Selectivity Switching of CO<sub>2</sub> Hydrogenation from HCOOH to CO with an <i>In Situ</i> Formed Ru–Li Complex
Qiongyao Chen, Chaoren Shen, Gangli Zhu, Xuehua Zhang, Chunlin Lv, Bo Zeng, Sen Wang, Junfen Li, Weibin Fan, Lin He
Abstract
Herein, we report the role of alkali halide salt in regulating the pathway of CO2 hydrogenation in the presence of Shvo’s complex. Particularly, the collaboration of Shvo’s complex with LiCl exhibited as a highly efficient catalyst for CO2 hydrogenation to CO instead of the kinetically favorable product HCOOH under mild conditions. The reaction can be initiated at 45 °C with CO as the dominant product, and the rate of CO formation was almost 80 times to that in the absence of LiCl at 60 °C. Under optimized conditions, the TONCO could reach 1555 at 160 °C, much higher than the reported results of the most efficient Ru-based homogeneous catalyst. Density functional theory calculations demonstrated that the cooperation of the alkali cation and chloride anion contributed to reducing the energy barrier of CO2 activation to form the key Ru–CO2H intermediate. An in situ formed mixed Ru–Li complex (5) has been characterized by X-ray crystallography, highlighting the indispensability of electrostatic interactions between LiCl and Shvo’s complex for enhanced reactivity and altered selectivity.