Electrochemical reduction of carbon dioxide to valuable chemicals is a promising way of storing renewable energy through electric-to-chemical energy conversion, while its large-scale application is in urgent need of cheap and high-performance catalysts. Herein, we invent a convenient method to synthesize N-doped porous carbon by ammonia etching the pyrolysis carbon of petroleum pitch. We found the ammonia etching treatment not only increase the pyridinic-N content, but also enlarge the specific surface area of the petroleum pitch-based porous carbon. As a cheap and easily available catalyst for carbon dioxide electroreduction, up to 82% of Faradaic efficiency towards carbon monoxide was obtained at − 0.9 V vs the reversible hydrogen electrode in 0.1 M KHCO3. After a long time electrocatalysis of more than 20 h, the Faradaic efficiency of carbon monoxide remains 80%, indicating the porous carbon as made have an ultra-high stability as catalyst for carbon dioxide reduction. Our work provides a new technology to economically prepare efficient electrocatalysts for carbon dioxide reduction.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials and reagents
        2.2 Synthesis of carbon materials
        2.3 Materials characterization
        2.4 Electrochemical measurements
        2.5 Analysis of products
    3 Results and discussion
    4 Conclusion
    Acknowledgements 
    References

• Hui Ning(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Zhihao Guo(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Wenhang Wang(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Xiaoshan Wang(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Zhongxue Yang(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Zhengguang Ma(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Yangming Tian(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Chenghao Wu(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))
• Jian Hao(State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University)
• Mingbo Wu(State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering, College of New Energy, Institute of New Energy, China University of Petroleum (East China))