Tomographic Reconstruction and Analysis of a Silver CO2 Reduction Cathode. Issue 19 (3rd April 2020)

• Record Type: Journal Article
• Authors: McLaughlin, David; Bierling, Markus; Moroni, Riko; Vogl, Christoph; Schmid, Günter; Thiele, Simon
• Is Part Of: Advanced energy materials. Volume 10:Issue 19(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-03
• Subjects: CO2 reduction -- FIB‐SEM -- gas diffusion electrodes -- power‐to‐X technology -- tomography; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202000488
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: Tomographic reconstruction has been well established as a valuable tool in the analysis of polymer electrolyte fuel cell (PEMFC) electrodes. While forays have been made into applying it to polymer electrolyte water electrolyzer (PEMWE) electrodes, CO2 electrolyzer electrodes are still new ground. Here a tomographic analysis of an electrochemical CO2 reduction gas diffusion electrode by means of focused ion beam scanning electron microscope tomography is presented. The reconstruction shows a porosity of 68%. While most of the porosity is on the nanoscale, a broad tail of micropores is observed in the distribution. The spatial distribution of the pores is nonuniform. The large pores are concentrated in the center of the layer in the through‐plane direction. From the reconstruction, an effective diffusivity factor of 0.5 for the catalyst layer is calculated. The Knudsen number of 0.19 obtained from the later shows that the diffusion is mostly in the bulk regime. Flooding of the catalyst layer is likely to decrease the effective diffusivity factor substantially. Abstract : Focused ion beam scanning electron microscope tomography allows for resolution of a nanoporous silver catalyst layer. This allows for the first time the reconstruction of a CO producing CO2 reduction cathode. The tomographic reconstruction allows for the computation of diffusivities. Additionally, energy dispersive X‐ray spectroscopy reveals sign of electrolyte infiltration.