Description
Poster Session: 11-28-2017 - Tuesday - 08:00 PM - 10:00 PM
Juliana Torres1 Andre Nogueira1 Gelson Tiago da Silva2 1 Caue Ribeiro1

1, Brazilian Agricultural Research Corporation/Embrapa Instrumentation, São Carlos, , Brazil
2, Federal University of São Carlos, São Carlos, São Paulo, Brazil

The increase in energy consumption from the burning of fossil fuels coupled with the high emission of CO2 in the atmosphere has stimulated the search for solutions that reduce this emission of gases responsible for the greenhouse effect. An energetically favorable alternative is the photocatalytic reduction of CO2 since it aims to simultaneously use the emitted CO2 and the abundant solar energy to produce value-added chemical and fuel products [1]. Artificial photosynthesis uses solar power to convert raw materials like water and CO2 to useful chemicals, e.g., H2, CH4, CO, and hydrocarbons [2] Therefore, the success of this approach relies on two aspects; the eficiente utilization of solar power and the enhancement of the catalytic conversion of water and CO2 to fuels and chemical. Numerous heterostructures have been used for this proposal, among them MgO/TiO2 stands out due to the high adsorption capacity of CO2 molecules by MgO in the presence of H2O vapor, besides the easy desorption of the reaction products. In addition, TiO2 has the advantage of being low cost, chemically stable and non-toxic [3]. MgO on TiO2 photocatalysts can activated adsorbed CO2 molecules, which promotes the production of HCO3-, a possible intermediate for the production of hydrocarbon fuels or CO when the dissociative H atoms are available [3]. In this contexto, the objective of this study was to evalute the properties and the photocatalytic activity of heterostructures of MgO/TiO2 synthesized by co-precipitation method. In addition, the MgO semiconductor synthesized by the hydrothermal method was used to obtain higher superficial affinity for CO2 through its high adsorption capacity of this compound. The isolated semiconductors and the heterostructure were characterized by Xray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance UVVis spectroscopy (DRS), and nitrogen physical adsorption (BET method). The photocatalytic activity was evaluated using photoreduction CO2 in H2O vapor under ultravioleta irradiation using TiO2 and MgO/TiO2. The nanorods of TiO2 were successfully synthesized by the methodology used, being confirmed by the SEM. The band gap found for TiO2 through DRS confirms the stipulated in the literature (3,2 eV). The MgO/TiO2 heterostructure have been successfully synthesized by a facile co-precipitation method. The analysis of the gases after the photoreduction CO2 indicated the formation of CH4 mainly, being that after the synthesis of the heterostructure, the effect was more pronounced compared to the pure TiO2. This improvement can be attributed to the heterostructure between MgO and TiO2, which possibly facilitated charge transfer and the suppressed recombination of electron/hole pairs.

Meeting Program
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8:00 PM–10:00 PM Nov 28, 2017

Hynes, Level 1, Hall B