Design of core-shelled g-C3N4@ZIF-8 photocatalyst with enhanced tetracycline adsorption for boosting photocatalytic degradation

Confining active species and intermediates in a limited spatial is critical to driving pollutant transformation involving successive reactions for boosting degradation. Herein, core?shell g-C3N4@ZIF-8 were prepared by exfoliating-wrapping of g-C3N4 via ZIF-8 in-situ growth. XRD, SEM, TEM, and EDX mapping demonstrate the inclusion of curled g-C3N4 sheets in ZIF-8. UV?vis, PL, FTIR, and XPS confirm the coordination of TC with Zn of ZIF-8. Steady-transient PL, EIS and transient photocurrent response indicate that the combination of two materials favors the carriers? separation and transfer. Further band analysis suggests that interfacial band bending of g-C3N4 promotes the separation of electron-hole and electron diffusion toward ZIF-8. As result, the optimized gC3N4@ZIF-8 exhibits a superior TC degradation rate constant (k = 0.068 min-1), 4.8 times higher than that of gC3N4 (k = 0.014 min-1), and enhanced TC removal rate of 87.6% higher than g-C3N4 (58.6%). Also, the optimized material shows superior degradation rate and removal efficacy in RhB (99.3%) and Cr (VI) (96.6%) in surface water. The investigations on active species and degradation routes (EPR, LC-MS) reveal that synergetic effects of ZIF-8 confined g-C3N4 facilitate the formation of oxygen radicals (?O2- ) and their transformation toward singlet oxygen (1O2) for boosting TC degradation.

Automated summary

The study found that gC3N4@ZIF-8 exhibits superior performance in enhancing TC degradation, with significantly higher degradation rate constant and removal rate compared to gC3N4 alone. Additionally, the optimized material also shows excellent degradation and removal efficacy in RhB and Cr (VI), accelerating pollutant degradation by promoting the formation and transformation of oxygen radicals.