TY - JOUR A1 - Schwarz, I. A1 - Rieck, Arielle A1 - Mehmood, Asad A1 - Bublitz, R. A1 - Bongers, L. A1 - Weuster-Botz, D. A1 - Fellinger, Tim-Patrick T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of −2.4 to −3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however required. Atomically-dispersed M−N−C catalysts show promise, if degradation throughout autoclaving can be omitted. The development of selective and autoclavable catalysts resistant to contamination and electrode design for the complex electrolyte will enable efficient bioelectrocatalytic power-to-X systems based on the introduced BES. KW - Energy Conversion PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594766 DO - https://doi.org/10.1002/celc.202300344 SN - 2196-0216 SP - 1 EP - 10 PB - Wiley VHC-Verlag AN - OPUS4-59476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schwarz, I. A1 - Rieck, Arielle A1 - Fellinger, Tim-Patrick A1 - Weuster-Botz, Dirk T1 - Bio-electrochemical CO2 conversion into organic products using precious-metal free electrocatalysts N2 - For the realization of a sustainable economy, it is of great importance to make use of CO2 for the production of multi-carbon organic chemicals used as feedstock in the chemical industry as well as carbon-neutral fuels (Varela et al. 2019). A promising approach is the electrochemical CO2 reduction followed by microbial conversion of the reduced products. KW - Bio-electrochemical KW - Organic products KW - Electrocatalysts PY - 2024 SP - 1 EP - 2 AN - OPUS4-59572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rieck, Arielle A1 - Schwarz, Irina T1 - Electrochemical CO2 reduction (CO2RR) coupled to gas fermentation with acetogenic bacteria N2 - For the realization of a sustainable energy economy, it is of great importance to develop CO2 -neutral methods producing multi-carbon organic chemicals used as feedstock in the chemical industry as well as carbon-neutral fuels. A promising method to alleviate the greenhouse effect and thereby forming value-added chemicals or syngas as an energy carrier, is through the electrochemical CO2 reduction reaction (CO2RR). In this work, a bioelectrotechnological approach is developed, in which the CO2RR reaction products (CO and H2) are directly fed to bacteria (acetogens), who use them as “reduction equivalents” to further metabolize CO2 to valuable carbon compounds. Therefore, a bio-electrochemical system consisting of a bioreactor coupled to a CO2 electrolysis cell will be established. Currently, scarce catalysts such as Ag and Au are used as for the CO2RR which may hamper the use of decentral CO2 conversion technology for cost reasons. The technological viability of the bacteria-assisted electrolysis depends on the usage of efficient, biocompatible, and selective electrocatalysts prepared from inexpensive precursors. Porous transition metal and nitrogen co-doped carbons (M-N-Cs) have emerged as precious-metal free electrocatalysts for the direct electrochemical reduction of CO2 into CO and are excellent candidates for scale-up and deployment in technological applications. Furthermore, Co/Ni/Zn functioning as the catalytically active sites will be used, as they are expected to depict non-bactericidal properties in contrast to Cu and Ag catalysts. The non-bactericidal property could e.g., allow for application within the hybrid device (bio-electrochemical system), without the need to separate bacteria and cathode catalyst. The MNCs with the most promising electrocatalytic activity and selectivity will be evaluated in abiotic conditions in the hybrid bio-electrochemical reactor system. T2 - DFG Summer School Workshop CY - Hamburg, Germany DA - 01.09.2022 KW - Katalysator KW - CO2 Reduktion KW - Bioelectrochemical CO2 reduction PY - 2022 AN - OPUS4-56618 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rieck, Arielle A1 - Schwarz, Irina T1 - Valorization of CO2 by electrocatalytic reduction coupled to acetogens via multiple electron carriers (Ecat-acetogens) N2 - For the realization of a sustainable energy economy, it is of great importance to develop CO2 -neutral methods producing multi-carbon organic chemicals used as feedstock in the chemical industry as well as carbon-neutral fuels. A promising method to alleviate the greenhouse effect and thereby forming value-added chemicals or syngas as an energy carrier, is through the electrochemical CO2 reduction reaction (CO2RR). In this work, a bioelectrotechnological approach is developed, in which the CO2RR reaction products (CO and H2) are directly fed to bacteria (acetogens), who use them as “reduction equivalents” to further metabolize CO2 to valuable carbon compounds. Therefore, a bio-electrochemical system consisting of a bioreactor coupled to a CO2 electrolysis cell will be established. Currently, scarce catalysts such as Ag and Au are used as for the CO2RR which may hamper the use of decentral CO2 conversion technology for cost reasons. The technological viability of the