Controlling the Surface Oxidation of Cu Nanowires Improves Their Catalytic Selectivity and Stability toward C₂₊ Products in CO₂ Reduction

Abstract

Copper nanostructures are promising catalysts for the electrochemical reduction of CO 2 because of their unique ability to produce alarge proportion of multi-carbon products. Despite great progress,t he selectivity and stability of such catalysts still need to be substantially improved. Here,w e demonstrate that controlling the surface oxidation of Cu nanowires (CuNWs) can greatly improve their C 2+ selectivity and stability.S pecifically,w ea chieve af aradaic efficiency as high as 57.7 and 52.0 %f or ethylene when the CuNWs are oxidized by the O 2 from air and aqueous H 2 O 2 ,r espectively, and both of them showh ydrogen selectivity below1 2%.T he high yields of C 2+ products can be mainly attributed to the increase in surface roughness and the generation of defects and cavities during the electrochemical reduction of the oxide layer. Our results also indicate that the formation of arelatively thick, smooth oxide sheath can improve the catalytic stability by mitigating the fragmentation issue.

Design principles of tandem cascade photoelectrochemical devices

“…map onto experiments performed in near-neutral pH in CO2-saturated water; these current densities are conservative estimates of typical 1-sun short circuit current densities of GaInP/GaAs tandem solar cells. 48 For both catalysts, we will neglect the competing hydrogen evolution reaction (which can have a faradaic efficiency (FE) as low as 10% on Cu) such that all current is used for CO2 reduction; 49 assumptions regarding the faradaic efficiencies to the different C-containing products 8 will be discussed below. We also assume that the CO produced at the Au catalyst will be available for further conversion at the Cu; prior experimental work has shown this diffusion or convectivemediated pathway can be very efficient.…”

Facile design of oxide‐derived Cu nanosheet electrocatalyst for CO2 reduction reaction

“…42 Although the surface morphologies of CuO NSs and Cu-30 are comparable, the ECSA of Cu-30 is twice as large as that of CuO NSs due to the unique partial oxidation state of Cu + surface and the abundant defect sites provided by the nanodomains. 21 Accordingly, the enlarged nano-domains on Cu-30 were obtained after 1 h electrolysis (Figure S7) and achieved the highest roughness factor of 93 based on defining pc-Cu as one. 43 It is notable that the dissociation of CO 2 molecules is one of the rate determining stages, also the energy barrier of CO 2 decomposition (the absorbed dissociative CO 2 !…”

“…For instance, a thin CuO x sheath on the surface of OD-Cu nanowires was formed by slowly oxidized in air atmosphere and reached up to 78% of FE for C 2+ products. 21 In addition, by using the O 2 plasma treated Cu nanocubes, the selectivity of C 2 H 4 and the current density in CO 2 RR were enhanced compared to that under Ar plasma treatment. 22 Besides the oxidation state, the role of surface roughening on the OD-Cu was also examined to enrich the catalytic active sites.…”

“…[23][24][25][26][27] The roughened surface possesses abundant interfaces, grain boundaries, and low coordinated sites, which are generally regarded as the active sites to trap the key intermediate *CO and initiate the dimerization step. 21 However, the existing post-treatments on the pristine Cu such as plasma irradiation, 10 air-oxidation, 28 and electropolishing 29 are still difficult to well-controllably synthesize OD-Cu. A facile method to efficiently fabricate the OD-Cu nanocatalysts is highly desired.…”