A Mesoporous Carbon‐Supported Pt Nanocatalyst for the Conversion of Lignocellulose to Sugar Alcohols

Abstract

The conversion of lignocellulose is a crucial topic in the renewable and sustainable chemical industry. However, cellulose from lignocellulose is not soluble in polar solvents, and is, therefore, difficult to convert into value-added chemicals. A strategy to overcome this drawback is the use of mesoporous carbon, which enhances the affinity between the cellulose and the catalyst through its abundant functional groups and large uniform pores. Herein, we report on the preparation of a Pt catalyst supported on a type of 3D mesoporous carbon inspired by Echinometra mathae (Pt/CNE) to enhance the interaction between the catalyst and a nonsoluble reactant. In the hydrolytic hydrogenation of cellulose, the abundant oxygen groups of CNE facilitated the access of cellulose to the surface of the catalyst, and the open pore structure permits cello-oligomers to effectively diffuse to the active sites inside the pore. The highly dispersed Pt performed dual roles: hydrolysis by in situ generating protons from H2 or water as well as effective hydrogenation. The use of the Pt/CNE catalyst resulted in an approximately 80 % yield of hexitol, the best performance reported to date. In direct conversion of hardwood powder, the Pt/CNE shows good performance in the production of sugar alcohols (23 % yield). We expect that the open-structured 3D carbon will be widely applied to the conversion of various lignocellulosic materials.

Dendritic Silica Particles with Center-Radial Pore Channels: Promising Platforms for Catalysis and Biomedical Applications

“…The Pt‐loaded carbon catalyst exhibited a high 80% yield of hexitol from cellulose, the best performance reported thus far. This probably resulted from the open pore structure, which permitted cello‐oligomers to effectively diffuse to the active sites inside the pore . Stein's group fabricated hollow carbon spheres with mesoporous shells by nanocasting carbon into dendritic MSNs via phenol‐paraformaldehyde gas‐phase polymerization and subsequently removing the silica structure by hydrofluoric acid etching …”

Mechanism and Kinetic Analysis of the Hydrogenolysis of Cellulose to Polyols

“…Carbons are hydrothermally stable under the reaction conditions typically at temperatures of 423-573 K. Moreover, the surface of carbon materials can be furnished with plenty of OH and carboxyl groups. Such weak acidic sites have been found to contribute to the activation of the glycosidic bonds in cellulose and consequently promote the hydrolysis of cellulose [27,35,[47][48][49][50][51]. Conversely, strong acid sites on carbon materials are unequivocally effective for cellulose hydrolysis [52][53][54].…”

Enhanced Sugar Alcohol Production from Cellulose by Pretreatment with Mixed Ball-Milling and Solid Acids

“…This yield was the highest obtained in this study. Moreover, the total ballmilling and reaction time (4.5 h) was remarkably shortened by this optimized process compared with previously published methods where the overall time was greater than 24 h (Park et al 2013). This result demonstrated that mixed ball-milling of cellulose and solid acid catalyst is highly effective in promoting cellulose conversion.…”