Photocatalytic Nitrogen Reduction by Ti₃C₂ MXene Derived Oxygen Vacancy‐Rich C/TiO₂

Abstract In this work, oxygen vacancy‐rich C/TiO₂ (OV‐C/TiO₂) samples are prepared by a one‐step calcination approach using Ti₃C₂ MXene as the precursor, and used for the photocatalytic N₂ reduction. The NH₃ yields of all the prepared OV‐C/TiO₂ samples exceed those achieved on commercial anatase TiO₂ and P25, with both H₂O and CH₃OH as the proton sources. Among them, the OV‐C/TiO₂‐600 offers the remarkable NH₃ synthesis rates, which are 41.00 µmol g⁻¹ h⁻¹ (with H₂O as the proton source) and 84.00 µmol g⁻¹ h⁻¹ (with CH₃OH as the proton source). The photocurrent and fluorescence spectra show that OV‐C/TiO₂‐600 exhibit the highest generation/separation rate and longest lifetime of photocarriers among all the prepared samples. ESR and TPD experiments confirm much more efficient chemisoption of N₂ on the surface of the prepared OV‐C/TiO₂‐600 than that on the surface of the commercial anatase TiO₂. Moreover, DFT calculations further demonstrate that N₂ conversion to NH₃ through a Gibbs free energy release leading alternating pathway with a low energy barriers, on the oxygen vacancy on TiO₂ surface.