Efficient photocatalytic removal of typical water pollutants synergized by nitrogen defects and Fe-Ti alloy

Abstract

Transition metal ions and non-metal co-doped carbon-based materials have attracted extensive attention due to their unique properties and excellent catalytic effect. Fe₂O₃/TiO₂@Fe/Ti-N-C multifunctional photocatalyst with Fe-Ti alloy and abundant nitrogen defects was reported. The photocatalytic results showed that the removal rates of Cr (VI), Congo red (CR) and levofloxacin (LFX) in water by Fe₂O₃/TiO₂@Fe/Ti-N-C were 88.46, 96.71 and 99.06 %, respectively. The photoelectric test results show that bimetallic conjugated structure of Fe and Ti can effectively increase the light absorption range and accelerate the carrier separation. N-defects can significantly increase the lifetime and concentration of photogenerated holes, thereby improving the catalytic efficiency of the photocatalyst. The single factor experiments proved that the optimal pH for the degradation of Cr(VI), CR and LFX by Fe₂O₃/TiO₂@Fe/Ti-N-C was 1, 11 and 9, respectively. In addition, Ca²⁺ and Mg²⁺ promoted the degradation of Cr(VI) and inhibited the degradation of CR and LFX. SO₄^2- inhibited the degradation of Cr(VI) and promoted the degradation of CR and LFX. Cl^- inhibited the degradation of Cr(VI), CR and LFX. This study elucidates the mechanism of N-defects and bimetallic sites in photocatalytic reactions, and provides theoretical support for efficient removal of heavy metals and organic pollutants in water.