Nanomaterial-Decorated Biomass-Derived Carbon for Electrochemical Sensing: Design Principles, Interfacial Mechanisms,...

The increasing demand for highly sensitive and reliable electrochemical sensors (ESs) has driven the development of advanced electrode materials with enhanced catalytic activity and structural tunability. Biomass-derived carbon (BDC) has emerged as a promising platform owing to its natural abundance, low cost, hierarchical porosity, and sustainable synthesis routes. However, pristine BDC often suffers from limited electrical conductivity and insufficient active sites, which can restrict electron-transfer kinetics and compromise sensing performance. Integrating functional nanomaterials with BDC frameworks offers an effective strategy to overcome these limitations and significantly improve electrochemical sensing efficiency. This review presents an overview of nanomaterial-decorated BDC systems for electrochemical sensing applications, including hybrid architectures incorporating metal nanoparticles, metal oxides, hydroxides, sulfides, heteroatom-doped structures, and conducting polymers. We discuss how synthesis strategies, structural characteristics, electronic properties, and defect engineering influence key analytical parameters such as sensitivity, selectivity, detection limit, linear response range, stability, and reproducibility. Particular emphasis is placed on interfacial charge-transfer mechanisms between nanomaterials, BDC frameworks, and target analytes. Current challenges including nanoparticle aggregation and active-site blockage are discussed, and emerging design strategies are highlighted to guide the development of scalable and high-performance BDC-based electrochemical sensing platforms.