Steering Hydrocarbon Selectivity in CO₂ Electroreduction over Soft-Landed CuO_x Nanoparticle-Functionalized Gas Diffusion Electrodes

Abstract

The use of physical vapor deposition methods in the fabrication of catalyst layers holds promise for enhancing the efficiency of future carbon capture and utilization processes such as the CO2 reduction reaction (CO2RR). Following that line of research, we report in this work the application of a sputter gas aggregation source (SGAS) and a multiple ion cluster source type apparatus, for the controlled synthesis of CuO x nanoparticles (NPs) atop gas diffusion electrodes. By varying the mass loading, we achieve control over the balance between methanation and multicarbon formation in a gas-fed CO2 electrolyzer and obtain peak CH4 partial current densities of −143 mA cm–2 (mass activity of 7.2 kA/g) with a Faradaic efficiency (FE) of 48% and multicarbon partial current densities of −231 mA cm–2 at 76% FE (FEC2H4 = 56%). Using atomic force microscopy, electron microscopy, and quasi in situ X-ray photoelectron spectroscopy, we trace back the divergence in hydrocarbon selectivity to differences in NP film morphology and rule out the influence of both the NP size (3–15 nm, >20 μg cm–2) and in situ oxidation state. We show that the combination of the O2 flow rate to the aggregation zone during NP growth and deposition time, which affect the NP production rate and mass loading, respectively, gives rise to the formation of either densely packed CuO x NPs or rough three-dimensional networks made from CuO x NP building blocks, which in turn affects the governing CO2RR mechanism. This study highlights the potential held by SGAS-generated NP films for future CO2RR catalyst layer optimization and upscaling, where the NPs’ tunable properties, homogeneity, and the complete absence of organic capping agents may prove invaluable.

Efficient Electromethanation from CO2 on Monodisperse Cu-Based Catalysts

“…In comparison to the recently published electromethanation of CO 2 (Figure a), Cu–DCD 40 demonstrates high selectivity (FE) and activity (partial current density) of electromethanation. ,− To evaluate the stability of the as-prepared catalyst, “pause electrolysis” to suppress the carbonate issue is adopted in this work . The pause electrolysis is shown in Figure b.…”

Advances in Functionalized Nanomaterial‐incorporated Biosensing Platforms for Detecting Cancer Biomarkers during Biopsies

“…[11] Modification is an effective approach toward improving the performance of electrodes given that it changes the physical and chemical properties to provide for better bioelectrocatalyst attachment and electron transfer. Although novel electrodebased platforms, such as gas diffusion electrodes, [41] carbonbased foams, [42] and electrospun carbon nanofibers, [43] have been developed to meet the requirements of various applications, many need to be improved before practical use. In addition, thin coatings of silver (Ag), [44,45] and silicon dioxide (SiO 2 ) [9] effectively improve the interactive interface and reduce the activation energy threshold of electron transfer.…”

Advances in cutting‐edge electrode engineering toward CO2 electrolysis at high current density and selectivity: A mini‐review

“…This enabled higher partial current densities toward value‐added C 2+ products, and also shifted their selectivity. In situ oxidation for forming CuO x NP films with various mass loadings onto the GDLs as electrodes for CO 2 RR was reported by Deams et al [ 35 ] A sputter gas aggregation source together with a multiple ion cluster source‐type apparatus was employed. This demonstrated the distinct advantage of simultaneously control of the thickness/areal density, as well as the oxidation state of the as‐formed CuO x film layer during electrode preparation.…”

“…Furthermore, other advanced strategies have also been explored for the fabrication of CO 2 RR electrodes; however, they are still at an initial state, such as 3D printing, and in situ oxidation. [34,35] For example, by applying 3D printing technique, Wicks et al [34] reported the fabrication of a porous fluoropolymer as the base GDL, which was further coated with a conformal Cu layer and served as the electrode for CO 2 RR. The influence of several controllable structural parameters on the efficiency and selectivity of CO 2 RR was also investigated.…”