Nanostructured ceria-based catalysts for the conversion of lignocellulosic biomass to fuels and chemicals

The synthesis of alternative chemicals and fuels is vital in view of abnormal climate change and rapidly decreasing fossil fuel sources. The inherent hydrocarbon structure of renewable biomass enables it a promising alternative source to fossil fuels. The application of a diverse heterogeneous catalyst can selectively convert biomass-based molecules into valuable chemicals and biofuels at mild reaction conditions. Ceria is a widely used material in heterogeneous catalysis because of its notable hydrothermal stability, superior redox nature as well as adequate acid-base properties. Several advanced strategies have been developed to enrich the redox and catalytic properties of ceria by tuning its morphology, structure, and surface crystal planes as well as doping/addition of appropriate metals. This review elucidates the recent developments in the conversion of lignocellulosic biomassbased molecules using nanostructured ceria-based catalysts. The role of Ce4+/Ce3+ and oxygen vacancies as well as the effect of metal doping and metal-ceria interfaces in activating carbohydrates (glucose and fructose), furans (5-HMF and furfural), and lignin-based aromatics are highlighted with detailed structure-activity, mechanistic, and theoretical studies. The prospects and challenges toward practically viable production of biomass-derived chemicals and fuels using ceria-based catalysts are emphasized.