Selective CO2 Reduction to CO and Alcohols without Platinum or Noble Group Electrodes

Projektbeschreibung

Bessere elektrochemische Umwandlung von CO2: kostengünstig, hochselektiv und nachhaltig

Kohlenstoffhaltige Verbindungen sind das Ausgangsmaterial für zahlreiche Chemikalien und Polymere, darunter Kunststoffe, Gummi und Reinigungsmittel. Umweltfreundlichere Alternativen stellen ein wichtiges Ziel der chemischen Industrie dar, da die meisten Produkte aus fossilen Rohstoffen gewonnen werden. Die elektrochemische Umwandlung von CO2 ist vielversprechend, steht jedoch vor Herausforderungen. Dazu zählen die Notwendigkeit, Anoden auf Iridiumbasis zu verwenden, um die Versauerung von CO2-Elektrolyseuren zu vermeiden, und die Schwierigkeit, eine hohe Selektivität bei der Herstellung von Alkoholen mit hoher Energiedichte zu erreichen. Im Rahmen des ERC-finanzierten Projekts RECALLCO2 wird versucht, diese Hindernisse zu beseitigen. Sie werden ein neuartiges elektrochemisches Zelldesign, molekulare Katalysatorarchitekturen, die die derzeitigen Beschränkungen überwinden, und die Kopplung mit Metallelektroden anstelle von Kohlenstoffelektroden entwickeln.

Ziel

The electrochemical conversion of CO2 to carbon-based feedstocks represents one of few technological routes capable of replacing fossil fuel derivatives. Despite substantial advancements, however, major challenges impair CO2 electrolysis from matching its promise. Critically, steady acidification of CO2 electrolyzers during operation currently necessitates the use of iridium-based anodes. This is unacceptable from a cost and resource availability perspective. More fundamentally, while CO2 reduction to CO, formate and ethylene has become highly selective, the production of high-energy density alcohols with high selectivity has been elusive. To overcome these barriers, new scientific approaches are needed.

RECALLCO2 will resolve iridium dependencies and non-selective alcohol production in CO2 electrolysis through a combination of novel electrochemical cell design and the development of molecular catalytic architectures which break existing fundamental limitations. On the system design front, I will micro manipulate reagent, ionic and water fluxes to inhibit nickel corrosion pathways which presently necessitate iridium anodes. This will be the first-ever intrinsically stable CO2 electrolyzer capable of using nickel anodes.

A second pillar is the conceptualization that strong electronic-coupling of metal complexes to metal electrodes can eliminate redox-controlled reaction pathways on molecular catalysts. This counters decades of work using carbon electrodes as supports. Coupling with a metal electrode will delink electron transfers from a molecular catalysts oxidation states, and fundamentally change catalytic behaviour that currently restricts reactions to 2 electrons. Thus, CO2 reduction products such as methanol (6 electrons) and ethanol (12 electrons) will become viable. Utilizing this counterintuitive approach, I will push alcohol synthesis well beyond state-of-the-art selectivity and reaction rates, giving renewed promise for producing these compounds.