Noble metal nanoparticles dispersed on nanocellulose: a green platform for catalytic organic transformations

Abstract

In recent years, plant-derived biomaterials, typically cellulose, acting as catalytic supports have a great impact on heterogeneous catalysis thanks to their biodegradability, non-toxicity, low-cost, availability and easy-implementation. As the most abundant biopolymer found in nature, cellulose consists of repeating cellobiose units which are built up from two anhydroglucose rings and linked by a β-1,4 glycosidic bond. The term of “nanocellulose” has been widely used to describe cellulose nano-objects, involving cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs) and bacterial cellulose (BC). Nanocellulose features high specific surface area and controllable surface chemistry, high crystalline structure, superior mechanical strength and thermal stability, resulting in its applications in food, cosmetics, pharmaceutical, biomedical and paper industries. Concerning to catalytic support application, the nanocellulose surface possesses the hydroxyl (in nature) or the sulfate ester groups (modified via acid hydrolysis), facilitating metal ions reduction towards the corresponding metal nanoparticles. In addition, the supramolecular structure of cellulose permits to disperse metal nanoparticles and prevent their agglomerations. In this context, nanocellulose is introduced as matrices for immobilizing noble metal nanoparticles and then applied to catalytic organic transformations.