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Previous issue date: 2017-10-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O objetivo desta tese foi desenvolver novos materiais catal?ticos ? base de molibd?nio (Mo) por meio da s?ntese de suportes mesoporosos de s?lica e de carv?o e avaliar seu desempenho na hidrodeoxigena??o de mol?culas plataforma em fase gasosa. O desempenho do catalisador, do suporte e do comportamento suporte/catalisador em diferentes condi??es reacionais foram estudadas. Os carbonos mesoporosos foram obtidos utilizando os materiais de s?lica (SBA-15 e KIT-6) como molde. A incorpora??o do ?xido de molibd?nio (MoO3) aos diferentes suportes foi realizada pelo m?todo de impregna??o ao ponto ?mido a fim de obter um teor de 4 e 2 ?tomos de Mo/nm?. As t?cnicas de caracteriza??o empregadas foram a difratometria de raios X (DRX), fisissor??o de N2 a 77 K, microscopia eletr?nica de varredura (MEV) e microscopia eletr?nica de transmiss?o (MET) que permitiram confirmar a s?ntese dos materiais de s?lica e carbono e a efetiva incorpora??o do ?xido de molibd?nio. A t?cnica de capacidade de estocagem de oxig?nio (OSC) permitiu investigar o efeito dos pr?-tratamentos t?rmicos sobre o MoO3 e, partir disso compreender a influ?ncia desses pr?-tratamentos no desemprenho catal?tico desses materiais. Al?m do MoO3 suportado, foram feitos testes catal?ticos com Mo2C carburado in situ e ex situ. Os materiais foram avaliados nas rea??es de hidrodeoxigena??o do fenol com temperatura de rea??o de 300 ?C e diferentes temperaturas de pr?-tratamento para o MoO3 suportado. Todos os catalisadores apresentaram seletividades a produtos desoxigenados superiores a 97 %. Os ?xidos suportados nas r?plicas de carv?es mesoporosos apresentaram convers?es superiores que o ?xido suportado nos materiais de s?lica. O aumento da temperatura de pr?-tratamento influenciou positivamente na convers?o a produtos desoxigenados para o ?xido suportado nos templates de s?lica e em suas r?plicas. As rea??es utilizando Mo2C apresentaram valores de convers?o superiores (27 %) aos valores observados com MoO3 (~1,3 ? 18,5 %), por?m n?o foi observado uma influ?ncia significativa dos suportes. / The aim of this thesis was to develop new catalytic materials through the synthesis of mesoporous silica and carbon supports for Mo impregnation to study its catalytic performance in hydrodeoxygenation of gas-phase platform molecules, where it was tried to determine the influence of the catalyst, support and support/catalyst behavior under different reaction conditions. Mesoporous carbons were obtained using the silica materials as a template. The impregnation of molybdenum oxide (MoO3) was carried out by the incipient wetness impregnation to obtain an amount of 4 and 2 Mo atoms/nm? in the silica and carbon supports. Characterization was performed using several techniques such as X-Ray Diffraction (XRD), N2 physisorption, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), by these techniques was possible to confirm the synthesis of the silica and carbon materials and the subsequent impregnation of the molybdenum oxide. The oxygen storage capacity (OSC) technique allowed investigating the effect of thermal pre-treatments on MoO3 and, from this, to understand the influence of these pre-treatments on the catalytic performance of these materials. In addition to the supported MoO3, catalytic tests were performed with in situ and ex situ carburized Mo2C. The materials were evaluated in the hydrodeoxygenation reactions of the phenol with reaction temperature of 300 ? C and different pretreatment temperatures for the MoO3 supported. All catalysts presented selectivities to deoxygenated products higher than 97%. The oxides supported on the mesoporous carbon replicates showed higher conversions than the oxide supported on the silica materials. The increase in pretreatment temperature positively influenced the conversion to deoxygenated products for the oxide supported on the silica templates and their replicates. Reactions using Mo2C showed higher conversion values (27%) to the values observed with MoO3 (~ 1.3 - 18.5%), but no significant influence of the media was observed.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/24931 |
| Date | 06 October 2017 |
| Creators | Rigoti, Eduardo |
| Contributors | 50942611004, Melo, Dulce Maria de Ara?jo, 06117988320, Braga, Tiago Pinheiro, 00880643366, Santos, Anne Gabriella Dias, 05004206457, Rodella, Cristiane Barbieri, 18099972830, Silva, Victor Luis dos Santos Teixeira da, 78917050700, Pergher, Sibele Berenice Castella |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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