Fine-Tuned Charge Density of Pt Single-Atom Sites for Controllable Hydrodeoxygenation of Lignin

Achieving high-selectivity conversion of lignin to value-added chemicals and biofuels remains a desirable but challenging target due to its complex structure with multiple reaction paths. Herein, we designed the robust Pt single-atom sites supported on NiAl layered double hydroxide (Pt₁/NiAl-LDH) and intermetallic compound (Pt₁/NiAl-IMC) with distinct local charge density for selectivity-controllable hydrodeoxygenation of lignin. The Pt₁/NiAl-LDH with electron-deficient Pt sites hydrogenated 4-propylguaiacol into 4-propylcyclohexanol with 100% conversion and over 90% selectivity, while Pt₁/NiAl-IMC with electron-rich Pt sites favored complete deoxygenation, yielding almost equivalent of propylcyclohexane. Similar results were achieved using lignin samples. Density functional theory calculations revealed that the deoxygenation capacity of Pt₁/NiAl-IMC stems from the high electronic density of Pt single atoms, which injects electrons into the C─O bond and weakens its bonding energy. This study demonstrates that the catalytic performance of single-atom catalysts in biopolymers hydrodeoxygenation can be optimized toward different products by well-controlled electronic structures.