In situ XPS proved interfacial charge separation of S-scheme graphdiyne/β-AgVO3 heterojunction for enhanced photocatalytic hydrogen evolution

Abstract

Application of graphdiyne (GDY) in photocatalysis remains significant challenges. Herein, a 1D/2D S-scheme GDY/β-AgVO3 heterojunction was successfully constructed by β-AgVO3 nanorods anchored on GDY nanosheets for high efficiently photocatalytic hydrogen evolution. The GDY nanosheets were fabricated by a convenient mechanical ball milling method. The S-scheme GDY/β-AgVO3 heterojunction possesses a close interface with oriented built-in electric-field for efficient extraction of photocarriers from the conduction band of β-AgVO3 to valence band of GDY. The 25 % GDY/β-AgVO3 exhibited outstanding photocatalytic H2 generation capacity of 14.15 mmol g−1 h−1, which was 17.26 and 11.99 folds greater than that of GDY and β-AgVO3, respectively. The improved hydrogen evolution efficiency can be given the credit to the establishment of a built-in electric field between GDY and β-AgVO3, which causes the photogenerated electrons to move directionally following the path of the S-scheme. In addition, GDY showed full spectrum absorption characteristics, and the introduction of GDY into β-AgVO3 improved the photosensitivity of the catalyst, thus improving the solar energy utilization efficiency. The S-scheme mechanism is certified by in-situ XPS and density functional theory (DFT). The charge density difference of GDY/β-AgVO3 is further proved the photogenerated electrons of the GDY/β-AgVO3. This work provided an effectual approach for constructing graphdiyne-based S-scheme heterojunction with oriented built-in electric-field for efficient photocatalysis.