Construction of Z-scheme TiO2/Ag/ZIF-8 nanorod array film with boosting photocatalytic and photoelectrochemical properties

Improving photoanode charge separation ability is crucial to solar energy conversion efficiency. In this study, hydrothermal and in situ synthesis methods were used to fabricate novel Ag and ZIF-8 nanoparticles (NPs) to decorate plasmonic TiO2/Ag/ZIF-8 nanorod array films. The morphology, microstructure, chemical composition, optical properties, photocatalytic activity and photoelectrochemical performance of TiO2/Ag/ZIF-8 were systematically investigated. The results showed that TiO2/Ag/ZIF-8 exhibited robust photocatalytic and photoelectrochemical properties under visible light irradiation. The photocatalytic rate constant for tetracycline (0.01348 min−1) and photocurrent density (250.2 μA/cm2) of TiO2/Ag/ZIF-8 were 9.76 and 5.94 times that of TiO2, respectively. The optimal PC and PEC properties of TiO2/Ag/ZIF-8 were attributed to the synergistic effect of Ag and ZIF-8 NPs: i) the surface plasmon resonance effect of Ag NPs extends the absorption range of visible light; ii) the passivation effect of ZIF-8 suppresses photogenerated carrier recombination; iii) the N–Ti–O bonds between TiO2 and ZIF-8 elevate photogenerated carrier transfer.