CO2 electroreduction catalyst discovery by high-throughput experimentation: From screening of thin-film material libraries to gas diffusion electrodes

• Applicants: Professorin Dr.-Ing. Corina Andronescu; Professor Dr.-Ing. Alfred Ludwig
• Subject Area: Synthesis and Properties of Functional Materials ; Technical Chemistry
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 506022989

The project aims to accelerate catalyst discovery for CO2 electroreduction (CO2RR) by developing a new methodology for high-throughput testing of new electrocatalyst materials at industrially relevant current densities. We plan to bridge combinatorial co-sputter synthesis of thin-film materials libraries (MLs) with testing of catalyst materials at the gas diffusion electrode (GDE) level by using scanning electrochemical cell microscopy (SECCM) as a high-throughput screening technique to evaluate CO2RR electrocatalyst’s activity at high current densities. In the first part of the project, we aim to understand how SECCM measurements need to be conducted on thin-film electrocatalysts to obtain similar activities as in a GDE. Au and Cu will be used as model catalysts, and sputter techniques will be employed to generate thin-film catalyst layers on flat substrates or 3D-porous PTFE membranes. Improving the adhesion of the metal layer on the PTFE substrate during the sputtering process is targeted. In the second part of the project, we plan to synthesize and characterize MLs, obtained via co-sputtering of elements that strongly (Co, Ni) and weakly (Ag, Au) bind CO and H, aiming to discover new CO2RR to enable the selective synthesis of multicarbon products (C≥2) at industrially relevant current densities. SECCM will be used to evaluate the electrocatalytic activity of the different materials comprised in a ML to identify new catalysts that can reduce CO2 with a minimum current density of 100 mA cm-2, labeled as HITs. The identified HIT compositions will be transferred on GDEs by sputtering on membranes. The CO2RR selectivity of the catalysts embedded in a GDE will be evaluated in a flow-cell electrolyzer coupled with online gas-chromatography and high-liquid performance chromatography. Improving catalyst film stability in a GDE and tuning the catalyst microenvironment on the GDE to modulate selectivity will be realized by co-sputtering of binary and ternary catalysts with PTFE. The correlation of catalyst selectivity with catalyst and electrode structures will be derived, going thus beyond state of the art, where catalyst selectivity is often described without considering the complete system.

• DFG Programme: Research Grants