Navegando por Autor "Pinto, Alexandre Henrique"
Agora exibindo 1 - 2 de 2
Resultados por página
Opções de Ordenação
Item Doped tin dioxide (d-SnO2) and its nanostructures : review of the theoretical aspects, photocatalytic and biomedical applications.(2022) Pinto, Alexandre Henrique; Nogueira, André Esteves; Dalmaschio, Cleocir José; Frigini, Iago Nunes; Almeida, Jessica Cristina de; Ferrer, Mateus Meneghetti; Berengue, Olivia Maria; Gonçalves, Rosana Alves; Mendonça, Vagner Romito deNanomaterials based on metal oxides are extensively studied for several applications due to their versatility. Improvements in their performances can be obtained due to specific structural modifications. One possible modification is by doping the crystal structure, which can affect the materials structure and properties, especially in nanosized particles. Electronic features are among the properties that can be modified through the doping process, consequently morphological and optical parameters can also be controlled by this process. In this sense, this review presents some modifica- tions to tin dioxide (SnO2 ), one the most studied materials, mainly through the doping process and their impact on several properties. The article starts by describing the SnO2 structural features and the computational models used to explain the role of the doping process on these features. Based on those models, some applications of doped SnO2 , such as photocatalytic degradation of pollutants, CO2 reduction, and desulfurization of fossil fuels are presented and discussed. Additionally, the review describes many biological applications related to antimicrobial activity for doped SnO2 and its nanostructures. Although most of the examples presented in this article are based on the doped SnO2 , it also presents examples related to SnO2 composites with other nanomaterials forming hetero- junctions. The metal oxides SnO2 , doped-SnO2 and their nanostructures are promising materials, with results reported in many fields presented in this review, such as theoretical and computational chemistry, environmental remediation, nanoparticle morphology control, fossil fuels improvement, and biomedical applications. Although widely explored, there are still fields for innovation and advances with tin dioxide nanostructures, for example, in transparent conducting oxides, in forensics as materials for latent fingerprints visualization, and sensors in medicine for detection of exhaled volatile organic compounds. Therefore, this article aims to be a reference regarding correlating the doping processes and the properties presented by the SnO2 nanostructures.Item The facile microwave-assisted coprecipitation route to obtain polyoxoniobate (Na7 (H3O) Nb6O19·14H2O) nanorods modified with copper for CO2 photoreduction.(2023) Sousa, Joelma Raimunda de Carvalho; Torres, Juliana Arriel; Ribeiro, Lucas da Silva; G. Filho, José B.; Santos, Fabiana Lesse dos; Malgioglio, Nicholas; Gorup, Luiz Fernando; Pinto, Alexandre Henrique; Nogueira, André EstevesThe CO2 reduction by solar means has been discussed as an alternative to emission abatement, a fundamental topic for sustainable, carbon-free production in the future. However, the choice of efficient systems, starting with the catalysts, is still a critical issue, especially due to the poor activity of available options. Polyoxometalates have been extensively studied as promising photocatalysts due to their semiconducting properties. Nevertheless, the synthetic conditions of polyoxoniobate are stringent due to the low reaction activity of Nb species, the lack of soluble precursors, and the narrow pH range. Unlike the literature, in the present study, we report a simple polyoxoniobate synthesis method. This synthesis method has some remarkable features, such as low processing time and temperature and good activity and selectivity in the CO2 photoreduction process. The results revealed an outstanding efficiency for the CO2 reduction reaction with a high selectivity of CO2 to CO conversion (92.5%). Furthermore, C2 compounds (e.g., acetate) were produced in the liquid phase of the reaction system. Our findings are significant for indicating the potential of polyoxoniobate for CO2 photoreduction, which opens a way to control competitive reactions with synthesis, leading to higher selectivity.