Recent Advances in Application of Polyoxometalates in Lignocellulose Pretreatment and Transformation

Abstract

Lignocellulose, composed of cellulose, hemicellulose, and lignin, holds immense promise as a renewable resource for the production of sustainable chemicals and fuels. Unlocking the full potential of lignocellulose requires efficient pretreatment strategies. In this comprehensive review, efforts were taken to survey the latest developments in polyoxometalates (POMs)-assisted pretreatment and conversion of lignocellulosic biomass. An outstanding finding highlighted in this review is that the deformation of the cellulose structure from I to II accompanied by the removal of xylan/lignin through the synergistic effect of ionic liquids (ILs) and POMs resulted in a significant increase in glucose yield and improved cellulose digestibility. Furthermore, successful integration of POMs with deep eutectic solvents (DES) or γ-valerolactone/water (GVL/water) systems has demonstrated efficient lignin removal, opening avenues for advanced biomass utilization. This review not only presents the key findings and novel approaches in POMs-based pretreatment but also addresses the current challenges and prospects for large-scale industrial implementation. By offering a comprehensive assessment of the progress in this field, this review serves as a valuable resource for researchers and industry professionals aiming to harness the potential of lignocellulosic biomass for sustainable chemical and fuel production.

Ionic liquid-stabilized metal oxoclusters: from design to catalytic application

“…It has been demonstrated that POMs can effectively promote the dissolution of wood in ILs while concurrently reducing the lignin content in the resultant cellulose-rich pulp. 103,104 It's noteworthy that POMs do not completely degrade lignin into low molecular weight fragments, and they can be reoxidized under mild conditions in IL, albeit with some loss in POM and activity. Importantly, different POM species affect significantly the efficiency of delignification.…”

Polyoxometalate as an Effective Catalyst for Catalytic Lignin into Value‐Added Molecules

“…For a more in-depth discussion of this topic, readers are urged to consult the following reviews. [2,[25][26][27][28] The Keggin type of POM, also known as heteropoly acid (HPA), garners significant interest due to its unique composition of a central tetrahedron XO 4 O 40 ). These acids are extensively utilized in the delignification of lignocellulosic pulp and as redox catalysts for the hydrogenolysis/hydrodeoxygenation (HDO) of lignin.…”