Electroreduction of CO₂ into value-added fuels is a promising strategy to meet the ever-increasing energy demands. In CO₂ electroreduction, the critical bottleneck lies in the activation of CO₂ into a radical anion, which requires a high reduction potential. A well-designed catalyst which is able to reduce the needed potential is of great need.

Recently, the research group led by Prof. ZENG Jie at University of Science and Technology of China of Chinese Academy of Sciences has made a breakthrough in the preparation of electrocatalyst which assists in the electrochemical reduction of CO₂ to fuel. The study was published in Angew. Chem. Int. Ed. 

Generally, the CO₂ activation concerns an electron transfer from catalysts to a CO₂ molecule, which was closely associated with the electronic structure of catalysts. Elemental doping into catalysts provides a promising opportunity to facilitate CO₂ activation and thereby improve the performance of CO₂ electroreduction.

Based on this strategy, researchers modified atomically thin SnS₂ nanosheets with Ni doping for enhanced performance towards CO₂ electroreduction. The Ni-doped SnS₂ nanosheets exhibited higher current density and Faradaic efficiency (FE) for carbonaceous product than those of the pristine SnS₂ nanosheets.

When the Ni content was 5 atm %, the Ni-doped SnS₂ nanosheets achieved a remarkable efficiency of 93% for carbonaceous product with a current density of 19.6 mA cm^-2 at -0.9 V vs RHE.

During the potentiostatic test, the Ni-doped SnS₂ nanosheets remained a steady FE for carbonaceous product without obvious decay of current density. Mechanistic study revealed that Ni doping generated a defect level at conduction band edge and decreased the work function of SnS₂ nanosheets, which benefited the activation of CO₂ and accordingly improved the catalytic performance in CO₂ electroreduction.

This work not only demonstrated Ni-doped SnS₂ nanosheets as promising catalysts for CO₂ electroreduction, but also provided a strategy for the design of electrocatalysts, which may further be widely applied to energy industry.

The mapping spectra of Ni doped SnS₂ nanosheets and the electrochemical performances for CO₂ reduction. (Image by ZENG Jie)