Single‐Unit‐Cell Catalysis of CO<sub>2</sub> Electroreduction over Sub‐1 nm Cu<sub>9</sub>S<sub>5</sub> Nanowires
Deren Yang, Shouwei Zuo, Haozhou Yang, Xun Wang
Abstract
Abstract As a bridge between nanocrystal catalysts and single‐atom catalysts, single‐unit‐cell catalysts seem at first glance to be unavailable for catalysis due to quantum effects and synthetic difficulties. Here, 24 nm Cu 9 S 5 nanowires are synthesized via the LaMer pathway. Interestingly, when polyoxometalate (POM) clusters are introduced during the nucleation process, the 0.9 nm Cu 9 S 5 nanowires are finally formed via covalent co‐assembly, analog to A–B–A–B‐type block co‐polymerization in the polymer field (“A” and “B” represent Cu 9 S 5 unit cells and POM clusters, respectively). Multiple characterizations show that Cu 9 S 5 exists as single‐unit‐cell structure. Therefore, each unit cell can work as an isolated active site. The single‐unit‐cell structure exhibits higher electrocatalytic activity and Faradaic efficiency (FE) of formic acid (82.0% at −0.8 V vs reversible hydrogen electrode (RHE)) during CO 2 electroreduction, while the nanocrystal structure generates HCOO − , methanol, and ethanol with low FEs. This study suggests that the single‐unit‐cell catalyst displays great potential for precise catalysis by the finite size effect.