Partially oxidized MXenes-derived C-TiO/TiC coupled with Fe-CN as a ternary Z-scheme heterojunction: Enhanced photothermal and photo-Fenton performance.

Photo-Fenton reaction combining the photocatalytic reaction and Fenton reaction showed excellent degradation performance. However, it highly demanded the catalysts to display outstanding activity in these two reactions. Herein, Fe-doped carbon nitride/MXenes-derived C-TiO/TiC (Fe-CN/TiC/C-TiO) was prepared via two steps: Fe-CN and TiC were assembled via face-to-face attachment, following by in-situ partial oxidation of TiC to C-TiO. DFT predicted a Z-scheme charge transfer routine via metallic TiC as bridge, which was verified by EPR and radical trapping experiments. Additionally, PDOS calculation revealed the charge density around the doped-Fe atoms was remarkably increased, leading to better HO activation, which was experimentally confirmed by high yield of OH. Moreover, Fe-CN/TiC/C-TiO possessed the high photothermal effect to accelerate the surface reaction. By taking advantage of these merits, the degradation rate of Fe-CN/TiC/C-TiO was at least 4.2 times higher than the reference catalysts. Our work provided an insight toward the g-CN/TiO-based photo-Fenton catalysts with high performance.