Project

Discipline

Metal plating; Carbon dioxide; Electrochemistry; Electrocatalysis

Lead
Kohlendioxid (CO2) ist eines der anthropogenen Treibhausgase, die massgeblich für die globale Klimaerwärmung verantwortlich sind und vor allem durch die Verbrennung fossiler Brennstoffe wie Kohle, Öl und Erdgas in die Erdatmosphäre unvermindert emittiert werden. Dringend gefragt sind nicht nur Strategien zur Vermeidung von CO2-Emissionen durch alternative, klimafreundlichere Energiequellen, sondern auch Konzepte zur Umwandlung des bereits in der Atmosphäre vorhandenen, schädlichen Kohlendioxids in wertvollere Stoffe (z.B. in Brennstoffe für Brennstoffzellentechnologie oder in Ausgangsstoffe für die industrielle Synthese von Stoffen/Polymere). Die physikochemischen Grundlagen dieses sogenannten CO2 to value-Konzepts sind Thema dieses Projektes.
Lay summary
Inhalt und Ziel des Forschungsprojekts CO2 soll mit Hilfe von überschüssigem, elektrischem Strom in nutzbare Stoffe (z.B. Alkohole, Ameisensäure, Ethylen etc.) umgewandelt werden. Für diese elektrochemische Konversion benötigt man spezielle Katalysatoren, um die Reduktion des sehr stabilen Kohlendioxids signifikant zu beschleunigen. Im Fokus dieses Projektes stehen neuartige Metallschaumkatalysatoren auf Kupferbasis, die sich neben ihrer hohen katalytischen Aktivität durch eine extrem grosse innere Oberfläche auszeichnen. Diese hochporösen Metallschaumkatalysatoren sollen durch eine Additiv-gesteuerte Metallabscheidung auf geeigneten technischen Substraten hergestellt werden. Ziel des Projektes ist die Entwicklung dieser Kupferkatalysatoren für grosstechnische CO2-Elektrolyseure.        Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts Erklärtes dieses Projektes ist es, einen wissenschaftlichen und technischen Beitrag zur Lösung des globalen CO2-Problems zu leisten idurch die Entwicklung eines energieeffizienten Prozesses zur elektrochemischen CO2-Konversion. 1. Mai 2017

Direct link to Lay Summary

Last update: 01.05.2017

Self-organised

Self-organised

Title	Year

Number	Title	Start	Funding scheme

The proposed project entitled "CO2 to value: Electroconversion of CO2 on Electrodeposited Metal Foam Catalysts" aims to develop new catalysts concepts for the electrochemical conversion of CO2 into products of higher value (C-C coupled C2-4 products and formate) which have a high potential to be implemented into future industrial CO2 technology applications. New concepts of catalyst design will make use of an additive-assisted electroplating process which is highly versatile in terms of controlling the catalyst morphology on various length scales that are relevant for the creation of catalytically active sites (nm-scale) and the reactant/intermediate/product mass transport (µm-scale). The resulting product distribution of the electrochemical CO2 conversion is believed to be a result of the concerted effects taking place on these nm- and µm-length scales. The Cu- and Sn-based catalysts to be designed are highly porous metal foams whose composition and porosity can carefully be controlled by the experimental parameters. A key point in the catalyst design is the formation of well-defined oxide-phases on these metal foams during or after their electrodeposition. The most active catalysts are believed to be composites of these metal foam materials and their corresponding (surface) oxide-phases. The latter are typically consumed/degraded under conditions of the CO2 conversion. In this respect these materials are not catalysts in the classical sense which leave the catalytic cycle unchanged. Therefore we intend to develop so-called operando spectroscopies which are particularly sensitive to the presence of oxidic species (operando Raman approach). Their presence will be studied under reactive conditions as a function of the applied potential and the electrolyte composition. The key scientific working hypothesis to be proven is that the oxide phases are still present (and active for the CO2 conversion) even at electrode potentials where these are thermodynamically instable (kinetic stabilization). Such operando spectroscopies should further be used to develop strategies how these catalytically active oxide phases are either recovered (e.g. by anodization) or conserved under operando conditions (e.g. by diffusion-limited metal deposition superimposed on the CO2 conversion). These experimental approaches are meant to deepen our mechanistic understanding of the CO2 conversion process here particularly focusing on the potential-dependent chemical state of the highly porous catalyst. A further important goal of this project is to translate the functional metal foams that are selective towards certain CO2 reduction products onto 2D Cu mesh and/or 3D skeleton supports (excluded are any carbon supports). They allow for a more detailed study of the reactant/intermediate/product transport through the catalyst material. An important factor determining both the catalyst activity and the selectivity towards certain products is the mean residence time of the reactants/intermediates/products inside the catalyst. Kinetic data of the electrochemical CO2 conversion should therefore be collected under controlled mass transfer conditions (convection/diffusion) through the catalyst.