To accomplish a technical feasibility and high selectivity controllable hydrolysis pathway, transition metal salt catalysts have been used as a potential hydrolyzing agent in the cellulose depolymerization process. Today, metal salts have been discovered to have the following notable advantages over inorganic acids or organic solvents in cellulose hydrolysis: (i) can disrupt the hydrogen bonds more efficiently and induce the degradation of cellulose; (ii) less corrosive and more environment-friendly; and (iii) better contact between molten state metal salts and solid cellulose . According to literature studies, chromium-based metal salt catalysts have been found to be highly effective in direct conversion of cellulosic resources into different chemicals and liquid fuels such as glucose, hydroxymethylfurfural (HMF), xylose and levulinic acid. Binder and Raines  reported that CrCl2-catalyzed hydrolysis of cellulose could produce a high yield of HMF (ca. 54%) in the N,N-dimethyl acetamide solvent containing [EMIM]Cl and lithium chloride (LiCl) additives at 140 °C for 2 h. Su et al.  investigated the effect of CrCl2 in [EMIM]Cl ionic liquid on the cellulose hydrolysis, and the results revealed that 58% of HMF was successfully achieved under the reaction conditions of 120 °C for 8 h. In recent years, a study performed by Peng et al.  found that CrCl3 catalyst was exceptionally effective in the conversion of cellulose to levulinic acid with a maximum yield of 67 mol % at 200 °C for 180 min. During the catalytic hydrolysis, the multivalent metal ions act as a Lewis acid that possess a high ability for hydrolyzing the cellulose matrix by disrupting the bonding system to produce fermentable sugar molecules, and it had better efficiency compared to diluted acid alone . Therefore, it is believed that the intermediate solid crystalline nanocellulose could be produced instead of water-soluble monomer molecules under controlled low severity hydrolysis settings.