Zeólita com estrutura hierárquica de poros e impregnada com níquel aplicada como catalisador heterogêneo para a conversão de CO2

Abstract

Carbon monoxide and methane are some of the possible products of CO2 hydrogenation. The latter is a greenhouse gas with rising atmospheric concentration, and its conversion in value added products is interesting. Catalysts supported in hierarchical zeolites are promising materials due to their hydrothermal stability and facilitated diffusion. In this work, USY zeolite was dealuminated using 1 mol L-1 solutions of two different acids: oxalic and citric. Oxalic acid treatment removed almost all Al from the material, staying below the X-ray fluorescence analysis detection limit. This resulted in an amorphous material and in reduced textural parameters. Citric acid treatment increased Si/Al ratio by almost twenty times, preserved some USY zeolite crystallinity and increased all the textural parameters. The materials were impregnated with nickel 5 and 10% weight and were used as catalysts. No conversion of CO2 was observed when only NiO particles were used as catalyst. On the other hand, the zeolite with supported nickel produced CO and CH4, showing the value of the zeolitic support. Modified materials are promising catalysts for CO2 conversion and more analysis are necessary to explore their potencial.