NiPt supported on zeolite Y and SBA-15 composites as efficient catalysts for the hydrodeoxygenation of anisole under mild conditions

The growing demand for fossil fuels and environmental problems are driving the search for green fuel alternatives. Bio-oil is a complex mixture of oxygenated compounds obtained from the pyrolysis of lignocellulosic biomass. Although its burning generates neutral CO₂ emissions, its use is limited by its high oxygen content, which leads to high viscosity, polarity, and low calorific value. In this sense, hydrodeoxygenation is a convenient treatment for transforming bio-oil into alkanes or aromatics, depending on the reaction conditions used. Among these products, cyclohexane is a valuable compound for industry and is found in the gasoline range. In this work, composite supports based on zeolite Y and SBA-15 were proposed for the preparation of NiPt catalysts evaluated in anisole HDO with the aim of producing cyclohexane. The physicochemical characteristics of the supports and catalysts were determined by different characterization techniques. The supports have a core–shell structure with hierarchical micro- and mesoporosity, which allows access to the zeolite Y micropore core. Adjustment of the zeolite Y content in the support allows regulation of the number of acidic sites in the final catalysts. In addition, a better dispersion of metals was observed in the catalysts supported on the composite materials than on the individual SBA-15 and zeolite Y. This had an impact on the reaction performance, where the NiPt/Y(X)-SBA-15 catalysts resulted in higher anisole conversions along with better selectivity to cyclohexane. The reaction mechanism has been proposed and elucidated using a kinetic approach. The developed kinetic model adequately describes the experimental results. The NiPt/Y(X)-S catalysts showed a stable activity in three repeated catalytic cycles, but a slight decrease in their selectivity to cyclohexane. The reasons of this behavior are discussed.