials in Petroleum and Chemical Industry, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor &Green Chemical Technology, School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430205, China)
• Jin Li(Key Laboratory of Novel Biomass‑Based Environmental and Energy Materials in Petroleum and Chemical Industry, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor &Green Chemical Technology, School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430205, China)
• Wei Xiong(Key Laboratory of Novel Biomass‑Based Environmental and Energy Materials in Petroleum and Chemical Industry, Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor &Green Chemical Technology, School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430205, China) Corresponding author
• Xiujing Xing(Chemistry Department, University of California, Davis, CA 95616, USA)
• Hao Li(Advanced Institute for Materials Research (WPI‑AIMR), Tohoku University, Sendai 980‑8577, Japan)