Preparation and characterization of TiO2 nanostructured electrodes modified with metal organic frameworks (MOFs) for application in the preconcentration and reduction of CO2

Abstract

Carbon dioxide (CO2) is one of the main gases responsible for the greenhouse effect and in high concentrations in the atmosphere has caused several climate changes that affecting directly the survival of some ecosystems and the quality of life of humanity. In an attempt to minimize this problem, different methodologies are being proposed to reduce the concentration of CO2 in the atmosphere. Among the different methodologies, the photoeletrocatalytic processes are widely used, since they can reduce the CO2 molecule to high value added compounds such as CO, CH4, CH3OH, HCHO and HCOOH, among others. However, this methodology presents some limitations such as: low solubility of CO2 in aqueous medium, low selectivity in the conversion of CO2, low efficiency of the semiconductor materials and low adsorption of CO2 on the surface of the semiconductor material, which becomes the process efficiency relatively low. One of the alternatives to improve the efficiency of these processes would be the superficial modification of the semiconductor material using the metal organic frameworks known as MOFs. This new class of compounds presents unique characteristics (high surface area, low density, reasonable thermal stability and the possibility of surface modification due to the organic portion in the material) that allow its application in different areas, such as storage and gas separators, drug carriers and heterogeneous catalysts, among others. Thus, it is intended to obtain TiO2 nanostructured semiconductor materials and modified with Au@ZIF-8, Ru-BTC and UiO-66(Zr)-NH2 MOFs that are capable of minimizing the limitations of the photoelectrocatalytic processes with good selectivity, capture, storage and catalysis of CO2 molecules, thus raising the conversion efficiency of CO2 to compounds with high added value.