Highly dispersed CuFe-nitrogen active sites electrode for synergistic electrochemical CO2 reduction at low overpotential
2020
Wang, Fuhuan | Xie, Heping | Liu, Tao | Wu, Yifan | Chen, Bin
The electrochemical conversion of carbon dioxide into value-added chemicals and fuels using renewable energy sources is very promising and attractive in terms of both increasing energy utilization and environmental protection. Here we report a highly dispersed CuFe nitrogen–carbon framework as an efficient catalyst coated on carbon paper to form gas diffusion electrode for electrochemical CO₂ reduction. Such a electrode not only surmounts the disadvantage of single Cu or Fe electrode but also exhibits high selectivity, low overpotential and high energy efficiency for CO production. The as-fabricated electrode effectively converts CO₂ into CO with a low overpotential of 90 mV and high Faradaic efficiency over 90% at low applied potential range from −0.3 to −0.6 V (maximum 95.5% at −0.4 V, all potentials are converted to the reversible hydrogen electrode) with a high CO current density of 2.1 mA cm⁻² at −0.5 V, as well extremely high energy efficiency of 78.3% at −0.4 V. It also exhibits robust stability during long-time electrolysis, with about 95% CO selectivity retained after 20 h electrolysis. The density functional theory computations unravel that the exceptionally high CO₂ electrocatalytic performance of the CuFe nitrogen–carbon electrode arises from its favorable local coordination environment and electronic structure giving rise to cooperative metal and pyridine N active sites for electrochemical CO₂ reduction to CO.
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