Graphitic Carbon Nitride Composites with Gold and ZIF-67 Nanoparticles as Visible-Light-Promoted Catalysts for CO₂ Conversion and Bisphenol A Degradation

In this research work, the ZIF-67-coupled plasmonic-gold-incorporated porous g-C3N4 (ZIF/Au-PCN) nanocomposites have been successfully synthesized and utilized for the conversion of CO2 into useful products and Bisphenol A (BPA) decontamination. Compared to pristine PCN, the photocatalytic activities of the most active 3ZIF/1.5Au-PCN nanocomposite are enhanced by 8.0-fold for the conversion of CO2 and by 2.5-fold for BPA degradation. On the basis of our experimental results, it is verified that the porous nature increases the surface area of g-C3N4. Remarkably, the incorporation of Au exceptionally adjusts the band gap of g-C3N4 from 2.7 to 2.48 eV via the surface plasmon resonance (SPR) effect, while the coupling of a metal–organic framework (MOF; ZIF-67) not only enhances the surface area but also prominently enhances the charge separation of g-C3N4 via a photoelectron modulation mechanism. In addition, transmission electron microscopy, scanning electron microscopy, photocurrent action spectroscopy, electrochemical impedance spectroscopy, time-resolved photoluminescence, fluorescence spectroscopy linked with •OH amount, Fourier transform infrared, Brunauer–Emmett–Teller, etc., confirmed that the insertion of a noble-metal Au atom and the fabrication of a MOF offered a suitable energy platform and improved the photocatalytic activities for BPA decontamination and CO2 conversion into valuable products. Moreover, on the basis of thermogravimetric analysis and stability tests, it is proven that the as-synthesized samples are highly stable and no morphological and physiochemical changes are observed before and after various analyses and photocatalytic reactions. Hence, our present research work will manifestly open an innovative gateway and feasible strategy to prepare MOF-supported and plasmonic-assisted g-C3N4-based porous and highly efficient photocatalysts for CO2 conversion and environmental protection.