摘要 : Depolymerization of cellulose, the most abundant biomass in nature, is a critical step for its catalytic conversion to fuels andchemicals. While cleavage of its glycosidic bond by acid hydrolysis is therate-determining step to dep... 展开 Depolymerization of cellulose, the most abundant biomass in nature, is a critical step for its catalytic conversion to fuels andchemicals. While cleavage of its glycosidic bond by acid hydrolysis is therate-determining step to depolymerize cellulose, disrupting its robustcrystalline structure is equally important. In this work, we examined thehydrolysis of cellulose of four different crystalline allomorphs, i.e., I, II,III, and IV, with respect to the conversion rate, change in the crystallinestructure, and the degree of crystallinity and polymerization during thereaction. Independent of their crystalline structure, the four cellulosesamples converted following thefirst-order reaction kinetics with noessential influence on the product selectivity. However, the rate constantswere largely different and decreased in the following sequence: celluloseII > III > I > IV. The high rate of cellulose II is caused by its higherreaction probability, as reflected by its preexponential factor, which is several orders of magnitude higher than that for the othercellulose samples, which overcompensated its high apparent activation energy. It is found that cellulose I and IV undergo surfacereactions at 478-508 K, whereas cellulose II and III swell at the reaction temperatures, which allows the hydrolysis reaction to occurin the whole swollen regions, leading to higher accessibility of the glycosidic bond to the H+catalyst and consequently higherconversion rates. Thesefindings provide the mechanistic basis for an alternative strategy to enhance the efficacy in depolymerization of cellulose via tuning of crystalline phases 收起