Efficient electron transmission in covalent organic framework nanosheets for highly active electrocatalytic carbon dioxide reduction.

Zhu, Hong-Jing; Lu, Meng; Wang, Yi-Rong; Yao, Su-Juan; Zhang, Mi; Kan, Yu-He; Liu, Jiang; Chen, Yifa et al. · Nat Commun · 2020

basic_science · Level V

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Abstract

Efficient conversion of carbon dioxide (CO<sub>2</sub>) into value-added products is essential for clean energy research. Design of stable, selective, and powerful electrocatalysts for CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) is highly desirable yet largely unmet. In this work, a series of metalloporphyrin-tetrathiafulvalene based covalent organic frameworks (M-TTCOFs) are designed. Tetrathiafulvalene, serving as electron donator or carrier, can construct an oriented electron transmission pathway with metalloporphyrin. Thus-obtained M-TTCOFs can serve as electrocatalysts with high FE<sub>CO</sub> (91.3%, -0.7 V) and possess high cycling stability (>40 h). In addition, after exfoliation, the FE<sub>CO</sub> value of Co-TTCOF nanosheets (~5 nm) is higher than 90% in a wide potential range from -0.6 to -0.9 V and the maximum FE<sub>CO</sub> can reach up to almost 100% (99.7%, -0.8 V). The electrocatalytic CO<sub>2</sub>RR mechanisms are discussed and revealed by density functional theory calculations. This work paves a new way in exploring porous crystalline materials in electrocatalytic CO<sub>2</sub>RR.