Interface-Enhanced Catalytic Selectivity on the C₂ Products of CO₂ Electroreduction

Abstract

Powered by renewable electricity, the electrochemical conversion of CO2 to liquid fuels and valuable chemicals is a meaningful approach to enable carbon cycling and tackle environmental issues. An intrinsic challenge has been the low efficiency and selectivity, in particular for deep reduction products. Here, we report on an interface-enhanced strategy for transforming the catalytic selectivity toward the CO2 reduction reaction (CO2RR). Inspired by the enzyme catalysis in nature, where the catalytic center is surrounded by a chemically selective environment, we create a thin layer of nitrogen-doped carbon (N x C) over the Cu surface. The N x C environment does not modify the electronic property of Cu but selectively enriches and activates CO2 molecules through the specific N–CO2 interaction, as experimentally identified. Such a Cu/N x C interface has boosted the faradic efficiency (FE) of the CO2RR to be above 90%, with the C2 products (ethylene and ethanol) being the majority (80% in total FE). The N x C overlayer also protects well the Cu substrate from the morphological change, thus increasing the catalytic stability. Our findings manifest that the chemical environment over the metal surface indeed plays a crucial, but not well recognized, role in selectivity control, which can hardly be achieved by solely tuning the electronic structure of metal catalysts.

Investigating the Effect of the Initial Valence States of Copper on CO2 Electroreduction

“…CO is believed to be the dominant intermediate to form C 2+ products during CO 2 ERR [30] . The peak potentials of CO are shifted from −1.2 V on CuO/C, to −0.9 V on Cu 2 O/C and −0.7 V on Cu/C.…”

Anchoring Ionic Liquid in Copper Electrocatalyst for Improving CO2 Conversion to Ethylene

“…Great efforts have been devoted to the development of electrocatalysts for improving C 2 H 4 production from CO 2 RR, including crystal plane adjustment, [4,5] defect engineering, [6] alloying, [7][8][9] valence regulation [10] and surface molecule modification. [11][12][13] Among the cathode metals applied, Cu has been the predominant electrocatalytic material. At present, the highest Faradaic efficiency (FE) of C 2 H 4 is 87 % at À 0.47 V versus the reversible hydrogen electrode (vs. RHE), which was achieved by a Cu-polyamine hybrid catalyst conducting in a flow reactor, with a gas diffusion layer as cathode.…”

MOF Encapsulating N‐Heterocyclic Carbene‐Ligated Copper Single‐Atom Site Catalyst towards Efficient Methane Electrosynthesis

“…By contrast, the peaks referred to OH deformation, asymmetric stretching of COOH* and OCH 3 * on 2Bn‐Cu@UiO‐67 are more notable than that on 2Bn‐ACu@UiO‐67, indicating that abundant CH 4 intermediates are consumed on their surfaces (Figure 4 b). Notably, only the signal of intermediate symmetric stretch (COOH*) on 2Bn‐Cu@UiO‐67 shows a blue shift with the increase of potential, indicating that the observed COOH* is a surface species rather than a molecule dissolved in the solution [22] . Based on the in situ ATR‐SEIRAS analysis, we can conclude, that CH 4 is most likely generated on 2Bn‐Cu@UiO‐67.…”