Proton affinity or transfer is crucial in determining the activity and selectivity of the electroreduction of CO 2 . However, optimizing proton supply during CO 2 reduction while simultaneously enhancing the activity of catalytic sites and inhibiting hydrogen evolution poses a significant challenge. It has been found that introduce another active site around the CO 2 reduction catalytic site to supply proton for the proton process has been proved been an effective strategy to modulate the leverage relationship in electrochemical CO 2 reduction (ECR).
A team led by Tong-Bu Lu from Tianjin University of Technology in Tianjin, China recently report a rapid strategy for preparing Cl-modified Bi nanosheets (Cl-Bi NS) by decorating the defective sites of Bi nanosheets with abundant Cl – , permitting systematical study on how Cl – impact on the catalytic activity of defective Bi sites and the proton transfer during CO 2 reduction process. It is demonstrated that rich Cl – sites around defective Bi sites could form Cl–H species during catalytic process and function as unique proton relay stations for the reaction intermediate, significantly accelerating the conversion of CO 2 -to-formate. The resulting Cl-Bi NS achieves nearly 100% formate Faradaic Efficiency (FE) at 400 mA/cm 2 and high formate FEs (> 90%) across 100 to 700 mA/cm 2 , as well as a long-term stability over 130 h in acidic electrolyte, much superior than those of Bi catalysts without Cl – modification.
In this work, for the first time, Lu et al. prepared Cl-Bi NS via a unique rapid strategy at low temperature and found that the rich Cl – sites could induce a pronounced proton feeding effect toward enhanced ECR. The results of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images and X-ray absorption fine structure (XAFS) spectroscopy, as well as in situ Raman spectroscopy verified that abundant Cl – anions were adsorbed at the defect sites of Bi nanosheets and could be rather stable during CO 2 electroreduction process. Density functional theory (DFT) calculations, in situ Raman spectroscopy and in situ attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy collectively demonstrate that Cl-Bi NS is beneficial for acidic ECR due to the Cl – at the defect sites of Bi nanosheet can form the Cl–H species and act as proton relays, and cooperate with the defective Bi sites to promote the formation of *OCHO during the conversion of CO 2 -to-fomrate. This work provides new in-depth insights for the design of efficient catalyst for CO 2 reduction.
The team published their paper in Nano Research on January 22, 2026.
This work was supported by the National Natural Science Foundation of China (No.21931007, No.21805207), National Key R&D Program of China (No.2022YFA1502902), Natural Science Foundation of the Jiangsu Higher Education Institutions (No.23KJA430001), Natural Science Foundation of Tianjin City (23JCQNJC00570).
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
Nano Research
Chloride-modified defective bismuth nanosheets providing a local proton for enhanced CO2 reduction
22-Jan-2026