Cu₃N Nanocubes for Selective Electrochemical Reduction of CO₂ to Ethylene

Abstract

Understanding the Cu-catalyzed electrochemical CO 2 reduction reaction (CO 2 RR) under ambient conditions is both fundamentally interesting and technologically important for selective CO 2 RR to hydrocarbons. Current Cu catalysts studied for the CO 2 RR can show high activity but tend to yield a mixture of different hydrocarbons, posing a serious challenge on using any of these catalysts for selective CO 2 RR. Here, we report a new perovskite-type copper(I) nitride (Cu 3 N) nanocube (NC) catalyst for selective CO 2 RR. The 25 nm Cu 3 N NCs show high CO 2 RR selectivity and stability to ethylene (C 2 H 4 ) at −1.6 V (vs reversible hydrogen electrode (RHE)) with the Faradaic efficiency of 60%, mass activity of 34 A/g, and C 2 H 4 /CH 4 molar ratio of >2000. More detailed electrochemical characterization, X-ray photon spectroscopy, and density functional theory calculations suggest that the high CO 2 RR selectivity is likely a result of (100) Cu(I) stabilization by the Cu 3 N structure, which favors CO−CHO coupling on the (100) Cu 3 N surface, leading to selective formation of C 2 H 4 . Our study presents a good example of utilizing metal nitrides as highly efficient nanocatalysts for selective CO 2 RR to hydrocarbons that will be important for sustainable chemistry/energy applications.

Imaging electrochemically synthesized Cu2O cubes and their morphological evolution under conditions relevant to CO2 electroreduction

“…Even more importantly, the highest ethylene yield was obtained when the Cu NCs/Cu samples were pretreated with an oxygen plasma which lead to a drastic change in the structure and the loss of the cubic shape after reaction, while the same samples pretreated in Ar-plasma retained the cubic structure but resulted in a significantly lower C2-C3 product selectivity. In general, the loss of Cu(100) facets is correlated with a decrease in the yield of ethylene 9,44,47 , although other factors such as the content of subsurface oxygen or Cu(I) species have also been mentioned to play a role 9,48 . Unfortunately, correlating the observed structural transformations with their impact on reaction product selectivity is still a nontrivial technical challenge for LC-TEM, and outside the scope of this work.…”

Production of C2/C3 Oxygenates from Planar Copper Nitride-Derived Mesoporous Copper via Electrochemical Reduction of CO2

“…The relatively low selectivity to products involving more than two carbon atoms, in particular C 3 products (allyl alcohol and n-propanol), also remains an issue for virtually all Cu-based catalysts. 16,[23][24][25] Although surface roughening has contributed to the selective formation of multi-carbon products on Cu, there remains a need for novel ways to produce Cu surfaces with a more controlled roughness in order 3 to clearly investigate the structure-activity relationship of CO 2 RR performances.…”

B‐Cu‐Zn‐Gasdiffusionselektroden für die elektrokatalytische CO2‐Reduktion zu C2+‐Produkten bei hohen Stromdichten

“…Die Einführung von Modifikatoren wurde als eine wirksame Strategie angesehen, um die Tendenz zur Cu + -Reduktion bei negativen Potentialen zu verringern. [19][20][21][22] Bor hat eine Elektronenkonfiguration von 2s 2 2p 1 und weist somit Lewis-Säure-Eigenschaften auf.Das leere Orbital des Bneigt dazu, Elektronen von Cu aufzunehmen, was die lokale elektronische Struktur von Cu positiver und so Lewis-saurer macht, was beides günstig ist, um die Bildung von C 2+ -Produkten in der eCO 2 RR zu fçrdern. Ein B-dotierter oxidischer Cu-Katalysator wies eine hçhere Faraday-Effizienz (FE) von 48,2 %f ürd ie Bildung von C 2+ -Produkten auf als sein borfreies Gegenstück (30,5 %), was auf die Stabilisierung der Cu + -Spezies durch die Einführung von Bzurückzuführen ist.…”