Dataset Information

Uncovering the reaction mechanism behind CoO as active phase for CO₂ hydrogenation.

ABSTRACT: Transforming carbon dioxide into valuable chemicals and fuels, is a promising tool for environmental and industrial purposes. Here, we present catalysts comprising of cobalt (oxide) nanoparticles stabilized on various support oxides for hydrocarbon production from carbon dioxide. We demonstrate that the activity and selectivity can be tuned by selection of the support oxide and cobalt oxidation state. Modulated excitation (ME) diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) reveals that cobalt oxide catalysts follows the hydrogen-assisted pathway, whereas metallic cobalt catalysts mainly follows the direct dissociation pathway. Contrary to the commonly considered metallic active phase of cobalt-based catalysts, cobalt oxide on titania support is the most active catalyst in this study and produces 11% C₂₊ hydrocarbons. The C₂₊ selectivity increases to 39% (yielding 104 mmol h^-1 g_cat^-1 C₂₊ hydrocarbons) upon co-feeding CO and CO₂ at a ratio of 1:2 at 250 °C and 20 bar, thus outperforming the majority of typical cobalt-based catalysts.

SUBMITTER: Have ICT

PROVIDER: S-EPMC8760247 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundReplacing fossil fuels as energy carrier requires alternatives that combine sustainable production, high volumetric energy density, easy and fast refueling for mobile applications, and preferably low risk of hazard. Molecular hydrogen (H2) has been considered as promising alternative; however, practical application is struggling because of the low volumetric energy density and the explosion hazard when stored in large amounts. One way to overcome these limitations is the transient conversion of H2 into other chemicals with increased volumetric energy density and lower risk hazard, for example so-called liquid organic hydrogen carriers such as formic acid/formate that is obtained by hydrogenation of CO2. Many homogenous and heterogenous chemical catalysts have been described in the past years, however, often requiring high pressures and temperatures. Recently, the first biocatalyst for this reaction has been described opening the route to a biotechnological alternative for this conversion.ResultsThe hydrogen-dependent CO2 reductase (HDCR) is a highly active biocatalyst for storing H2 in the form of formic acid/formate by reversibly catalyzing the hydrogenation of CO2. We report the identification, isolation, and characterization of the first thermostable HDCR operating at temperatures up to 70 °C. The enzyme was isolated from the thermophilic acetogenic bacterium Thermoanaerobacter kivui and displays exceptionally high activities in both reaction directions, substantially exceeding known chemical catalysts. CO2 hydrogenation is catalyzed at mild conditions with a turnover frequency of 9,556,000 h-1 (specific activity of 900 µmol formate min-1 mg-1) and the reverse reaction, H2 + CO2 release from formate, is catalyzed with a turnover frequency of 9,892,000 h-1 (930 µmol H2 min-1 mg-1). The HDCR of T. kivui consists of a [FeFe] hydrogenase subunit putatively coupled to a tungsten-dependent CO2 reductase/formate dehydrogenase subunit by an array of iron-sulfur clusters.ConclusionsThe discovery of the first thermostable HDCR provides a promising biological alternative for a chemically challenging reaction and might serve as model for the better understanding of catalysts able to efficiently reduce CO2. The catalytic activity for reversible CO2 hydrogenation of this enzyme is the highest activity known for bio- and chemical catalysts and requiring only ambient temperatures and pressures. The thermostability provides more flexibility regarding the process parameters for a biotechnological application.

Dataset Information

Uncovering the reaction mechanism behind CoO as active phase for CO₂ hydrogenation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Uncovering the reaction mechanism behind CoO as active phase for CO2 hydrogenation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Uncovering the reaction mechanism behind CoO as active phase for CO₂ hydrogenation.