@article{galinsky_sendi_bowers_li_2016, title={CaMn1-xBxO3-delta (B = Al, V, Fe, Co, and Ni) perovskite based oxygen carriers for chemical looping with oxygen uncoupling (CLOU)}, volume={174}, ISSN={["1872-9118"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963788767&partnerID=MN8TOARS}, DOI={10.1016/j.apenergy.2016.04.046}, abstractNote={Operated under a cyclic redox mode in the presence of an oxygen carrier, the chemical looping with oxygen uncoupling (CLOU) process has the potential to effectively combust solid carbonaceous fuels while capturing CO2. The overall process is enabled by an oxygen carrier that is capable of reversibly exchanging its lattice oxygen (O2−) with gaseous oxygen (O2) under varying external oxygen partial pressures (PO2). As such, further improvements of the CLOU process relies largely on the identification of oxygen carriers with higher activity, better recyclability, and improved resistance toward physical degradation. This article investigates dopant effects on CLOU properties of oxygen carriers with a CaMnO3 parent structure. Various B-site compatible metal cations including Fe, Ni, Co, V, and Al are incorporated into the perovskite. While CaMnO3 suffers from stability issues resulting from irreversible transitions to spinel (CaMn2O4) and Ruddlesden–Popper (Ca2MnO4) structures under typical CLOU redox conditions, a number of B-site doped perovskites exhibited promising phase stability and redox activity. Of the oxygen carriers investigated, Fe-doped CaMnO3 exhibits the most promising CLOU properties while showing high compatibility with the CaMnO3 parent structure. In terms of redox performance, CaMn1−xFexO3−δ exhibit notable redox activity at temperatures as low as 600 °C. No deactivation was observed over 100 redox cycles. The doped perovskite structure was also significantly more stable than undoped CaMnO3, showing no signs of decomposition at 1200 °C. When operated under identical conditions, the Fe-doped oxygen carrier is observed to achieve significantly higher conversion of Pittsburgh #8 coal char compared to undoped CaMnO3 oxygen carrier, when operated at 850 °C.}, journal={APPLIED ENERGY}, author={Galinsky, Nathan and Sendi, Marwan and Bowers, Lindsay and Li, Fanxing}, year={2016}, month={Jul}, pages={80–87} }
 @article{mishra_galinsky_he_santiso_li_2016, title={Perovskite-structured AMn(x)B(1-x)O(3) (A = Ca or Ba; B = Fe or Ni) redox catalysts for partial oxidation of methane}, volume={6}, ISSN={["2044-4761"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84975156629&partnerID=MN8TOARS}, DOI={10.1039/c5cy02186c}, abstractNote={High oxygen carrying capacity, lack of loosely bound lattice oxygen, and preferential surface segregation of Ba make BaMnxB1−xO3 (B = Ni or Fe) based redox catalysts suitable for chemical looping reforming of methane with high syngas yield and coke resistance.}, number={12}, journal={CATALYSIS SCIENCE & TECHNOLOGY}, author={Mishra, Amit and Galinsky, Nathan and He, Feng and Santiso, Erik E. and Li, Fanxing}, year={2016}, pages={4535–4544} }
 @article{galinsky_mishra_zhang_li_2015, title={Ca(1-x)A(x)MnO(3) (A = Sr and Ba) perovskite based oxygen carriers for chemical looping with oxygen uncoupling (CLOU)}, volume={157}, ISSN={["1872-9118"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85007035468&partnerID=MN8TOARS}, DOI={10.1016/j.apenergy.2015.04.020}, abstractNote={Operated under a cyclic redox mode with an oxygen carrier, the chemical looping with oxygen uncoupling (CLOU) process offers the potential to effectively combust solid fuels while capturing CO2. Development of oxygen carriers capable of reversibly exchanging their active lattice oxygen (O2−) with gaseous oxygen (O2) under varying external oxygen partial pressure (PO2) is of key importance to CLOU process performance. This article investigates the effect of A-site dopants on CaMnO3 based oxygen carriers for CLOU. Both Sr and Ba are explored as potential dopants at various concentrations. Phase segregations are observed with the addition of Ba dopant even at relatively low concentrations (5% A-site doping). In contrast, stable solid solutions are formed with Sr dopant at a wide range of doping level. While CaMnO3 perovskite suffers from irreversible change into Ruddlesden–Popper (Ca2MnO4) and spinel (CaMn2O4) phases under cyclic redox conditions, Sr doping is found to effectively stabilize the perovskite structure. In-situ XRD studies indicate that the Sr doped CaMnO3 maintains a stable orthorhombic perovskite structure under an inert environment (tested up to 1200 °C). The same oxygen carrier sample exhibited high recyclability over 100 redox cycles at 850 °C. Besides being highly recyclable, Sr doped CaMnO3 is found to be capable of releasing its lattice oxygen at a temperature significantly lower than that for CaMnO3, rendering it a potentially effective oxygen carrier for solid fuel combustion and carbon dioxide capture.}, journal={APPLIED ENERGY}, author={Galinsky, Nathan and Mishra, Amit and Zhang, Jia and Li, Fanxing}, year={2015}, month={Nov}, pages={358–367} }
 @article{galinsky_shafiefarhood_chen_neal_li_2015, title={Effect of support on redox stability of iron oxide for chemical looping conversion of methane}, volume={164}, ISSN={["1873-3883"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84908004028&partnerID=MN8TOARS}, DOI={10.1016/j.apcatb.2014.09.023}, abstractNote={The chemical looping processes utilize lattice oxygen in oxygen carriers to convert carbonaceous fuels in a cyclic redox mode while capturing CO2. Typical oxygen carriers are composed of a primary oxide for active lattice oxygen storage and a ceramic support for enhanced redox stability and activity. Among the various primary oxides reported to date, iron oxide represents a promising option due to its low cost and natural abundance. The current work investigates the effect of support on the cyclic redox performance of iron oxides as well as the underlying mechanisms. Three ceramic supports with varying physical and chemical properties, i.e. perovskite-structured Ca0.8Sr0.2Ti0.8Ni0.2O3, fluorite-structured CeO2, and spinel-structured MgAl2O4, are investigated. The results indicate that the redox properties of the oxygen carrier, e.g. activity and long-term stability, are significantly affected by support and iron oxide interactions. The perovskite supported oxygen carrier exhibits high activity and stability compared to oxygen carriers with ceria support, which deactivate by as much as 75% within 10 redox cycles. The high stability of perovskite supported oxygen carrier is attributable to its high mixed ionic–electronic conductivity. Deactivation of ceria supported samples results from solid-state migration of iron cations and subsequent enrichment on the oxygen carrier surface. This leads to agglomeration and lowered lattice oxygen accessibility. Activity of MgAl2O4 supported oxygen carrier is found to increase during redox cycles in methane. The activity increase is a consequence of surface area increase caused by filamentous carbon formation and oxygen carrier fragmentation. While higher redox activity is desired for chemical looping processes, physical degradation of oxygen carriers can be detrimental.}, journal={APPLIED CATALYSIS B-ENVIRONMENTAL}, author={Galinsky, Nathan L. and Shafiefarhood, Arya and Chen, Yanguang and Neal, Luke and Li, Fanxing}, year={2015}, month={Mar}, pages={371–379} }
 @article{shafiefarhood_galinsky_huang_chen_li_2014, title={Fe2O3@LaxSr1-xFeO3 Core- Shell Redox Catalyst for Methane Partial Oxidation}, volume={6}, ISSN={["1867-3899"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84896870404&partnerID=MN8TOARS}, DOI={10.1002/cctc.201301104}, abstractNote={Abstract}, number={3}, journal={CHEMCATCHEM}, author={Shafiefarhood, Arya and Galinsky, Nathan and Huang, Yan and Chen, Yanguang and Li, Fanxing}, year={2014}, month={Mar}, pages={790–799} }
 @article{chen_galinsky_wang_li_2014, title={Investigation of perovskite supported composite oxides, for chemical looping conversion of syngas}, volume={134}, ISSN={["1873-7153"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84903579385&partnerID=MN8TOARS}, DOI={10.1016/j.fuel.2014.06.017}, abstractNote={In typical chemical looping processes, a transition metal oxide based oxygen carrier is used to indirectly convert carbonaceous fuels into concentrated CO2 and carbon free products through cyclic redox reactions. Among the various oxygen carrier candidates, iron oxide represents a promising option due to its abundance, low cost, and unique thermodynamic properties. A key challenge for ferrite based oxygen carriers resides in their low redox activity. In the current study, composite iron oxides with three types of mixed ionic–electronic conductive (MIEC) supports, i.e. lanthanum strontium ferrite (Sr-substituted lanthanum ferrite or LSF), barium cerium ferrite (Ce-substituted barium ferrite, BCF) and calcium titanate ferrite (Fe-substituted calcium titanate, CTF), are synthesized using solid state reaction (SSR) and sol–gel methods. Among the three MIEC materials, CTF support is found to possess superior structural stability. MIEC supported oxygen carriers are found to be significantly more active than a reference, yttrium-stabilized zirconia (YSZ) supported oxygen carrier. Higher support conductivity and smaller iron oxide precursor sizes generally lead to enhanced oxygen carrier activity. In contrast, surface area of the oxygen carrier is weakly correlated with its redox activity. CTF, although less conductive compared to BCF and LSF, is stable and sufficiently effective in shuttling active O2− and electrons for syngas oxidation and iron oxide regeneration. Therefore, CTF supported ferrites can potentially be a cost-effective oxygen carrier candidate for chemical looping processes. Further improvements in redox activity of the oxygen carriers can be achieved through iron oxide particle size reduction and support conductivity enhancement.}, journal={FUEL}, author={Chen, Yanguang and Galinsky, Nathan and Wang, Ziren and Li, Fanxing}, year={2014}, month={Oct}, pages={521–530} }
 @article{he_galinsky_li_2013, title={Chemical looping gasification of solid fuels using bimetallic oxygen carrier particles - Feasibility assessment and process simulations}, volume={38}, ISSN={["1879-3487"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84879093997&partnerID=MN8TOARS}, DOI={10.1016/j.ijhydene.2013.04.054}, abstractNote={The chemical looping gasification (CLG) process utilizes an iron-based oxygen carrier to convert carbonaceous fuels into hydrogen and electricity while capturing CO2. Although the process has the potential to be efficient and environmentally friendly, the activity of the iron-based oxygen carrier is relatively low, especially for solid fuel conversion. In the present study, we propose to incorporate a secondary oxygen carrying metal oxide, i.e. CuO, to the iron-based oxygen carrier. Using the “oxygen-uncoupling” characteristics of CuO, gaseous oxygen is released at a high temperature to promote the conversion of both Fe2O3 and coal. Experiments carried out using a Thermal-Gravimetric Analyzer (TGA) indicate that a bimetallic oxygen carrier consisting of a small amount (5% by weight) of CuO is more effective for coal char conversion when compared to oxygen carrier without copper addition. ASPEN Plus® simulations and mathematical modeling of the process indicate that the incorporation of a small amount of copper leads to increased hydrogen yield and process efficiency.}, number={19}, journal={INTERNATIONAL JOURNAL OF HYDROGEN ENERGY}, author={He, Feng and Galinsky, Nathan and Li, Fanxing}, year={2013}, month={Jun}, pages={7839–7854} }
 @article{galinsky_huang_shafiefarhood_li_2013, title={Iron Oxide with Facilitated O2- Transport for Facile Fuel Oxidation and CO2 Capture in a Chemical Looping Scheme}, volume={1}, ISSN={["2168-0485"]}, DOI={10.1021/sc300177j}, abstractNote={The chemical looping strategy offers a potentially viable option for efficient carbonaceous fuel conversion with a reduced carbon footprint. In the chemical looping process, an oxygen carrier is reduced and oxidized in a cyclic manner to convert a carbonaceous fuel into separate streams of concentrated carbon dioxide and carbon-free products such as electricity and/or hydrogen. The reactivity and chemical and physical stability of the oxygen carrier are of pivotal importance to chemical looping processes. A typical oxygen carrier is composed of a multi-valence transition metal oxide supported on an “inert” support. Although the support does not get reduced or oxidized at any significant extent, numerous studies have indicated that certain supports such as TiO2 and Al2O3 can improve oxygen carrier stability and/or reactivity. This study reports the use of mixed ionic–electronic conductive support in iron-based oxygen carriers. By incorporating a perovskite-based mixed conductive support such as lanthanum s...}, number={3}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Galinsky, Nathan L. and Huang, Yan and Shafiefarhood, Arya and Li, Fanxing}, year={2013}, month={Mar}, pages={364–373} }