Development of magnesium oxide with zinc and titanium heterostructure for application in artificial photosynthesis processes

Abstract

Energy production from burning of fossil fuels significantly contributes to global warming, thus highlighting the need for economically viable and energetically favorable alternatives for energy production through clean and sustainable routes. Artificial photosynthetic routes can recover the energy potential of these emissions by CO2 reduction (activated by sunlight)to compounds as CO and CH4, which can be reused in further processes. To this end,semiconductor oxides are proposed in the literature as catalysts in this process, considering that during the irradiation a pair electron/hole able to promote redox reactions is formed. However, several challenges are imminent, as the low surface affinity for CO2 of the typical semiconductor and typical low reduction potential, leading to other reduction reactions. Thus this project proposes the development of a heterostructure synthesis route MgO/TiO2 and MgO/ZnO in which the high affinity of CO2 to the MgO surface may promote the selectivity for this reaction, and simultaneously, the transfer of charge carriers in heterostructures (isolating the holes generated in TiO2 or ZnO) increasing the effectiveness of the process. Firstly, the heterostructures are to be obtained by inorganic salts co-precipitation routes on the surface of TiO2 particles or ZnO previously prepared, followed by calcination, where the various synthesis parameters will be investigated (proportion of oxides, pH of precipitation, temperature calcination, etc.). To assess and understand the influence of these materials in the photocatalytic process, studies of thestructure and morphology of the same will be conducted using XRD, FTIR and Ramanspectroscopy. The morphological aspects will be analyzed by high resolution microscopy (FESEMand HRTEM). The surface properties are to be analyzed by XPS. On the other hand, the opticalproperties will be investigated by DRS/UV-Vis and PL. These materials are to be used in thephotoreduction of CO2 in the liquid (batch) and gas phases to obtain compounds such as CO, CH3,CH4, and others (using ultraviolet and visible radiation). Furthermore, the influence of theoperating parameters of reaction such as temperature, radiation type, the initial mass of the photocatalyst and the gas flow will be investigated. (AU)