| 초록 |
CO2 accumulations in the atmosphere is considered as a major contributor of global warming and greenhouse effect. To reduce the CO2 concentration, electrochemical CO2 conversion have been studied as a promising strategy due to its ambient reaction conditions, high energy efficiency, and facile combination with other renewable energy source. However, because CO2 is extremely stable, a key technology is development of suitable catalyst having good catalytic activity, selectivity, and stability. Among various materials candidates, transition and post-transition metals have been developed as electrocatalysts due to its low-cost, low-toxicity, and intrinsic catalytic property for CO2 reduction to C1 products. Herein, we developed hierarchical nanostructured Bi, and Zn electrodes as electrocatalysts for CO2 reduction to C1 products (e.g. formic acid/formate and carbon monoxide). The synthesized catalysts showed highly efficient CO2 reduction activity in terms of current density, Faradaic efficiency, and more importantly, stable performance during long-term operation. Furthermore, to understand in-depth the factors to affect the CO2 reduction, we further conducted the theoretical studies about the mechanism of CO2 conversion to C1 products depend on various Bi and Zn planes such as close-packed and high-index surfaces using density functional theory calculation (DFT). Consequently, the coordinately unsaturated sites derived from the nanostructured non-noble metal catalysts can effectively stabilize the reaction intermediate by lowering the energy barrier for its binding to the site. These results may suggest a design principle for further developments in other advanced catalysts as well as in CO2 reduction. |
