Catalytic Refining Lignin‐derived Monomers: Seesaw Effect between Nanoparticle and Single‐Atom Pt

Pt automatically adsorbed on oxygen vacancy of TiO 2 via an in situ interfacial redox reaction, resulting in atomically dispersion of Pt on TiO 2 . In the upgrading of lignin‐derived 4 ‐propylguaiacol, single‐atom catalyst (SAC) Pt/TiO 2 −H achieved a conversion of 96.9 % and a demethoxylation selectivity of 93.3 % under 3 MPa H 2 at 250 °C for 3 h, markedly different from the performance of nanoparticle counterpart that gave deep deoxygenation selectivity over 99.0 %. The high demethoxylation activity of SAC Pt/TiO 2 −H is mainly attributed to its weak hydrogen spillover capacity that suppressed the benzene ring hydrogenation and the deep deoxygenation. Additionally, SAC Pt/TiO 2 −H reduced the energy barrier of C Ar −OCH 3 bond cleavage and accordingly lowered the Gibbs free energy of the demethoxylation reaction. This facile method could fabricate single‐atom Au, Pd, Ir, and Ru supported on TiO 2 −H, demonstrating the generality of this strategy for the establishment of a library of SACs. Moreover, SAC exhibited versatile capacity in demethoxylation of different lignin‐derived monomers and high stability. This study showcases the superiority of atomically dispersed metal catalysts for selective demethoxylation reactions and proposes a renewable alternative to fossil‐based 4‐alkylphenols through upgrading of lignin‐derived monomers.