Integrated Biomass Valorization: From Platform Molecules to Functional Carbon Materials for Sustainable Energy and Environmental Applications.

The increasing demand for sustainable alternatives to fossil-based resources has intensified interest in the integrated valorization of lignocellulosic biomass within the context of biorefinery and circular economy strategies. However, the relationship between biomass-derived platform molecules and biomass-derived carbonaceous materials remains insufficiently explored in the literature. This review discusses recent advances in the conversion of biomass into platform molecules, particularly furfural and 5-hydroxymethylfurfural (HMF), with emphasis on catalytic pathways and the role of homogeneous, heterogeneous, and biomass-derived catalysts in controlling process selectivity and efficiency. Representative studies reporting HMF yields above 90% and recyclable biomass-derived catalysts are highlighted to demonstrate the potential of sustainable catalytic approaches. In parallel, the synthesis of biomass-derived carbonaceous materials via pyrolysis and hydrothermal carbonization is discussed, together with surface functionalization strategies involving sulfonic, amino, and phosphate groups. These modifications enable the development of multifunctional materials for applications in catalysis, electrochemical systems, and adsorption processes. Furthermore, the review highlights the integrated role of biomass as both feedstock and catalyst precursor, reinforcing the concept of closed-loop biomass valorization. Finally, current challenges related to catalyst stability, process scalability, and sustainable industrial implementation are critically discussed.