Dense Ru single-atoms integrated with sulfoacids for cellulose valorization to isosorbide

Metal-acid bifunctional catalysts are the unity of two opposites (metal-acid repelling) for cellulosic biomass valorization to isosorbide. It is challenging to improve the selectivity of metal hydrogenation catalysts and their synergism with acids for catalytic hydrolysis and dehydration to achieve substantial isosorbide. Herein, dense Ru single-atoms (10.1 wt% of Ru SAs) are anchored on sulfoacid-functionalized hollow mesoporous carbon shells, designed by assembling silica and 8-hydroxyquinoline-modified chitosan (HQ-CTS) through in situ Stoeurober templating strategy before pyrolysis and acid treatment. Based on X-ray absorption fine structure and computational modeling results, the structure of Ru SAs is determined as RuN4, which is more selective for a transitional glucose hydrogenation to sorbitol than Ru001 of Ru clusters. A lower-energy barrier of 1.21 (0.72) eV is delivered over RuN4 (Ru001) for glucose hydrogenation (isomerization). These Ru SAs are integrated with sulfoacids (SO3H) but resistent against acids, rendering enhanced isosorbide yield in water as compared to Ru clusters, via a one-pot cascade reaction under harsh conditions (220 degrees C, 6 MPa H2). The elaborately fabricated dense Ru SAs and sul-foacids, achieved by varying the addition time of HQ-CTS during the in situ Stoeurober templating process, improve the synergism of glucose hydrogenation with cellulose hydrolysis and sorbitol dehydration. This study provides a new idea for rational design of high-performance metal-acid bifunctional catalysts toward one-pot conversion of cellulose to isosorbide.(c) 2023 Elsevier Ltd. All rights reserved.

Automated summary

In this study, a metal-acid bifunctional catalyst, consisting of dense Ru single atoms supported on sulfoacid-functionalized mesoporous carbon, was fabricated for the selective conversion of glucose to isosorbide. The catalyst showed improved selectivity and activity compared to traditional Ru clusters, and the synergistic effect between the metal and acid sites facilitated the cascade reaction under harsh conditions. This research provides a new approach for the rational design of high-performance catalysts for the one-pot conversion of cellulose to isosorbide.