Construction of electron transport channels in type-I heterostructures of Bi2MoO6/BiVO4/g-C3N4 for improved charge carriers separation efficiency

Abstract

In this work, flower-like Bi2MoO6 nanoparticles grown on FTO substrates were firstly fabricated using a seed-free hydrothermal method. The Bi2MoO6 nanoflowers exhibited, to the best of our knowledge, higher photoelectrochemical (PEC) performances than other previously reported morphologies. It is generally accepted that the formation of type-I heterostructures is unfavorable for PEC applications. Nevertheless, in this work, we have successfully constructed a novel type-I architecture with numerous electron transport channels. In this unique Bi2MoO6/BiVO4 structure, BiVO4 films were continuously distributed on both the surfaces and the interstices of Bi2MoO6 nanoflowers. Interconnected BiVO4 nanoparticles could intimately contact with FTO substrates and thus constitute the electron transport channels, which could promptly transfer electrons to FTO substrates. Simultaneously, a cocatalyst of g-C3N4 was modified on the surfaces of BiVO4 to capture the photogenerated holes. As a result, the PEC activities of Bi2MoO6/BiVO4 heterostructures were significantly improved due to the enhanced charge carriers separation efficiency. The special design of electron transport channel may provide a universal strategy to address the intrinsic drawbacks of type-I heterostructures.