Catalytic Pyrolysis of Moso Bamboo Over Acid‐treated Red Mud Catalyst for Bio‐Oil Production

Abstract Red mud (RM), one kind of waste from the alumina industry, was used to prepare 600‐RM catalyst and a series of xHCl‐RM catalysts. The catalytic pyrolysis of moso bamboo was conducted to evaluate the performance of the prepared catalysts. The 600‐RM catalyst showed a slight increase in the content of Fe, Al, Ca and Si, and a modest enlargement in pore volume and diameter. The xHCl‐RM catalysts exhibited well‐structured hierarchical porosity and enhanced specific surface area. After acid treatment, the contents of Fe, Al, and Si increased noticeably, with almost complete removal of Na and Ca. Thermal stability of the 600‐RM and xHCl‐RM catalysts was significantly improved compared to P‐RM. The results showed that the catalytic pyrolysis over 600‐RM enhanced high selectivity for phenols (59.81%, biomass/catalyst = 1/1 w/w) and alcohols (16.35%, biomass/catalyst = 1/1 w/w), facilitated by CaO promoting bond cleavage and free radical reactions. In addition, xHCl‐RM demonstrated enhanced activity for furans (23.11%) and carbonyl compounds (28.43%), with 4HCl‐RM performing the best. It could be attributed to the high cracking ability of Fe 2 O 3 and Al 2 O 3 on cellulose and hemicellulose. The biomass‐to‐catalyst mass ratio significantly affected the yield of small molecular products, showing a nonlinear trend.