bacteria-assisted electrolysis depends on the usage of efficient, biocompatible, and selective electrocatalysts prepared from inexpensive precursors. Porous transition metal and nitrogen co-doped carbons (M-N-Cs) have emerged as precious-metal free electrocatalysts for the direct electrochemical reduction of CO2 into CO and are excellent candidates for scale-up and deployment in technological applications. Furthermore, Co/Ni/Zn functioning as the catalytically active sites will be used, as they are expected to depict non-bactericidal properties in contrast to Cu and Ag catalysts. The non-bactericidal property could e.g., allow for application within the hybrid device (bio-electrochemical system), without the need to separate bacteria and cathode catalyst. The MNCs with the most promising electrocatalytic activity and selectivity will be evaluated in abiotic conditions in the hybrid bio-electrochemical reactor system. T2 - DFG Summer School Workshop CY - Hamburg, Germany DA - 01.09.2022 KW - CO2 Reduktion KW - MNC catalyst KW - Clostridium ragsdalei PY - 2022 AN - OPUS4-56619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwarz, I. A1 - Rieck, Arielle A1 - Mehmood, Asad A1 - Bublitz, R. A1 - Bongers, L. A1 - Weuster-Botz, D. A1 - Fellinger, Tim-Patrick T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of 􀀀 2.4 to 􀀀 3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however requ KW - PEM KW - Stirred-Tank Bioreactor KW - Clostridium ragsdalei PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615239 UR - http://www.chemelectrochem.org/ DO - https://doi.org/10.1002/celc.202300344 VL - 11 IS - 6 SP - 1 EP - 9 PB - Chemistry Europe and Wiley-VCH GmbH AN - OPUS4-61523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schwarz, Irina A1 - Rieck, Arielle T1 - Valorization of carbon dioxide by electrocatalytic reduction coupled to acetogens via multiple electron carriers (Ecat-acetogens) N2 - To alleviate CO2 emissions and their impact on climate change, converting carbon dioxide into valuable products such as multi-carbon organic chemicals is of great importance. CO2 can be converted via different pathways such as electrochemical, photo-electrochemical and biological etc. Each approach offers distinct merits but also certain challenges in terms of process efficiency, product selectivity and implementation at scale etc. Therefore, developing coupled CO2 conversion systems, for instance bioelectrochemical reactors, can potentially address some of those challenges.[1] In this work, the focus is on developing cost-efficient, biocompatible, and high activity porous M-N-C catalysts with M = Ni and Co that are atomically dispersed as NiN4 and CoN4 active sites in porous carbon matrix. Ni- and Co-N-Cs are prepared by active-site imprinting approach using Mg as an imprinter.[2][3] Pyrolysis of Mg-N-C is carried out in a salt-melt at high temperatures (≥ 800 oC) and followed by an exchange with Ni or Co at low temperatures. N2-sorption of the materials reveal a micro-mesoporous structure with high surface areas (> 1000 m2 g-1) and a mass-transport enabling pore system. Extended X-ray absorption fine structure (EXAFS) reveal the existence of atomically dispersed single atom active sites with defined active site structure. A variety of Ni-N-Cs and Co-N-Cs were tested for CO2R activity in a rotating disc electrode (RDE) setup, showing high activity and selectivity towards CO2R versus the competing HER. Subsequently, these catalysts were implemented in a home-made bio-electrocatalytical system (BES) consisting of a bioreactor coupled to a CO2 electrolysis cell. Here, CO2 is first electrochemically converted to CO in the electrolysis cell which is then directly fed to bacteria (Clostridium ragsdalei) in bioreactor who further metabolize it to valuable carbon compounds such as acetate. In the BES, partial pressures of CO reached a maximum of 5.7 mbar and that of hydrogen was 2.7 mbar after 30 h. A specific exponential bacterial growth rate of 0.16 h-1 was observed with acetate formation rate of 1.8 mg L-1 h-1 and an acetate concentration of 0.103 g L-1 corresponding to acetate formation rate of 0.73 mmol d-1. As will be discussed in greater details in this talk, we have successfully demonstrated the validity of a coupled bio-electrocatalytical system concept operating with Co- and Ni-N-C catalysts for CO2 conversion. T2 - Joint SPP Conference CY - Jena, Germany DA - 06.11.2024 KW - CO2 Reduktion KW - Bioelectrocatalytical system PY - 2024 AN - OPUS4-61993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schwarz, Irina A1 - Rieck, Arielle T1 - Valorization of carbon dioxide by electrocatalytic reduction coupled to acetogens via multiple electron carriers (Ecat-acetogens) N2 - For the realization of a sustainable energy economy, it is of great importance to develop CO2 -neutral methods producing multi-carbon organic chemicals used as feedstock as well as carbon-neutral fuels by CO2 capture and conversion. In this work, a