In situ XPS demonstrated efficient charge transfer of ohmic junctions based on graphdiyne (g-CnH2n-2) nanosheets coupled with porous nanoflowers Ni5P4 for efficient photocatalytic H2 evolution

Abstract

The photocatalytic hydrogen evolution ability of catalyst can be effectively improved by constructing suitable heterojunction. The present study involves a new type of carbon-material semiconductor graphdiyne (GDY) was prepared by ball milling assisted reduction elimination reaction, and introduced into metal-rich Ni5P4 nanoflowers by hydrothermal method. GDY/Ni5P4 ohm junction was successfully constructed to regulate the electron direction. The C ≡C bond in GDY exhibits high reducibility, which is conducive to inhibiting the oxidation of Ni5P4. The unique porous nanoflower-like structure of Ni5P4 enables it to achieve complete contact with solvents, thereby enhancing proton absorption capabilities. The construction of an ohmic junction is confirmed to induce electron transfer from GDY to Ni5P4 through situ XPS characterization, thereby suppressing the recombination of electron-hole pairs in GDY. Among them, 15%GDY/Ni5P4 has the best photocatalytic hydrogen evolution activity of 11713.6 μmol h−1 g−1, which is about 15 times higher than that of GDY (755.4 μmol h−1 g−1) and 5 times that of Ni5P4 (2369.6 μmol h−1 g−1). This work provides a new way to construct ohm junction based on GDY for photocatalytic hydrogen evolution.