Síntese via reação de combustão de catalisadores NiFe2O4 utilizados nas reações de deslocamento de vapor d’água (WGRS) e oxidação seletiva (PROX).

Abstract

The hydrogen is an alternative source for electric power generation using systems of combustible cells. The hydrogen can be produced starting from different reactions as: water gas shift reaction and selective oxidation. This way, the goal of this research work involves the development (prepare, to characterize and to evaluate) of the NiFe2O4 catalyst by combustion reaction method, using two fuels: urea and glicine aiming your application in the water gas shift reaction (WGSR) and selective oxidation (PROX), promoting the purification of the hydrogen by the elimination of the carbon monoxide. The powders were obtained by combustion reaction according to the chemistry of propellants using as container a silica crucible vitreous; the maxim flame temperature and average flame time were verified during the synthesis. The resulting powders were characterized by X-ray diffraction, spectroscopy of infrared, (FTIR), superficial area and isothermal of adsorption/dessorption by means adsorption of nitrogen the method (BET), pore distribution (BJH), scanning electronic microscopy and catalytic measures. The results show that, the catalysts present crystalline majority phase of inverse spinel and metallic Ni traces for the catalyst NFG. Both catalysts introduced of inverse spinel characteristic bands. The NFG catalyst presents smaller superficial area, and consequently, the larger size ferrites particle and characteristic soft agglomerates. The catalyst NFG introduced kind III isothermal, however the NFU catalyst presents kind II isothermal. But both catalyst present H3 hysteresis. The NFU catalyst introduced better catalytic performance for WGSR and better reagents conversions to the lower temperature for PROX.