Carbon-Based Heterogeneous Catalysis for Biomass Conversion to Levulinic Acid: A Special Focus on the Catalyst

Abstract

The conversion of cellulosic biomass into renewable chemicals can serve as a sustainable resource for levulinic acid production (LA). LA yield is significantly influenced by reaction temperature, reaction time, substrate concentration, active sites, catalyst amount, catalyst porosity, and durability. Beyond the features of the catalyst, such as acidity, porosity, functional groups, and catalytic efficiency, the contact between the solid acid catalyst and the solid substrate is of vital importance. Solid-based catalysts show remarkable catalytic activity for LA production from cellulose, thanks to the incorporation of functional groups. For a solid carbon-based catalyst to be effective, a synergistic interaction between the binding domain (functional groups capable of anchoring cellulose to the catalyst surface, such as chloride groups, COOH, or OH) and the hydrolysis domain (due to their ability to cleave glycosidic bonds, such as SO3H) is essential. As a relatively new market niche, carbon-based catalyst supports are projected to reach a market value of nearly USD 125 million by 2030. This review aims to highlight the advantages and limitations of carbon-based materials compared to conventional catalysts (including metal oxides or supported noble metals among others) in features like catalytic activity, thermal stability, cost, examine recent advancements in catalyst development, and identify key challenges and future research directions to enable more efficient, sustainable, and scalable processes for LA production. The novelty of this review lies in the carbon-based catalyst for LA production, emphasizing its physical and chemical characteristics.