bio-electrocatalytical system (BES) consisting of a bioreactor coupled to a CO2 electrolysis cell is established. CO2 is first electrochemically converted to CO in electrolysis cell which is then directly fed to bacteria (acetogens) to further metabolize it to valuable carbon compounds such as acetate. The objective of this study is to develop cost-efficient, biocompatible and high activity electrocatalysts that can selectively convert CO2 to CO. Porous nitrogen-doped carbons containing atomically dispersed Ni and Co (Ni or Co-N-Cs) are prepared by active-site imprinting approach. First, synthesis of Mg- or Zn-N-C was carried out through pyrolysis of precursors in a salt melt followed by exchange with Ni or Co. N2-sorption porosimetry of the materials reveal a micro-mesoporous structure with high surface areas (> 1000 m2 g-1) and a mass-transport enabling pore system. Extended X-ray absorption fine structure (EXAFS) reveal the existence of single atom sites with no formation of nanoparticles. A variety of Ni-N-Cs and Co-N-Cs were tested for CO2R activity in a rotating disc electrode (RDE) setup, showing high activity (Tafel slopes range from 77 – 130 mV/decade) and selectivity towards CO2R versus the competing HER. Before operation in the BES, first tests were performed in a single cell. Significantly increased current was detected in the CO2R test in CO2-saturated electrolyte vs. in N2 -saturated electrolyte indirectly proving formation of carbon monoxide (CO). Transfer of the electrolysis cell operation into the BES proved to be successful. For biotic operation, the BES was inoculated with Clostridium ragsdalei. Partial pressures pCO reached a maximum of 5.7 mbar and pH2 was 2.7 mbar after 30h. The reduction of partial pressures is interpreted as the consumption of the gases by C.ragsdalei. We report a specific exponential growth rate of 0.16 h-1, acetate formation rate of 1.8 mg L-1 h-1 and an acetate concetration of 0.103 g L-1 corresponding to acetate formation rate of 0.73 mmol d-1.In this work we successfully demonstrated an integrated bio-electrocatalytic system (BES) to convert CO2 into value-added chemicals. The usage of a Co- and Ni-N-Cs as the reduction catalyst within the BES allowed production of CO and H2 with relative selectivity for CO resulting in the growth of Clostridium ragsdalei and acetate production. T2 - Joint SPP Conference CY - Jena, Germany DA - 06.11.2023 KW - Bioelectrocatalytical system PY - 2023 AN - OPUS4-61995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schwarz, Irina A1 - Rieck, Arielle T1 - Valorization of carbon dioxide by electrocatalytic reduction coupled to acetogens via multiple electron carriers (Ecat-acetogens) N2 - To alleviate CO2 emissions and their impact on climate change, converting carbon dioxide into valuable products such as multi-carbon organic chemicals is of great importance. CO2 can be converted via different pathways such as electrochemical, photo-electrochemical and biological etc. Each approach offers distinct merits but also certain challenges in terms of process efficiency, product selectivity and implementation at scale etc. Therefore, developing coupled CO2 conversion systems, for instance bioelectrochemical reactors, can potentially address some of those challenges.[1] In this work, the focus is on developing cost-efficient, biocompatible, and high activity porous M-N-C catalysts with M = Ni and Co that are atomically dispersed as NiN4 and CoN4 active sites in porous carbon matrix. Ni- and Co-N-Cs are prepared by active-site imprinting approach using Mg as an imprinter.[2][3] Pyrolysis of Mg-N-C is carried out in a salt-melt at high temperatures (≥ 800 oC) and followed by an exchange with Ni or Co at low temperatures. N2-sorption of the materials reveal a micro-mesoporous structure with high surface areas (> 1000 m2 g-1) and a mass-transport enabling pore system. Extended X-ray absorption fine structure (EXAFS) reveal the existence of atomically dispersed single atom active sites with defined active site structure. A variety of Ni-N-Cs and Co-N-Cs were tested for CO2R activity in a rotating disc electrode (RDE) setup, showing high activity and selectivity towards CO2R versus the competing HER. Subsequently, these catalysts were implemented in a home-made bio-electrocatalytical system (BES) consisting of a bioreactor coupled to a CO2 electrolysis cell. Here, CO2 is first electrochemically converted to CO in the electrolysis cell which is then directly fed to bacteria (Clostridium ragsdalei) in bioreactor who further metabolize it to valuable carbon compounds such as acetate. In the BES, partial pressures of CO reached a maximum of 5.7 mbar and that of hydrogen was 2.7 mbar after 30 h. A specific exponential bacterial growth rate of 0.16 h-1 was observed with acetate formation rate of 1.8 mg L-1 h-1 and an acetate concentration of 0.103 g L-1 corresponding to acetate formation rate of 0.73 mmol d-1. As will be discussed in greater details