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Projects / Programmes source: ARIS

Thermocatalytic and combined thermo-photocatalytic CH4 reforming with CO2 over nanoshaped Ni/CeO2 and PM-Ni/CeO2-TiO2 materials

Research activity

Code Science Field Subfield
2.02.04  Engineering sciences and technologies  Chemical engineering  Catalysis and reaction engineering 

Code Science Field
T350  Technological sciences  Chemical technology and engineering 

Code Science Field
2.04  Engineering and Technology  Chemical engineering  
Keywords
syngas, methane activation, CO2 valorization, structurally defined nanomaterials, photocatalysis
Evaluation (rules)
source: COBISS
Researchers (8)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  08387  PhD Iztok Arčon  Physics  Researcher  2019 - 2022  766 
2.  17283  Špela Božič    Technical associate  2019 - 2020  38 
3.  28557  PhD Petar Djinović  Chemical engineering  Head  2019 - 2022  246 
4.  52002  PhD Kristijan Lorber  Chemical engineering  Junior researcher  2019 - 2022  29 
5.  25023  PhD Matjaž Mazaj  Chemistry  Researcher  2021 - 2022  286 
6.  11874  PhD Albin Pintar  Chemical engineering  Researcher  2019 - 2022  854 
7.  38311  PhD Janvit Teržan  Chemical engineering  Junior researcher  2019 - 2020  75 
8.  32927  PhD Gregor Žerjav  Chemical engineering  Researcher  2019 - 2020  194 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0104  National Institute of Chemistry  Ljubljana  5051592000  21,316 
2.  1540  University of Nova Gorica  Nova Gorica  5920884000  14,206 
Abstract
Indirect conversion of natural gas into added value chemicals and fuels via syngas is, and likely will remain the industrially prevailing route. The methane-CO2 reforming reaction (DRM) is an attractive pathway for production of CO-rich syngas. The absence of a traditional oxidant in the feed (H2O or O2) substantially increases the thermodynamic driving force for carbon formation on the catalyst’s surface and deactivation. Low-temperature activation of methane is a major scientific and technological objective. Due to inertness of both reactants and endothermic nature of DRM reaction, high energy input and temperatures (above 700 °C) are required for achieving high methane conversions. Highly active catalysts that are capable of activating methane and CO2 at low temperatures (300-600 °C) based on supported transition metals are required. Recent research indicates that such a candidate is Ni/CeO2, which can activate methane already at room temperature. Nanoshaped Ni/CeO2 catalysts will be the cornerstone of this research project. Running the catalytic reaction at low temperatures enables survival of the initial nanomaterial’s morphology and most reactive surface sites, which is not possible at high temperatures due to sintering. This enables experimental work with morphologically defined nanomaterials and acquisition of structure-activity data, i.e. active site identification. First part of this research project will be focused on improving our understanding of active site requirement for low temperature (300-600 °C) methane and CO2 activation over structurally defined nanoshaped Ni/CeO2 catalysts in the form of polyhedra, cubes and rods. The role of nickel cluster size, metal support interface, redox and acid-base properties will be systematically investigated.   The second part of the project will be focused on a combined thermo-photocatalytic activation of methane and CO2 over newly developed composite catalysts. The Ni/CeO2 catalyst by itself does not fulfill the requirement for photocatalytic CO2 reduction to CO, as the conduction band position of CeO2 is approximately 0.2-0.5 eV too negative compared to CO2/CO redox potential. The visible light absorption capability and appropriate band positions will be provided by reduced TiO2-x in the Ni/CeO2-TiO2-x composite catalyst. The appropriate band positions of reduced TiO2-x are prerequisites for both half reactions to proceed photocatalytically: CO2 reduction to CO with excited electrons in the conduction band and CH4 oxidation to CO with holes in the valence band. In addition, conduction band of CeO2 is approximately 0.4 eV lower, which makes the migration of photo-generated electrons from the CB of TiO2-x to CeO2-x thermodynamically possible. Charge separation will prolong their lifetime and additionally create nucleophilic (basic) centers on CeO2-x which assist the CO2 activation. In order to maximize the light-matter interaction and consequently its efficient utilization for the DRM reaction, the active metal component will be tuned with the addition of an appropriate plasmonic metal: Rh and Cu to form PM-Ni clusters dispersed over CeO2-x-TiO2-x support. Since point of zero charge for CeO2 and TiO2 are different, Rh and Cu can be selectively deposited over either CeO2 or TiO2. As a result, spatial control over Ni and Cu/Rh location is possible (case A: Ni on CeO2, Cu or Rh over TiO2 or case B: Ni and Cu or Rh over CeO2, TiO2 remains bare). This way, the main pathway of photocatalytic action should be revealed: Cu and Rh act as plasmonic antenna (case B) or indirectly via charge carrier participation mediated by TiO2 and CeO2 (case A). In this project, use of in-situ and operando analytical techniques (DRIFTS, XAS, NAP-XPS, UV-Vis, etc.) will be employed, enabling unsurpassed insight and novelty in the analysis of the working state of the catalyst and as such improving the understanding of the low-temperature thermally, as well as photo catalytically
