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The direct conversion of synthesis gas could open up economically viable routes for the efficient production of ethanol. RhMn/SiO2 represents one of the most active systems reported thus far. Potential improvements were reported by added dopants, i.e., Ir, Ti, and Li. Yet, combining these elements leads to contradicting results, owing to the complexity of the interactions in a multi-promoted system. This complexity is often encountered in heterogeneous catalysis. We report a systematic data-driven approach for the assessment of complex multi-promoter interactions based on a combination of design-of-experiment, high-throughput experimentation, statistical analysis, and mechanistic assessment. We illustrate this approach for the system RhMn/SiO2 promoted with Ir, Li, and Ti. Using this approach, we investigate the impact of promoters’ interactions on a mechanistic level. Our analysis depicts the means to learn hidden correlations in the performance data and, additionally, high performance for ethanol yield for the RhMnIr/SiO2 catalyst. The method presented outlines an efficient way to also elucidate co-promoter interactions in other complex environments.

With the increasing production of renewable energy and concomitant depletion of fossil resources, the demand for efficient water splitting electrocatalysts continues to grow. Iridium (Ir) and iridium oxides (IrOx) are currently the most promising candidates for an efficient oxygen evolution reaction (OER) in acidic medium, which remains the bottleneck in water electrolysis. Yet, the extremely high costs for Ir hamper a widespread production of hydrogen (H2) on an industrial scale. Herein, the authors report a concept for the synthesis of electrode coatings with template-controlled mesoporosity surface-modified with highly active Ir species. The improved utilization of noble metal species relies on the synthesis of soft-templated metal oxide supports and a subsequent shape-conformal deposition of Ir species via atomic layer deposition (ALD) at two different reaction temperatures. The study reveals that a minimum Ir content in the mesoporous titania-based support is mandatory to provide a sufficient electrical bulk conductivity. After ALD, a significantly enhanced OER activity results in dependency of the ALD cycle number and temperature. The most active developed electrocatalyst film achieves an outstanding mass-specific activity of 2622 mA mgIr–1 at 1.60 VRHE in a rotating-disc electrode (RDE) setup at 25 °C using 0.5 m H2SO4 as a supporting electrolyte.

CO2 Fischer–Tropsch synthesis (CO2–FTS) is a promising technology enabling conversion of CO2 into valuable chemical feedstocks via hydrogenation. Iron–based CO2–FTS catalysts are known for their high activities and selectivities towards the formation of higher hydrocarbons. Importantly, iron carbides are the presumed active phase strongly associated with the formation of higher hydrocarbons. Yet, many factors such as reaction temperature, atmosphere, and pressure can lead to complex transformations between different oxide and/or carbide phases, which, in turn, alter selectivity. Thus, understanding the mechanism and kinetics of carbide formation remains challenging. We propose model–type iron oxide films of controlled nanostructure and phase composition as model materials to study carbide formation in syngas atmospheres. In the present work, different iron oxide precursor films with controlled phase composition (hematite, ferrihydrite, maghemite, maghemite/magnetite) and ordered mesoporosity are synthesized using the evaporation–induced self–assembly (EISA) approach. The model materials are then exposed to a controlled atmosphere of CO/H2 at 300 °C. Physicochemical analysis of the treated materials indicates that all oxides convert into carbides with a core–shell structure. The structure appears to consist of crystalline carbide cores surrounded by a partially oxidized carbide shell of low crystallinity. Larger crystallites in the original iron oxide result in larger carbide cores. The presented simple route for the synthesis and analysis of soft–templated iron carbide films will enable the elucidation of the dynamics of the oxide to carbide transformation in future work.

As-prepared materials tested for a catalytic reaction are usually only precatalysts that become active and/or selective under specific conditions. During this initial formation phase, catalysts can undergo a change in their structure, morphology, chemical state, or even composition. This dynamic behavior has a vital impact on reactivity, and we identified that this initial formation phase is also critical for Rh in the catalytic conversion of synthesis gas to oxygenates and ethanol in particular. The syngas-to-ethanol reaction (StE) is a promising alternative route to ethanol from fossil and nonfossil carbon resources. Despite heavy research efforts, rates and selectivities still need to be improved for industrial operations. For this reason, structure–function relationships at industrially relevant reaction conditions must be clarified. Although some in situ and operando studies have been reported, a pressure gap still exists between experimental and process-relevant high-pressure conditions. To overcome this pressure gap and investigate the dynamic behavior of Rh-based catalysts under reaction conditions, we applied a generic method for formation phase studies at high partial pressures of synthesis gas where standard operando methods are inapplicable. Combining integral and local characterization methods before and after a long-term catalytic test of a RhFeOx/SiO2 catalyst (>140 h on stream) allowed us to ascribe a drastic decrease in ethanol formation to a structural change from an unalloyed RhFeOx to an alloyed RhFe/FeOx nanostructure. Our investigation provides an explanation for the great variation of reported catalytic results of RhFe catalysts and their nanostructures in synthesis gas conversion. The structure–function relationship we identified finally provides the opportunity for improved catalyst design strategies: stabilizing the Rh–FeOx interface by preventing RhFe nanoalloy formation. As one example, we report a RhFeOx catalyst on a high surface area Mn2O3 support which decreases the Fe mobility and reducibility through the formation of a (Fe,Mn)Ox mixed surface oxide. Stabilizing the Rh–FeOx interface finally led to stable ethanol selectivity, and the formation of RhFe nanoalloy structures was not observed.

Die Katalyse ist ein sehr komplexes und interdisziplinäres wissenschaftliches Gebiet, das die effiziente Herstellung einer Vielzahl von Produkten für verschiedene Branchen und in unterschiedlichen Produktionsgrößen ermöglicht. Somit ist die Katalyse eine der Schlüsseltechnologien zur Bewältigung wesentlicher Herausforderungen wie einer nachhaltigen Energieversorgung oder des Klimawandels. Das Datenmanagement in der Katalyse ist derzeit überwiegend auf institutioneller oder Arbeitsgruppenebene organisiert und basiert auf lokalen Konventionen. Übergreifende Repositorien und Standards, wie Daten inklusive Metadaten gespeichert werden sollen, existieren nur in rudimentärer Form. Um den höchstmöglichen Mehrwert aus der Katalyseforschung zu generieren, ist ein grundlegender Wandel in der Katalyseforschung und den katalyseverwandten Wissenschaften wie Chemieingenieurwesen und Verfahrenstechnik erforderlich. Die verschiedenen Disziplinen der Katalyse im Hinblick auf das Datenmanagement zusammenzuführen, ist die zentrale Herausforderung. Aus all diesen Notwendigkeiten heraus wurde im Rahmen der Initiative zur Nationalen Forschungsdateninfrastruktur (NFDI) das NFDI4Cat-Konsortium gegründet. Als eines von derzeit neun geförderten Konsortien konzentriert sich NFDI4Cat auf die Wissenschaften rund um die Katalyse. Dieser Artikel beschreibt die Motivation der Gründungsmitglieder für dieses im Oktober 2020 gestartete Konsortium und wie die Ziele in Bezug auf die Fachcommunity, die technische Infrastruktur und insbesondere das Forschungsdatenmanagement erreicht werden sollen. Darüber hinaus eröffnet die dynamische Entwicklung moderner Technologien zur Erfassung, Bereitstellung und zur Analyse großer Datenmengen neue Möglichkeiten für wissenschaftlichen Fortschritt in den Einzeldisziplinen und insbesondere an deren Nahtstellen.