Facile preparation of mesoporous alumina-silica catalysts derived from rice husk ash for fast catalytic pyrolysis of biomass

The utilization of waste biomass for catalytic pyrolysis presents an economical strategy for high-quality biofuel production. This study investigates the catalytic pyrolysis of various biomass feedstocks, including rice husk, sugarcane bagasse, and coconut coir, over mesoporous alumina-silica (MAS) catalyst. A series of MAS catalysts was synthesized through a one-pot process by co-assembling cetyltrimethylammonium bromide with a silica precursor derived from rice husk ash, with Al-to-Si ratios ranging from 4 to 16. The incorporation of aluminum functional groups into the rice husk ash-derived silica matrix promoted the formation of co-existing small pores with a narrow pore size distribution, enhancing hydrogen adsorption and Br & oslash;nsted acidity. Additionally, higher aluminum content resulted in a reduction in surface area and pore size, while acidity increased. The MAS4 catalyst demonstrated remarkable oxygen removal efficiency and high aromatic yield across various biomass feedstocks (exceeding 73 % for sugarcane bagasse) in the liquid product at a reaction temperature of 500 degrees C and atmospheric pressure. The stability of the MAS4 catalyst, retained over three catalytic cycles without any treatment, underscores its potential in developing catalysts optimized for selective catalytic pyrolysis of specific biomass types, especially for producing of aromatic hydrocarbon compounds, valuable as monomers and fuel additives.