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)
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