Optimizing reaction paths for methanol synthesis from CO<sub>2</sub> hydrogenation via metal-ligand cooperativity.

Chen, Yizhen; Li, Hongliang; Zhao, Wanghui; Zhang, Wenbo; Li, Jiawei; Li, Wei; Zheng, Xusheng; Yan, Wensheng et al. · Nat Commun · 2019

basic_science · Level V

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Abstract

As diversified reaction paths exist over practical catalysts towards CO<sub>2</sub> hydrogenation, it is highly desiderated to precisely control the reaction path for developing efficient catalysts. Herein, we report that the ensemble of Pt single atoms coordinated with oxygen atoms in MIL-101 (Pt<sub>1</sub>@MIL) induces distinct reaction path to improve selective hydrogenation of CO<sub>2</sub> into methanol. Pt<sub>1</sub>@MIL achieves the turnover frequency number of 117 h<sup>-1</sup> in DMF under 32 bar at 150 °C, which is 5.6 times that of Pt<sub>n</sub>@MIL. Moreover, the selectivity for methanol is 90.3% over Pt<sub>1</sub>@MIL, much higher than that (13.3%) over Pt<sub>n</sub>@MIL with CO as the major product. According to mechanistic studies, CO<sub>2</sub> is hydrogenated into HCOO* as the intermediate for Pt<sub>1</sub>@MIL, whereas COOH* serves as the intermediate for Pt<sub>n</sub>@MIL. The unique reaction path over Pt<sub>1</sub>@MIL not only lowers the activation energy for the enhanced catalytic activity, but also contributes to the high selectivity for methanol.