Optimization and modeling of CO2 photoconversion using a response surface methodology with porphyrin-based metal organic framework

In the current study, porphyrin-based metal organic framework (M(metal)/PMOF) was used to photoreduction conversion of CO2 under UV/Visible light irradiation. The metal and linker selection in the M/PMOF synthesis influences its structure and properties. In this regards, M/PMOFs were prepared using three different metals of Zn, Al, and Co. The prepared photocatalysts were characterized by powder X-ray diffraction (XRD), N-2 adsorption BET surface area, scanning electron microscopy (SEM), Energy dispersive X-ray spectrometer (EDX), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. Also, the photoluminescent properties and photoreactor tests, for these three photocatalysts were investigated. The obtained results demonstrated that Al/PMOF has high CO2 photoreduction conversion, 4.3%. The operating conditions were optimized to find the best conditions which are lead to high CO2 photoreduction conversion over Al/PMOF. For this purpose, the experiments were conducted based on central composite design (CCD) and analyzed using response surface methodology (RSM). The ANOVA analysis revealed that the maximum photoreduction conversion of CO2, as 10.63%, can be obtained at the optimum conditions (catalyst amount of 297.24 mg, total feed pressure of 1.4 atm and methanol as sacrificial agent). Finally, a verification experiment was performed and results confirmed the validity and adequacy of the predicted model for simulating the CO2 photocatalytic conversion.