Enhanced photoreduction of U(VI) in solution by Ti3C2Tx/g-C3N4 composites

The enhanced transfer efficiency of electron from photocatalyst to U(VI) is crucial for U(VI) photoreduction. Herein, we developed porous 2D/2D Ti3C2Tx/g-C3N4 heterojunction structure through the pyrolysis gasification of urea during direct calculation of Ti3C2 nanosheet and urea. Ti3C2Tx/g-C3N4 hybrid displayed the exceptional photocatalytic performance, high reaction rate constant (k1 = 0.0228min-1) and rapid removal kinetics due to high photocatalytic activity, good chemical stability and highly efficient separation of photo-generated electron-hole pairs. According to quenching experiments and ESR analysis, the superoxide (.O2-) radicals played an important role in U(VI) photoreduction by Ti3C2Tx/g-C3N4. The higher efficient migration of photo-generated electrons from g-C3N4 to Ti3C2 co-catalyst was attributed to the tight interfacial interaction of –NHx of g-C3N4 with Ti3C2 via NHx-Ti chemical bonding, which increased the photoreduction of U(VI) into U(IV) by XPS analysis. The findings are crucial for designing g-C3N4-based catalysts by manipulating electronic structure for enhanced U(VI) photoreduction.