Monodisperse Condensed Tannin and Derived Carbon Nanospheres Featuring Well‐Defined Surface‐Structured Metal Species

ABSTRACT Direct synthesis of monodispersed nanospheres from heterogeneous biopolymers remains a current challenge within materials science. Here, we introduce the assembly of uniform and size‐tunable condensed tannin (proanthocyanidin) nanospheres (TNSp) via a hydrogen bonding‐driven hydrophobic assembly that takes place in aqueous medium and ambient conditions. Uniform particles are formed by a gradual increase in tannin‐amine concentrations in the reaction system, which regulates nucleation and growth via supramolecular interactions. The phenolic‐amine rich surface of the nanospheres allows a precise structuring of metal species ( e.g ., Pt, Co, Ni), thus ensuring high dispersion, uniform particle size, and suppressed sintering of the metal species (1–2 nm) during pyrolysis. Derived carbon particles with surface‐anchored Pt nanoparticles (Pt‐TNSpC) are then demonstrated as high performance catalysts in the electro‐hydrogenation of guaiacol, holding performance surpassing that of Pt/C catalyst. Nevertheless, life cycle assessment revealed a significantly lower carbon footprint against benchmark catalysts (1770 kg CO 2 ‐eq.·kg −1 vs. 11510–82660 kg CO 2 ‐eq.·kg −1 ), alongside enhanced material circularity. This work establishes a sustainable strategy for converting renewable biobased feedstocks into precision nanostructured particles for high performance catalysis. We envision these metal‐functionalized tannin‐derived particles to find use in various fields in which metallic functionalities play a role.