@article{vogt-lowell_chacko_yang_carsten_liu_housley_li_2024, title={Molten-Salt-Mediated Chemical Looping Oxidative Dehydrogenation of Ethane with <i>In-Situ</i> Carbon Capture and Utilization}, volume={11}, ISSN={["1864-564X"]}, url={https://doi.org/10.1002/cssc.202401473}, DOI={10.1002/cssc.202401473}, abstractNote={Abstract The molten‐salt‐mediated oxidative dehydrogenation (MM‐ODH) of ethane (C 2 H 6 ) via a chemical looping scheme represents an effective carbon capture and utilization (CCU) method for the valorization of ethane‐rich shale gas and concurrent mitigation of carbon dioxide (CO 2 ) emissions. Here, stepwise experimentation with Li 2 CO 3 ‐Na 2 CO 3 ‐K 2 CO 3 (LNK) ternary salts (i) assessed how each component of the LNK mixture impacted ethane MM‐ODH performance and (ii) explored physicochemical and thermodynamic mechanisms behind melt‐induced changes to ethylene (C 2 H 4 ) and carbon monoxide (CO) yields. Of fifteen screened LNK compositions, nine exhibited ethylene yields greater than 50 % at 800 °C while maintaining C 2 H 4 selectivities of 85 % or higher. LNK salts rich in Li 2 CO 3 content yielded more ethylene and CO on average than their counterparts, and net CO 2 capture per cycle reached a maximum of ~75 %. Extended MM‐ODH cycling also demonstrated long‐term stability of a high‐performing LNK medium. Density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations suggested that the molten salt does not directly activate C 2 H 6 . Meanwhile, an empirical model informed by experimental data and reaction thermodynamics adequately predicted overall MM‐ODH performance from LNK composition and provided insights into the system′s primary drivers.}, journal={CHEMSUSCHEM}, author={Vogt-Lowell, Kyle and Chacko, Dennis and Yang, Kunran and Carsten, Jace and Liu, Junchen and Housley, Matthew and Li, Fanxing}, year={2024}, month={Nov} }
 @article{brody_lis_ortiz_kosari_vogt-lowell_portillo_schomaecker_wachs_li_2024, title={Synergistic Cooperation of Dual-Phase Redox Catalysts in Chemical Looping Oxidative Coupling of Methane}, volume={8}, ISSN={["2155-5435"]}, url={https://doi.org/10.1021/acscatal.4c03001}, DOI={10.1021/acscatal.4c03001}, abstractNote={Chemical looping oxidative coupling of methane (CL-OCM) presents a promising route for light olefin production, offering a simpler alternative to conventional methane steam reforming approaches. The selection of the redox catalyst used in CL-OCM is critical since it must achieve high C2+ yields (>25%) while maintaining longevity in harsh reaction environments. We present a comprehensive performance evaluation and characterization of an understudied, yet highly effective redox catalyst capable of achieving and maintaining a C2+ yield of 26.8% at 840 °C. Through extensive ex situ and in situ analyses, including X-ray diffraction, near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), and Raman spectroscopy, we have characterized the catalyst and identified two distinct bulk, crystalline phases: cubic LixMg6–xMnO8 and orthorhombic Mg3–xMnx(BO3)O2. Calcination at 1200 °C, as opposed to a typical calcination temperature of 900 °C, increased the orthoborate oxide phase to ∼45 wt % while reducing the BET surface area by 65%. By investigating performance differences between these catalysts in their "sintered" and "presintered" states, we have unveiled surprising cooperative effects between the two phases. Experiments with physical mixing of these two phases (granular stacking and mortar mixing) revealed that observed differences in CL-OCM efficacy cannot be solely due to sintering-induced loss of surface area but are also the result of synergistic, dual-phase interactions that enhance overall C2+ yield. H2-temperature programmed reduction measurements and ex situ XPS analysis demonstrate that the sintered catalyst has a lower average Mn-oxidation state, enabling more selective lattice oxygen release and limiting overoxidation to COx species. Additionally, NAP-XPS and in situ Raman characterization suggest that boron–oxygen coordinated sites (BOx) may also play a role in improving selectivity. Leveraging insights from our phase mixture CL-OCM performance tests, steady-state experiments with cofed O2, and corroborative in situ characterizations, we propose that the synergistic interplay between LixMg6–xMnO8 and Mg3–xMnx(BO3)O2 may be the result of facile oxygen release from the more redox-active LixMg6–xMnO8 phase combined with Li+ migration to the orthoborate oxide phase.}, journal={ACS CATALYSIS}, author={Brody, Leo and Lis, Bar Mosevitzky and Ortiz, Abigail Perez and Kosari, Mohammadreza and Vogt-Lowell, Kyle and Portillo, Sam and Schomaecker, Reinhard and Wachs, Israel E. and Li, Fanxing}, year={2024}, month={Aug} }
 @article{liu_yusuf_jackson_martin_chacko_vogt-lowell_neal_li_2022, title={Redox oxide@molten salt as a generalized catalyst design strategy for oxidative dehydrogenation of ethane via selective hydrogen combustion}, volume={646}, ISSN={["1873-3875"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85138532754&partnerID=MN8TOARS}, DOI={10.1016/j.apcata.2022.118869}, abstractNote={The current study demonstrates a redox oxide @ molten salt core-shell architecture as a generalized redox catalyst design strategy for chemical looping – oxidative dehydrogenation of ethane. 17 combinations of redox active oxides and molten salts were prepared, evaluated, and characterized. X-ray diffraction indicates that the redox oxides and molten salts are fully compatible, forming separate and stable phases. X-ray photoelectron spectroscopy demonstrates that the molten salts aggregate at the redox oxide surface, forming a core-shell structure to block the non-selective sites responsible for COx formation. Up to ∼74 % single-pass olefin yields were achieved using the proposed redox catalyst design strategy. Statistical analyses of the performance data indicate the potential to achieve up to 86.7 % single-pass yield by simply optimizing the operating conditions using the redox catalysts reported in this study. Meanwhile, the generalizability of the catalyst design strategy offers exciting opportunities to further optimize the composition and performance of the redox catalysts for ethane ODH under a chemical looping scheme with significantly reduced energy consumption and CO2 emissions.}, journal={APPLIED CATALYSIS A-GENERAL}, author={Liu, Junchen and Yusuf, Seif and Jackson, Daniel and Martin, William and Chacko, Dennis and Vogt-Lowell, Kyle and Neal, Luke and Li, Fanxing}, year={2022}, month={Sep} }