UiO-67 MOF-BASED CATALYST AS A POTENTIAL PHOTOCATALYST FOR CO2 CONVERSION TO METHANOL COMPLIMENTED BY RSM STUDIES

Abstract

Metal-organic frameworks (MOFs) have received significant attention in recent years due to their fascinating properties, such as high surface area, porosity, tuneable pore size, and structural flexibility. These characteristics make them promising candidates for various applications, particularly in the photocatalytic conversion of carbon dioxide (CO2). This research investigated the unitisation of Polyoxometalates (POMs) incorporated within MOFs as catalysts for converting CO2 to methanol. The POM@MOF catalyst was prepared by the solvothermal method, and its physicochemical properties were characterised through various techniques, including FTIR, UV-VIS, PXRD, TGA, FESEM, and BET. Response Surface Methodology (RSM) based on Central Composite Design (CCD) was employed to optimise the reaction conditions, focusing on catalyst loading and reaction time. Methanol concentration in the product was determined using HPLC. Notably, the encapsulation of Keggin SW12 into UiO-67(Zr) resulted in better physicochemical properties than pristine UiO-67. The optimal reaction conditions were determined to be a catalyst loading of 1.0 g/L and a reaction time of 3 hours. While the photocatalytic CO2 conversion was successfully conducted, methanol was not detected in both the proposed and modified experimental setups due to the low methanol concentration and the limitations of the detection instruments. This research establishes a lower-limit benchmark and contributes to the development of sustainable processes for CO2 photocatalytic conversion to methanol utilising the SW12@UiO-67 catalyst.