Raspberry-like hydroxyl-rich carbon layer coated solid catalyst to promote the hydrolysis of cellulose to sugar through local strong absorption

Raspberry-like carbon layer coated silica nanoparticles (MSN-x-NH2 @C) with controllable hydroxyl-rich rough surface is designed and synthesized by use of alkaline etching strategy and hydrothermal carbonization (HTC) method, which is utilized as catalyst to provide particular interaction with cellulose between the solid-solid interfaces. Through the control of surface roughness of the raspberry-like catalyst, it induces the formation of local area with strong absorption on the surface and thus enhance the capability to disrupt the aggregated structure of cellulose. Accordingly, in low acidic aqueous system with MSN-x-NH2 @C, the cellulose conversion rate is up to 91.99% with the total reducing sugar yield at 81.46% and glucose yield of ∼70% after the second hydrolysis in aqueous system. Furthermore, the obtained MSN-x-NH2 @C exhibits good thermal stability and reusability. This research provides a new perspective for the design and preparation of nano-sized solid catalyst with controlled surface topological structure to enable the surface adsorption capability towards cellulose more efficiently in aqueous system.