One-step hydrothermal formation of porous N-graphyne decorated TiO2/Ti3C2 composites with enhanced photocatalytic activity

Abstract

Herein, a series of porous N-graphyne decorated TiO2/Ti3C2 composites (NHGTTC-x) are constructed via hydrothermal treatment of N-graphyne and Ti3C2 in the presence of H2O2. The added H2O2 can serve as both pore-forming reagent of N-graphyne and oxidant of Ti3C2 in the synthesis process. As a result, numerous TiO2 nanoparticles in-situ generate on almost the entire surface of Ti3C2, and the porous wrinkled N-graphyne surrounds or attaches on the surface of TiO2/Ti3C2. The highest NH3 yield is found over the photocatalysis of NHGTTC-1% under UV–visible light for 4 h (0.306 mmol g−1), which is 3.86 times of that for pristine TiO2/Ti3C2 (0.079 mmol g−1). Moreover, the photodegradation efficiencies of tetracycline, rhodamine B, and levofloxacin by NHGTTC-1% are 2.40 folds, 2.58, and 7.90 times greater than that of pristine TiO2/Ti3C2 under visible light illumination. In addition, the primary active species is established to be superoxide radical (·O2−) in the photocatalytic decomposition process. Additionally, the enhanced mechanism of photocatalysis is methodically investigated by photocurrent, Tafel plots, electrochemical impedance, Mott-Schottky curves, etc. This study marks the first construction of porous N-graphyne/TiO2/Ti3C2 composites, which show superior photocatalytic activity for contaminants degradation and nitrogen fixation.