Nanolignin from lignocellulosic biomass in heterogeneous catalytic reactions: Toward sustainable processes

Abstract

Lignocellulosic biomass is an attractive raw material due to its low cost, high availability, reactivity, functionality, and biodegradability. Therefore its valorization could contribute to the sustainable development goals by producing value-added products. Nanolignin functional groups are carboxylic, phenolic, and hydroxyl groups, and their amount is higher than that of “traditional-sized” lignin. These functional groups can interact with the surrounding medium through physical or chemical surface interactions π-π stacking, electrostatic interactions, and (or) hydrogen bonds. The surface properties of nanolignin can be modified according to its final use as a catalyst. Doping, surface modification, and functionalization of nanolignin have been widely applied to improve its properties such as selectivity, stability, reactivity, and reusability for several final applications. The conversion of lignin in heterogeneous nanocatalysts presents several challenges that need to be addressed to improve the efficiency and sustainability of the process. One of the main challenges is lignin´s recalcitrance and heterogeneity, which makes it difficult to depolymerize and convert into value-added chemicals and fuels. The conversion of lignin in heterogeneous nanocatalysts presents several challenges that need to be addressed to improve the efficiency and sustainability of the process. Efficient and sustainable heterogeneous catalyst development, optimization of reaction conditions, and the integration of biorefinery systems are crucial for sustainable lignin conversion. Understanding the key catalyst design principles is essential for advancing the field and achieving sustainable lignin valorization.