Ligand Tuning of Molecular Ag Catalysts Enables Efficient Direct Propylene Electrooxidation to Propylene Glycol

作者：Xi Wang, Simin Xu, An-Zhen Li, Bo‐Jun Yuan, Qiujin Shi, Xiang Liu, M. Xu, Yuanbo Liu, Kejian Kong, Chunyu Zhang, Ruo-Pu Li, Cheng Tang, Zhuo Chen, Bi‐Jie Li, Haohong Duan · 发表于：Journal of the American Chemical Society · 年份：2025 · DOI：10.1021/jacs.5c06198 · 被引用次数：13 · 研究领域：Electrocatalysts for Energy Conversion、Catalytic Processes in Materials Science、CO2 Reduction Techniques and Catalysts

Renewable-electricity-driven direct oxidation of propylene (C 3 H 6 ) presents a sustainable route for propylene glycol (PG) production. Silver (Ag) shows a 30-fold lower price compared to other active noble metals (platinum and palladium) but suffers from low activity. Here, we report a ligand-tuning strategy in Ag-based molecular catalysts for efficient direct C 3 H 6 -to-PG conversion. By broad ligand screening, Ag chelated with phenanthroline (phen) and supported on a carbon nanotube (Ag-phen/CNT) was identified to display superior performance. Mechanistic studies revealed that the electron-donating ability of phen facilitated the formation of high-valence Ag-oxo species, which served as the rate-determining step for C 3 H 6 oxidation. Based on the promoting role of the electron-donating effect on catalytic performance, substituents with diverse electron-donating and -withdrawing properties were introduced to the phen’s scaffold. As a result, a linear correlation between the logarithm of the reaction rate and Hammett constants of the substituents was revealed. Based on this correlation, Ag chelated with dimethoxy-substituted phen (Ag-OMe-phen/CNT) was discovered as a more efficient catalyst. In a three-compartment flow cell under a current density of 50 mA cm –2, this catalyst exhibited high PG productivity (432.8 μmol cm –2 h –1 ), FE (46.5%), selectivity (97.1%), and turnover frequency (73.0 min –1 ), outperforming previous Ag-based catalysts and is superior to state-of...