Unravelling the interfacial charge migration pathway at atomic level in 2D/2D interfacial Schottky heterojunction for visible-light-driven molecular oxygen activation

Abstract Visible-light-driven molecular oxygen activation (MOA) is deemed as the potential route to enhance oxidation capacity of molecular oxygen, while activation efficiency is significantly impeded thanks to the deficient charge carrier separation and transfer. In this work, an atomic scale 2D/2D Schottky heterojunction is prepared using titanium carbide as 2D platform for in situ growth of 2D ultrathin bismuth molybdate nanosheet through anaerobically hydrothermal conditions. This 2D/2D Schottky heterojunction displays high performance for MOA, which is 5.56-fold higher than pristine one. The excellent activation efficiency is originated from ultrahigh charge carrier transfer channel, in which the surface charge transfer efficiency is enhanced (30.73 % vs 18.45 %) and the surface recombination constant is decreased (0.0019 s−1 vs 0.0031 s−1) compared to pristine one. The mechanism of photocatalytic MOA is unearthed based on experiment results and various characterizations. This study shows the great potential of atomic scale 2D/2D Schottky heterojunction in photocatalytic MOA.