A New Strategy for Accelerating Dynamic Proton Transfer of Electrochemical CO2 Reduction at High Current Densities. (9th September 2021) - Wang, Xinyue
Abstract: Developing single‐atom electrocatalysts with high activity and superior selectivity at a wide potential window for CO2 reduction reaction (CO2 RR) still remains a great challenge. Herein, a porous NiNC catalyst containing atomically dispersed NiN4 sites and nanostructured zirconium oxide (ZrO2 @Ni‐NC) synthesized via a post‐synthetic coordination coupling carbonization strategy is reported. The as‐prepared ZrO2 @Ni‐NC exhibits an initial potential of −0.3 V, maximum CO Faradaic efficiency (F.E.) of 98.6% ± 1.3, and a low Tafel slope of 71.7 mV dec −1 in electrochemical CO2 RR. In particular, a wide potential window from −0.7 to −1.4 V with CO F.E. of above 90% on ZrO2 @Ni‐NC far exceeds those of recently developed state‐of‐the‐art CO2 RR electrocatalysts based on NiN moieties anchored carbon. In a flow cell, ZrO2 @Ni‐NC delivers a current density of 200 mA cm −2 with a superior CO selectivity of 96.8% at −1.58 V in a practical scale. A series of designed experiments and structural analyses identify that the isolated NiN4 species act as real active sites to drive the CO2 RR reaction and that the nanostructured ZrO2 largely accelerates the protonation process of *CO2 − to *COOH intermediate, thus significantly reducing the energy barrier of this rate‐determining step and boosting whole catalytic performance. Abstract : An atomically dispersed nickel site anchored on a nitrogen‐doped porous carbon skeleton coupled with nanostructured zirconium oxide is developed for highly efficient CO2 reduction to produce CO.