Electrochemical reduction of CO2 to valuable fuels and feedstocks is appealing for CO2 fixation and energy storage. However, the development of electrocatalysts with high activity and selectivity in a wide potential window remains challenging.
As a newly emerging two-dimensional(2D) material, the metallenes with ultrathin morphology will enable a superhigh atomic utilization for catalysis, leading to the partial homogenization of such heterogeneous catalysts, presenting great potentials in electrocatalytic CO2 reduction reaction (CO2RR). Nevertheless, the synthesis of ultrathin metallenes by chemical ways is attractive but difficult.
In a recent study published in Angew. Chem. Int. Ed., a group led by Prof. ZHU Qilong from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences reported a facile in situ electrochemical transformation way to synthesize the atomically thin bismuthine (Bi-ene) electrocatalyst from metal–organic layers (MOLs) for CO2RR.
The researchers found that the average thickness of the as-prepared Bi-ene is only 1.28–1.45 nm, corresponding to about 3–4 layers, which is among the thinnest Bi nanosheets reported to date.
When used as working electrode in electrolytic CO2RR process, the few-layer Bi-ene, which possesses a great mass of exposed active sites with high intrinsic activity, has a high selectivity (ca. 100%), large partial current density (72.0 mA cm–2), and quite good stability in a potential window exceeding 0.35 V toward formate production.
By using a self-designed flow cell, Bi-ene can deliver exceptional current densities larger than 300 mA cm–2 without compromising the selectivity of formate production, preliminarily meeting the requirements for commercial application.
In situ ATR-IR spectra and DFT analysis revealed a new reaction mechanism involving HCO3–for formate generation, which is different from the general thought that HCO3– groups are used as proton source or act as the mediator to deliver CO2 to catalyst surface to accelerate reaction during CO2RR process.
This study opens up a new way to develop high-performance CO2RR electrocatalysts and metallene electrocatalysts and provides a new sight into the CO2RR process, which would be beneficial for researchers to develop more high-efficiency CO2RR system.
Figure: In situ formation of bismuthene (Bi-ene) and its utilization in electrolytic CO2RR. (Image by Prof. ZHU’s Group)
Contact:
Prof. ZHU Qilong
Fujian Institute of Research on the Structure of Matter
Chinese Academy of Sciences
Email: qlzhu@fjirsm.ac.cn
