Copper Nanocubes for CO₂ Reduction in Gas Diffusion Electrodes

Abstract

Electroreduction of CO 2 represents a promising solution for addressing the global challenges in energy and sustainability. This reaction is highly sensitive to the surface structure of electrocatalysts and the local electrochemical environment. We have investigated the effect of Cu nanoparticle shape on the electrocatalysis of CO 2 reduction by using gasdiffusion electrodes (GDEs) and flowing alkaline catholytes. Cu nanocubes of ∼70 nm in edge length are synthesized with {100} facets preferentially exposed on the surface. They are demonstrated to possess substantially enhanced catalytic activity and selectivity for CO 2 reduction, compared to Cu nanospheres of similar particle sizes. The electrocatalytic performance was further found to be dependent on the concentration of electrolyte (KOH). The Cu nanocubes reach a Faradaic efficiency of 60% and a partial current density of 144 mA/cm 2 toward ethylene (C 2 H 4 ) production, with the catalytic enhancement being attributable to a combination of surface structure and electrolyte alkalinity effects.

Bi‐Based Metal‐Organic Framework Derived Leafy Bismuth Nanosheets for Carbon Dioxide Electroreduction

“…Hence, after the CAU‐17 precursor activation, the Bi NSs and controlled Bi NPs electrocatalyst with the same loading were tested in 1 m KHCO 3 and KOH electrolyte purging with excess CO 2 gas. As shown in Figure 4 a, although the representative polarization curves of two electrocatalysts are observed to have the same onset potentials at ≈−0.35 and −0.7 V in alkaline electrolyte and neutral pH carbonate solution, which is credible that alkaline electrolyte can not only suppress the competing hydrogen evolution, but also effectively reduce the activation energy barrier, as reported by the relevant works, [ 7a,27c,28 ] Bi NSs electrocatalyst unsurprisingly exhibit higher current densities than that of Bi NPs. Because the electrochemical double‐layer capacitance is nearly sevenfold than that of Bi NPs, which clearly demonstrates that the much larger capacitance of Bi NSs can expose more electrochemically active surface area (Figure S9, Supporting Information).…”

Electrochemical CO2 reduction to high-concentration pure formic acid solutions in an all-solid-state reactor

“…Typically, 500 μL of electrolyte after electrolysis were mixed with 100 μL of D 2 O (Sigma Aldrich, 99.9 at% D) and 0.03 μL dimethyl sulfoxide (Sigma Aldrich, 99.9%) as internal standard. 13 C NMR spectra were acquired using a Bruker AVIII 500 MHz NMR spectrometer at room temperature, to check the purity of the as-prepared HCOOH solution. Typically, 500 µl of electrolyte after electrolysis was mixed with 100 µL of D 2 O (Sigma Aldrich, 99.9 at.% D).…”

“…lectrochemical carbon dioxide reduction reaction (CO 2 RR) is changing the way we produce chemicals and fuels, while helping to mitigate climate change [1][2][3][4][5][6][7][8] . A variety of products ranging from hydrocarbons to oxygenates [9][10][11][12][13][14][15][16][17] and from C 1 to C 3 can be produced from CO 2 RR using different catalytic materials [18][19][20][21][22][23][24] . As the price of renewable electricity continues to decrease, the cost of some CO 2 RR products, particularly those single carbon molecules such as carbon monoxide (CO) and formate, becomes competitive to traditional chemical engineering processes due to their industrially relevant selectivity (>90%) and activity (>100 mA cm −2 ) [25][26][27][28][29][30][31][32][33][34][35][36] .…”

Metal–ligand bond strength determines the fate of organic ligands on the catalyst surface during the electrochemical CO2 reduction reaction

“…17,19,22 Furthermore, colloidal suspensions of these catalysts are appealing as they can be used to deposit CuNCs onto a variety of supports, including gas-diffusion electrodes that can operate at commercially-relevant current densities. 23,24 In some of these studies, the organic ligands functionalising the surface of the NC catalysts were removed prior to catalytic testing using plasma, mild solvent-washing or hydrazine treatments. 17,22,25 However, extreme care is needed to ensure that no undesirable modications of the catalysts are caused by these ligand removal treatments, such as changes of exposed facets or of the copper oxidation state as well as deposition of poorlyunderstood carbonaceous material on the surface.…”