Insights on Z-scheme interfacial charge transfer of TiO2-NRAs/BiOI-NFs/Au-NPs nanoheterostructures and unveiling enhanced photoelectrochemical performances

We synthesized TiO2-NRAs/BiOI-NFs/Au-NPs ternary Z-scheme nanoheterostructure using an accessible preparation method. The ternary nanoheterostructure exhibited enhanced photoelectrochemical (PEC) performance compared to other binary nanoheterostructure. The improved performance was attributed to the synergistic effect between enhanced charge separation and improved injection efficiency. An interfacial charge migration mechanism involving plasmon-induced hot electron injection and transition with oxygen vacancies defects was proposed. The triple nanohybrids showed a higher photodegradation rate for methyl orange (MO). Based on the scheme, the TiO2-NRAs/BiOI-NFs/Au-NPs ternary nanohybrids exhibited a photodegradation rate of 96.6% toward degradation of MO irradiated by UV-visible light, 1.47 and 1.19 fold that of BiOI-NFs/Au-NPs and TiO2-NRAs/BiOI-NFs, respectively. Furthermore, the TiO2-NRAs/BiOI-NFs/Au-NPs ternary nanoheterojunction exhibits the best photodegradation performance under near-infrared light irradiation, with a photodegradation rate 4.3 times and 1.2 times that of the binary TiO2-NRAs/BiOI-NFs and BiOI-NFs/Au-NPs nanoheterojunction composites, respectively. These findings provide insights into interfacial charge transfer in TiO2-NRAs/BiOI-NFs/Au-NPs nanoheterostructures and demonstrate their enhanced PEC performances, inspiring the design of high-efficiency and non-toxic Z-scheme heterostructures for various applications.