Enhancement of CO₂RR product formation on Cu-ZnO-based electrodes by varying ink formulation and post-treatment methods

Abstract

Numerous catalysts have been reported with enhanced performance, e.g. longer lifetime and improved selectivity, for the electrochemical CO2 reduction reaction (CO2RR). Respectively little is, however, known about the influence of the electrode structuring and pre-treatment on this reaction for catalytic layers. Thus, we herein report on the modification of the catalyst environment of a Cu-ZnO-carbon black catalyst by variation of the ink composition and subsequent electrode treatment before performing CO2RR. We furthermore provide insight into the impact of solvents used for the ink preparation, ionomer and additives like pore forming agents as well as post treatment steps in terms of pressing and sintering of electrodes on the CO2RR performance. Although using the same catalyst for all electrodes, remarkable differences in hydrophobicity, surface morphology and electrochemical performance with respect to stability and product distribution are observed. Our study reveals the critical role of the catalytic layer assembly aside using proper catalysts. We furthermore show that the parasitic hydrogen formation and flooding behavior can be lowered and C2+ product formation enhanced when operated in optimized gas diffusion electrodes (GDE).

Navigating through Complexity: Optimizing Cathodes for Organic Electrohydrogenation through Coherent Workflows

“…Furthermore, the binder can modulate the wettability as well as the ionic conductivity of the catalyst layer. Well‐known versatile binders include various ionomers, methylcellulose derivatives, polyvinyl difluoride (PVDF), and polytetrafluoroethylene (PTFE) [29] . A B/C ratio of around 0.1 can be chosen as a starting point and then analyzed, for instance via analytical centrifugation.…”

“…Well-known versatile binders include various ionomers, methylcellulose derivatives, polyvinyl difluoride (PVDF), and polytetrafluoroethylene (PTFE). [29] A B/C ratio of around 0.1 can be chosen as a starting point and then analyzed, for instance via analytical centrifugation. Depending on the solvent, some binders will stabilize the dispersion while others will lead to agglomeration/precipitation and thus increased sedimentation.…”

Recent Progress on Electrode Design for Efficient Electrochemical Valorisation of CO2, O2, and N2

“…[33,51] In addition, some post-treatment, such as hot pressing, can be employed to enhance the surface hydrophobicity of the electrode, enabling higher CO 2 reduction activity along with multi-carbon product formation. [52] Nevertheless, electrodes prepared from powdery catalysts usually suffered from several intrinsic drawbacks, refraining them from achieving higher performances in electrolysers. Firstly, these catalyst-coated electrodes usually feature a stacked catalyst layer, where only the outermost catalysts can participate in the reaction, while those buried inside are inaccessible to both gas and liquid reactants, leading to low catalyst utilisation efficiency.…”

“…Meanwhile, various coating technologies, such as spray coating and blade coating, can be applied to the fabrication process, which provides manufacturing flexibility [33, 51] . In addition, some post‐treatment, such as hot pressing, can be employed to enhance the surface hydrophobicity of the electrode, enabling higher CO 2 reduction activity along with multi‐carbon product formation [52] …”

Forschungstransfer: Elektrochemische CO2‐Reduktion

“…Beispiele hierfür sind das Quantifizieren von CO 2 aus Anoden-und Kathodengasströmen, um die Produktzusammensetzung zu bestimmen, das Verstehen von Crossover-Effekten und die Bereitstellung von Informationen zur Elektrodenstruktur wie Adhäsion, Porosität und Hydrophobizität. [7][8][9][10][11][12] Um dieses Verständnisdefizit zu überwinden, sind gemeinschaftlich kohärente Arbeitsabläufe zu entwickeln -um Ursache-Wirkungs-Kor-relationen aufzuklären und diese auf physikalische Parameter zurückzuführen. Diese sollten für jeden Elektrokatalysator, für die Herstellung von Aktivmaterialien und Elektroden sowie für Tests entwickelt werden.…”