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

In this work, oxygen vacancy‐rich C/TiO_{2} (OV‐C/TiO_{2}) samples are prepared by a one‐step calcination approach using Ti_{3}C_{2} MXene as the precursor, and used for the photocatalytic N_{2} reduction. The NH_{3} yields of all the prepared OV‐C/TiO_{2} samples exceed those achieved on commercial anatase TiO_{2} and P25, with both H_{2}O and CH_{3}OH as the proton sources. Among them, the OV‐C/TiO_{2}‐600 offers the remarkable NH3 synthesis rates, which are 41.00 µmol g^{−1} h^{−1} (with CH_{3}OH as the proton source). The photocurrent and fluorescence spectra show that OV‐C/TiO_{2}‐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 N_{2} on the surface of the prepared OV‐C/TiO_{2}‐600 than that on the surface of the commercial anatase TiO_{2}. Moreover, DFT calculations further demonstrate that N2 conversion to NH_{3} through a Gibbs free energy release leading alternating pathway with a low energy barriers, on the oxygen vacancy on TiO_{2} surface.