Highly efficient photoelectrochemical water oxidation enabled by enhanced interfacial interaction in 2D/1D In2S3@Bi2S3 heterostructures

Abstract

van der Waals (vdW) heterostructures have received tremendous attention in low dimensional semiconductors due to interfacial surface reconstruction and electronic coupling effects. Here, we report mixed-dimensional 2D/1D In₂S₃@Bi₂S₃ heterostructures synthesized via a two-step solvothermal in situ growth. Theoretical calculations demonstrate that In₂S₃ nanosheets and Bi₂S₃ nanorods are integrated together through the vdW interaction. Through theoretical calculations and experiments, the results confirm that the surface potential of Bi₂S₃ is higher than that of In₂S₃, implying that the free electrons will flow from Bi₂S₃ to In₂S₃ when the two semiconductors come into contact, leading to electron and hole accumulation at the In₂S₃ and Bi₂S₃ surface. This redistribution of charges will induce an outward vector of a built-in electric field at the In₂S₃@Bi₂S₃ interface (from Bi₂S₃ to In₂S₃), thereby improving hole transfer to In₂S₃ and electron transfer to Bi₂S₃. The advanced heterostructure aids in shortening the photogenerated electrons' transport time (14 μs), promoting the electron–hole separation, and presents a 13.3-fold enhancement in photocurrent density when compared to In₂S₃.