Understanding the Effect of *CO Coverage on C–C Coupling toward CO₂ Electroreduction

Abstract

Cu-based tandem nanocrystals have been widely applied to produce multicarbon (C 2+ ) products via enhancing CO intermediate (*CO) coverage toward CO 2 electroreduction. Nevertheless, it remains ambiguous to understand the intrinsic correlation between *CO coverage and C−C coupling. Herein, we constructed a tandem catalyst via coupling CoPc with the gas diffusion electrode of Cu (GDE of Cu−CoPc). A faradaic efficiency for C 2+ products of 82% was achieved over a GDE of Cu−CoPc at an applied current density of 480 mA cm −2 toward CO 2 electroreduction, which was 1.8 times as high as that over the GDE of Cu. Based on in situ experiments and density functional theory calculations, we revealed that the high *CO coverage induced by CO-generating CoPc promoted the local enrichment of *CO with the top adsorption mode, thus reducing the energy barrier for the formation of OCCO intermediate. This work provides an in-depth understanding of the surface coverage-dependent mode-specific C−C coupling mechanism toward CO 2 electroreduction.

Mechanistic Insights into OC–COH Coupling in CO2 Electroreduction on Fragmented Copper

“…23,24 The stronger *CO adsorption may lead to the high coverage of *CO, thus decreasing the reaction energies of C−C coupling (Figure S1b,c). 24,25 Besides, the adsorption energy of *COH also increases with the decreased CNs.…”

Tandem electrocatalytic CO2 reduction with Fe-porphyrins and Cu nanocubes enhances ethylene production

“…Recent studies have suggested that CO-producing molecular catalysts are alternative candidates to metals in tandem schemes. [25][26][27] Molecular components offer additional versatility compared to metals because their electronic and structural features can be tuned via synthetic modications. [28][29][30][31] While the examples are still limited, studies in the literature on tandem catalysts including CO-producing molecular catalysts and Cu are encouraging.…”

“…[28][29][30][31] While the examples are still limited, studies in the literature on tandem catalysts including CO-producing molecular catalysts and Cu are encouraging. [25][26][27] For example, the addition of either an iron porphyrin or a cobalt phthalocyanine to sputtered Cu resulted in enhanced C 2+ product yields. 25,26 Specically, the coupling of iron porphyrin with sputtered Cu resulted in increased faradaic efficiency for ethanol from 29% to 41% and in a shi the detection potential of this product from −0.84 to −0.82 V vs. RHE.…”

“…[25][26][27] For example, the addition of either an iron porphyrin or a cobalt phthalocyanine to sputtered Cu resulted in enhanced C 2+ product yields. 25,26 Specically, the coupling of iron porphyrin with sputtered Cu resulted in increased faradaic efficiency for ethanol from 29% to 41% and in a shi the detection potential of this product from −0.84 to −0.82 V vs. RHE. 25 The cobalt phthalocyanine/Cu catalyst enhanced the faradaic efficiency for C 2+ products from 45% to 82% in a highly basic electrolyte.…”

Enhancing CO2 Electroreduction Selectivity toward Multicarbon Products via Tuning the Local H2O/CO2 Molar Ratio

“…The electroreduction of CO 2 , driven by renewable electricity, paves a promising avenue to converting CO 2 into value-added chemicals and feedstocks for reducing the net CO 2 emission. − Until recently, many kinds of products, such as carbon monoxide (CO), formate (HCOO – ), methane (CH 4 ), ethylene (C 2 H 4 ), ethanol (C 2 H 5 OH), and acetate (CH 3 COO – ), have been obtained during CO 2 electroreduction. − Among all the carbonaceous products derived from CO 2 electroreduction, multicarbon (C 2+ ) products have drawn incredible attention as a result of the high energy density and unique chemical functional groups. − At present, Cu-based materials are considered to be the most promising catalysts for producing C 2+ products because of the moderate binding of reaction intermediates on the surface of Cu. , Hence, it is of great importance to develop highly efficient Cu-based catalysts for improving the activity of C 2+ products.…”