The influence of cobalt in bimetallic Ni-Co catalyst supported on H-Beta for phenol hydrodeoxygenation
Hydrodeoxygenation (HDO) is considered as a promising technology for upgrading of bio-oil, obtained from fast pyrolysis of biomass, for renewable liquid fuel production. However, the development of suitable catalysts for this process is challenging up to now due to high coke formation and deactivation. In this paper, we describe a new bimetallic catalyst using non-sulfided, non-noble metals for HDO of phenol as model compound for bio-oil. The results show that the combination of nickel and cobalt supported on zeolite Beta (H-Beta) to form a bimetallic catalyst not only increased activity but also changed the product distribution toward saturated hydrocarbons as compared to monometallic Ni/Beta and Co/Beta catalysts. Moreover, Ni-Co bimetallic catalyst effectively avoided coke formation. The formation of Ni-Co alloy in Ni-Co/Beta catalysts led to reduced particle sizes and hence increased the dispersion of active sites on Ni-Co/Beta and finally improved catalytic performance. Notably, 96% selectivity to hydrocarbon at 97% phenol conversion were achieved on 10%Ni10%Co/Beta catalyst at 250°C within 5 h reaction time.
Due to the shortage of fossil fuel and environmental concern, the search for alternative and renewable energy resources has attracted attention all over the world. Of the interesting resources (solar, wind, biomass, geothermal and so on), biomass is regarded as an abundant sustainable source for production of carbon based fuel. Thus, the conversion of biomass to renewable liquid fuels has received considerable interest for partly replacing conventional fuels. There are several pathways to convert biomass to liquid fuels in which biomass fast pyrolysis and subsequent upgrading of resulting bio-oil is a promising one. The conversion of biomass to bio-oil via fast pyrolysis increases volumetric and energy density and therefore reduces the transportation costs (1). However, the direct use of bio-oil for combustion engine/turbine has some implications because of different properties of bio-oil compared with conventional fossil fuels. More than 200 compounds in bio-oils are known, having various types of functional groups with specific chemistry. Furthermore, water also accounts for 15-30 wt% (1). Therefore, upgrading of bio-oil is necessary to ma ...