Abstract
Background: Increasing demands in resource consumption cannot be sustained by a reliance on fossil fuels because of limited supply and catastrophic consequences to climate change. Cellulose is being deemed as the most valuable renewable resources and cellulosic biofuels have been regarded as the most promising candidates to substitute current fossil fuels. This review aims to depict the state-of-the-art development of solid acidic nanostructured catalysts employed in the selective conversion of cellulose into glucose, fructose, 5-hydroxymethylfurfural (HMF) and 5- ethoxymethylfurfural (EMF) via hydrolysis, isomerization, dehydration and etherification.
Methods: We try to describe multiple catalytic processes in the catalytic transformation of cellulose into glucose, fructose, HMF and EMF promoted by nanoscale catalysts. Emphasis is also paid to discuss plausible reaction pathways mediated by the nanostructured catalysts with different functionalities. Results: With regards to the efficiently catalytic transformations of cellulose, nano-catalysts are showing great potential in greener processing, higher yield and selectivity’s and more favorable economics. 5 tables are presented in details in this review in order to describe the different performance of solid acidic nanostructured catalysts regarding the reaction pathways, including hydrolysis of cellulose into glucose, isomerization of glucose into fructose, dehydration of fructose into HMF, and etherification of HMF into EMF. Likewise, 7 schemes are also described to demonstrate the reaction mechanism of the transformation reactions and the structure-property of the catalysts. This review depicted the state-of-the-art development of solid acidic nanostructured catalysts employed in the selective conversion of cellulose chemicals and biofuels regarding the design and optimization of these materials, and green catalysis. Conclusion: The catalytic conversion of cellulose into fuels alternative and value-added chemicals via different types of reactions has attracted considerable concern in both scientific and industrial communities. Nano-catalysts are showing great potential in greener processing, higher yield and selectivity’s and more favorable economics. In order to make these processes practical, environmental- friendly, and cost-competitive, the development of solid catalysis especially nanomaterials mediated catalytic systems able to operate in the aqueous phase is hence critical.Keywords: Cellulose, nanocatalysts, heterogeneous catalysis, biofuels, valuable chemicals, nanomaterials.
Graphical Abstract