Insight into impact of ZrO₂ nanoparticles on photocatalytic degradation performance of g-C₃N₄ for tetracycline

Background: Transition metal oxides have been proved effective for improving photocatalytic performance of graphitic carbon nitride by constructing different heterojunctions. Although much progress has been made in this field, the effect of transition metal oxides on photocatalytic process is still not very clear. Aims: Herein, we fabricated g-C3N4/ZrO2 based photocatalyst and investigated its morphology, elemental state and photophysical process. Materials & Methods: g-C3N4/ZrO2 was performed through physical mixing methods. In order to delve into the effect of ZrO2 doping on g-C3N4, detailed characterization was done by SEM, TEM, BET, PL, XRD, XPS, UV-vis DRS, FTIR, TRPL and EPR. Results & Discussion: Smaller nanoscale morphology and larger specific surface area for g-C3N4/ZrO2 photocatalyst are confirmed by SEM and BET results. Photoelectrochemical experiments indicate that charge transfer process is significantly improved and bigger photogenerated current is achieved. Electron paramagnetic resonance results also show that center dot O-2 signal is enhanced obviously with ZrO2 nanoparticles under light condition. Time-resolved photoluminescence spectra further explain that ZrO2 is favorable for charge transfer with shortened exciton lifetime while unfavorable for charge transport with shortened recombination lifetime. Conclusion: Finally, the compromise photodegradation performance of g-C3N4/ZrO2 for tetracycline is enhanced by 70% compared with pure g-C3N4.