Photocatalytic reduction of CO2 into fuels offers a promising avenue to tackle present energy challenges and mitigate global warming. At present, TiO2 has been widely used in photocatalytic CO2 reduction reactions, and element doping can optimize the band structure of TiO2 to improve the efficiency of photocatalytic CO2 reduction. In this work, TiO2 doped with different content of N was prepared using TiN as the precursor through a simple one-step calcination method. Under optimized conditions, the optimal CO yield of the modified photocatalyst is 41.1 μmol g− 1 h− 1, which is 8 times higher than that of p25 type TiO2. Density functional theory (DFT) calculations confirmed that N-doping can reduce the band gap of TiO2 and decrease the Gibbs free energy of CO2 reduction reaction. In-situ-XPS indicated that N-doping can enhance the activation of CO2 by enriching photo generated electrons. Additionally, In-situ-FTIR spectra were employed to detect intermediates and track variations in the consumption of H2O and CO2, providing deeper insights into the mechanism responsible for enhancing efficiency. Our work addresses the deficiencies of the past and provides more detailed theoretical insights for the accelerated photocatalytic reduction of CO2 by N-doping TiO2.

N-doping of TiO2 for enhanced CO2 photocatalytic reduction and research on reaction mechanisms
    Abstract
    1 Introduction
    2 Experimental section
        2.1 Materials
        2.2 Preparation of N-TiO2
        2.3 CO2 Photoreduction experiments
        2.4 Photo-electrochemical measurements
        2.5 Theoretical calculation method
        2.6 Characterizations
    3 Results and discussion
    4 Conclusion
    Acknowledgements 
    References

• Jun Zhang(School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Wei Wang(School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Yue Yang(School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Yan Yan(School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Yongsheng Yan(School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China)
• Zhi Zhu(School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China, Jiangsu Chunlan Clean Energy Academy Co., Ltd., Taizhou 225300, People’s Republic of China, Department of Biology, Hong Kong Baptist University, Kowloon Tong 999077, Hong Kong, People’s Republic of China) Corresponding author