Direct Z-scheme heterostructure of p-CuAlO/n-BiWO composite nanofibers for efficient overall water splitting and photodegradation.

Constructing heterostructures can facilitate photoinduced charge separation, leading to enhanced photocatalytic performance. However, spatial separation of charge carriers in traditional type II heterojunctions is at the expense of their redox ability. In this paper, well-designed direct Z-scheme systems (ZSS) of p-CuAlO/n-BiWO composite nanofibers with uniform non-woven web nanostructure was built by electrospinning technique and solvothermal reactions. The formation mechanism of the ZSS and the charge migration pathway is investigated in detail. Results show that as-prepared composite nanofibers exhibit desirable photocatalytic performance for overall water splitting due to its stronger redox power and efficient charge separation. Meantime, it shows great activity for photodegradation of various organic pollutant models (RhB, MO, 4-NP), which is 1 order of magnitude higher than the single-component CuAlO and BiWO. Furthermore, the composite nanofibers exhibit well separable properties by natural sedimentation because of its ultra-long and non-woven web nanostructure. The paper explores CuAlO and its Z-scheme heterostructures in water splitting for the first time, which may highlight its new applications.