Significance for science
Methane is an abundant hydrocarbon that is extensively used as fuel and for production of chemicals via syngas (mixture of CO and H2). Carbon dioxide is the most important greenhouse gas whose elevated concentrations drastically influence the quality of our lives through climate changes. As a result, an economically viable pathway for their simultaneous valorization via the methane dry reforming reaction is of highest importance for the energy, environmental and scientific sectors. The reaction can be performed at high temperatures, which was confirmed in the past, also through financial contribution of ARRS (project number Z2-5463). A tremendous impact on catalytic and materials science and also chemical industry would be made if the reaction temperature could be decreased to 300-500°C from the existing 700-1000°C. As a result, waste heat streams could be used to drive the reaction and the overall efficiency of the chemical conversion will be improved. In addition, if (visible) light could be used to drive the catalytic chemical conversion of methane and CO2, this would represent a deviation from the current fossil fuel dependency. The realization of these ideas requires a considerable scientific effort with the efficient material (catalyst) and reactor (chemical engineering approach) design. As a result, work planned in this research proposal is aimed to tackle currently very relevant issues: low temperature methane and CO2 activation over supported transition metal catalysts driven by heat and light-matter interaction. Since relatively low reaction temperatures will be used, catalysts with defined active site geometry can be investigated thus obtaining precise structure activity relationships. Also, several in-situ and operando techniques can be applied, revealing the actual working state of the catalyst. This will bring unprecedented insight into the reaction mechanism and chemistry occurring over the surface of the supported metal/oxide catalysts during the chemical turnover. We strongly believe this could result in new, cutting edge scientific findings that can be applied to a broader spectrum of materials outside of catalysis, e.g. sensors.
Significance for the country
Methane is an abundant hydrocarbon that is extensively used as fuel and for production of chemicals via syngas (mixture of CO and H2). Carbon dioxide is the most important greenhouse gas whose elevated concentrations drastically influence the quality of our lives through climate changes. As a result, an economically viable pathway for their simultaneous valorization via the methane dry reforming reaction is of highest importance for the energy, environmental and scientific sectors. The reaction can be performed at high temperatures, which was confirmed in the past, also through financial contribution of ARRS (project number Z2-5463). A tremendous impact on catalytic and materials science and also chemical industry would be made if the reaction temperature could be decreased to 300-500°C from the existing 700-1000°C. As a result, waste heat streams could be used to drive the reaction and the overall efficiency of the chemical conversion will be improved. In addition, if (visible) light could be used to drive the catalytic chemical conversion of methane and CO2, this would represent a deviation from the current fossil fuel dependency. The realization of these ideas requires a considerable scientific effort with the efficient material (catalyst) and reactor (chemical engineering approach) design. As a result, work planned in this research proposal is aimed to tackle currently very relevant issues: low temperature methane and CO2 activation over supported transition metal catalysts driven by heat and light-matter interaction. Since relatively low reaction temperatures will be used, catalysts with defined active site geometry can be investigated thus obtaining precise structure activity relationships. Also, several in-situ and operando techniques can be applied, revealing the actual working state of the catalyst. This will bring unprecedented insight into the reaction mechanism and chemistry occurring over the surface of the supported metal/oxide catalysts during the chemical turnover. We strongly believe this could result in new, cutting edge scientific findings that can be applied to a broader spectrum of materials outside of catalysis, e.g. sensors.
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