Facet‐Selective Deposition of Ultrathin Al₂O₃ on Copper Nanocrystals for Highly Stable CO₂ Electroreduction to Ethylene

Abstract

Catalysts based on Cu nanocrystals (NCs) for electrochemical CO 2 -to-C 2+ conversion with high activity have been a subject of considerable interest, but poor stability and low selectivity for a single C 2+ product remain obstacles for realizing sustainable carbon-neutral cycles. Here, we used the facet-selective atomic layer deposition (FS-ALD) technique to selectively cover the (111) surface of Cu NCs with ultrathin Al 2 O 3 to increase the exposed facet ratio of (100)/(111), resulting in a faradaic efficiency ratio of C 2 H 4 /CH 4 for overcoated Cu NCs 22 times higher than that for pure Cu NCs. Peak performance of the overcoated catalyst (Cu NCs/ Al 2 O 3 -10C) reaches a C 2 H 4 faradaic efficiency of 60.4 % at a current density of 300 mA cm À2 in 5 M KOH electrolyte, when using a gas diffusion electrode flow cell. Moreover, the Al 2 O 3 overcoating effectively suppresses the dynamic mobility and the aggregation of Cu NCs, which explains the negligible activity loss and selectivity degradations of Cu NCs/Al 2 O 3 -10C shown in stability tests.

Tailoring the Surface and Interface Structures of Copper‐Based Catalysts for Electrochemical Reduction of CO2 to Ethylene and Ethanol

“…[56] Similarly, the relative surface area of Cu(100) was increased by selectively covering the Cu(111) surface of Cu nanocrystals (Cu NCs) with ultrathin Al 2 O 3 layer (Figure 3b), which led to the higher FE ethylene of 60.4%, and the ratio of ethylene/methane for Al 2 O 3 coated Cu NCs was 22 times higher than that for pristine Cu NCs (Figure 3c). [57] More interestingly, Cu-CO 2 catalyst was synthesized by electrodeposition under CO 2 atmosphere, and the ratio of Cu(100) facets to total facet area increased by 70%, compared to that of Cu-HER catalyst electrodeposited in N 2 atmosphere (Figure 3d). As a result, the Cu-CO 2 catalyst achieved the high FE ethylene of 70% (Figure 3e).…”

“…Copyright 2020, American Chemical Society. b,c) Reproduced with permission [57]. Copyright 2021, Wiley-VCH.…”

Recent Advances in Electrochemical, Photochemical, and Photoelectrochemical Reduction of CO2 to C2+ Products

“…[69][70][71][72] The reaction conditions and catalytic performances of Cu-based electrodes for the CO 2 to C 2 H 4 ECRR are summarized in Table 3. [66][67][68][69][70][71][72][73][74][75][76][77][78][79][80] Kim et al converted the morphology of cubic Cu 2 O nanoparticles (NPs) by slow oxidation to synthesize branched CuO NPs that could enhance C 2 H 4 production. [66] Figure 1a shows the synthesis scheme of branched CuO NPs from cubic Cu 2 O NPs.…”