in this talk, we have successfully demonstrated the validity of a coupled bio-electrocatalytical system concept operating with Co- and Ni-N-C catalysts for CO2 conversion. T2 - eBiotech Workshop Week + Status Seminar CY - Jena, Germany DA - 19.03.2023 KW - Bioelectrocatalytical system PY - 2023 AN - OPUS4-61997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Rieck, Arielle A1 - Low, Jian Liang A1 - Dietzmann, Simon A1 - Radnik, Jörg A1 - Teimouri, Zahra A1 - Higgins, Drew A1 - Hodoroaba, Vasile-Dan A1 - Mehmood, Asad A1 - Fellinger, Tim-Patrick T1 - Understanding the Activity Trade-Off between Tetrapyrrolic Fe-NCs and Co-NCs in the Alkaline Oxygen Reduction Reaction N2 - A water-free ionothermal synthesis of porous magnesium-imprinted nitrogen-doped carbon (Mg–NC) materials is introduced to prepare a platform material to investigate electrocatalytic structure-performance relations. Atomically dispersed Co- and Fe-NCs isomorphic to the pristine Mg-NCs are prepared by ion-exchange reactions. The current Mg-templating strategy enables relatively high pyrolysis product yields of up to 50 wt% and resultant Fe-NC and Co-NC catalysts contain high and comparable active metal loading of up to 2.52 wt% Fe and 2.29 wt% Co, respectively. A combination of X-ray spectroscopies with DFT studies reveals a tetrapyrrolic structure of the coordination sites, originating from a pyrolytic magnesium template ion reaction within the ionothermal synthesis. Two sets of highly active isomorphic tetrapyrrolic Fe-NCs and Co-NCs are utilized to understand the differences in intrinsic electrocatalytic performance of Co-NCs and Fe-NCs towards the alkaline oxygen reduction reaction (ORR). Despite their superior valence electronic properties to facilitate the initial outer-sphere electron transfer to O2, Co-NCs show significantly lower performance than Fe-NC with comparable loading. Although the generally discussed weaker binding of peroxide intermediates to CoN4 sites compared to FeN4 sites is evident, experimental and theoretical investigation reveal that it is the underlying peroxide oxidation activity that suppresses the oxygen reduction activity of M-NCs. The high peroxide oxidation activity of Co-NCs explains their reduced alkaline ORR relative to Fe-NCs, shedding light on the understated significance of controlling peroxide chemistry for the optimizing cathodic performance. KW - Magnesium Imprinting KW - Tetrapyrrolic Sites KW - Metal- and nitrogen-doped carbon (M-N-C) KW - Oxygen Reduction Reaction (ORR) KW - Nitrogen doped Carbon PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651487 DO - https://doi.org/10.26434/chemrxiv-2025-s59s5 SP - 1 EP - 24 AN - OPUS4-65148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leonhardt, Robert A1 - Böttcher, Nils A1 - Dayani, Shahabeddin A1 - Rieck, Arielle A1 - Markötter, Henning A1 - Schmidt, Anita A1 - Kowal, Julia A1 - Tichter, Tim A1 - Krug von Nidda, Jonas T1 - Exploring the electrochemical and physical stability of lithium-ion cells exposed to liquid nitrogen N2 - The transport and storage of lithium-ion (Li-ion) batteries — damaged or in an undefined state — is a major safety concern for regulatory institutions, transportation companies, and manufacturers. Since (electro)chemical reactivity is exponentially temperature-dependent, cooling such batteries is an obvious measure for increasing their safety. The present study explores the effect of cryogenic freezing on the electrochemical and physical stability of Li-ion cells. For this purpose, three different types of cells were repeatedly exposed to liquid nitrogen (LN2). Before and after each cooling cycle, electrical and electrochemical measurements were conducted to assess the impact of the individual freezing steps. While the electrochemical behavior of the cells did not change significantly upon exposure to LN2 , it became apparent that a non-negligible number of cells suffered from physical changes (swelling) and functional failures. The latter defect was found to be caused by the current interrupt device of the cylindrical cells. This safety mechanism is triggered by the overpressure of expanding nitrogen which enters the cells at cryogenic temperatures. This study underlines that the widely accepted reversibility of LN2 -cooling on a material scale does not allow for a direct extrapolation toward the physical integrity of full cells. Since nitrogen enters the cell at cryogenic temperatures and expands upon rethermalization, it can cause an internal overpressure. This can, in turn, lead to mechanical damage to the cell. Consequently, a more appropriate temperature condition — less extreme than direct LN2 exposure — needs to be found KW - Lithium-ion battery KW - LN2 cooling KW - Battery characterization PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599248 DO - https://doi.org/10.1016/j.est.2024.111650 VL - 89 SP - 1 EP - 7 PB - Elsevier B.V. AN - OPUS4-59924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -