Selective electroreduction of CO2 to acetone by single copper atoms anchored on N-doped porous carbon

Kun Zhao,Shuo Chen,Wonyong Choi,Bupmo Kim,Jingguang G Chen,Hongtao Yu,Xie Quan,Xiaowa Nie,Haozhi Wang,Guanghui Zhang

doi:10.1038/s41467-020-16381-8

Abstract

Efficient electroreduction of CO2 to multi-carbon products is a challenging reaction because of the high energy barriers for CO2 activation and C–C coupling, which can be tuned by designing the metal centers and coordination environments of catalysts. Here, we design single atom copper encapsulated on N-doped porous carbon (Cu-SA/NPC) catalysts for reducing CO2 to multi-carbon products. Acetone is identified as the major product with a Faradaic efficiency of 36.7% and a production rate of 336.1 μg h−1. Density functional theory (DFT) calculations reveal that the coordination of Cu with four pyrrole-N atoms is the main active site and reduces the reaction free energies required for CO2 activation and C–C coupling. The energetically favorable pathways for CH3COCH3 production from CO2 reduction are proposed and the origin of selective acetone formation on Cu-SA/NPC is clarified. This work provides insight into the rational design of efficient electrocatalysts for reducing CO2 to multi-carbon products.

Highlights

Efficient electroreduction of CO2 to multi-carbon products is a challenging reaction because of the high energy barriers for CO2 activation and C–C coupling, which can be tuned by designing the metal centers and coordination environments of catalysts
The NPC only showed the signal of C, N, and O elements (Supplementary Fig. 1), while the Cu-SA/NPC exhibited a small peak of Cu, indicating that Cu was successfully incorporated in the prepared material
CH3COCH3 generation increased and reached to a maximum value of 36.7% at −0.36 V, which was 11.2 and 12.7 times as great as those for CH3OH and C2H5OH, respectively. Both the production rate and Faradaic efficiency of acetone generation on Cu-SA/NPC were significantly enhanced as compared with other electrocatalysts reported in the literature[32,33]

Summary

Introduction

Efficient electroreduction of CO2 to multi-carbon products is a challenging reaction because of the high energy barriers for CO2 activation and C–C coupling, which can be tuned by designing the metal centers and coordination environments of catalysts. Numerous electrocatalysts have been designed for CO2 reduction, such as metals, metal oxides, and carbon-based materials[10,11,12,13,14] Among these catalysts, copper (Cu) owns the ability to generate multi-carbon products from CO2 reduction. Copper (Cu) owns the ability to generate multi-carbon products from CO2 reduction This may be related to the optimal binding energy of CO intermediate on Cu, leading to the further reduction of CO intermediate and achieving the C–C coupling[12,15,16,17]. Single atom catalysts (SAC) with atomically distributed active metal centers have been demonstrated to possess enhanced activity and tunable selectivity toward CO2 reduction due to its maximum atom utilization efficiency, unique electronic structure, and unsaturated coordination environment of metal centers[22,23,24]

Methods

Results

Conclusion