Photocatalytic Nitrogen Reduction by Ti<sub>3</sub>C<sub>2</sub> MXene Derived Oxygen Vacancy‐Rich C/TiO<sub>2</sub>
Jing Qian, Sen Zhao, Wenqiang Dang, Yuan Liao, Wen Zhang, Hui Wang, Lingling Lv, Lei Luo, Haiying Jiang, Junwang Tang
Abstract
Abstract 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 NH 3 synthesis rates, which are 41.00 µmol g −1 h −1 (with H 2 O as the proton source) and 84.00 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 N 2 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.