@article{krzywanski_ashraf_czakiert_sosnowski_grabowska_zylka_kulakowska_skrobek_mistal_gao_2022, title={CO2 Capture by Virgin Ivy Plants Growing Up on the External Covers of Houses as a Rapid Complementary Route to Achieve Global GHG Reduction Targets}, volume={15}, ISSN={["1996-1073"]}, DOI={10.3390/en15051683}, abstractNote={Global CO2 concentration level in the air is unprecedently high and should be rapidly and significantly reduced to avoid a global climate catastrophe. The work indicates the possibility of quickly lowering the impact of changes that have already happened and those we know will happen, especially in terms of the CO2 emitted and stored in the atmosphere, by implanting a virgin ivy plant on the available area of walls and roofs of the houses. The proposed concept of reducing CO2 from the atmosphere is one of the technologies with significant potential for implementation entirely and successfully. For the first time, we showed that the proposed concept allows over 3.5 billion tons of CO2 to be captured annually directly from the atmosphere, which makes even up 6.9% of global greenhouse gas emissions. The value constitutes enough high CO2 reduction to consider the concept as one of the applicable technologies allowing to decelerate global warming. Additional advantages of the presented concept are its global nature, it allows for the reduction of CO2 from all emission sources, regardless of its type and location on earth, and the fact that it will simultaneously lower the air temperature, contribute to oxygen production, and reduce dust in the environment.}, number={5}, journal={ENERGIES}, author={Krzywanski, Jaroslaw and Ashraf, Waqar Muhammad and Czakiert, Tomasz and Sosnowski, Marcin and Grabowska, Karolina and Zylka, Anna and Kulakowska, Anna and Skrobek, Dorian and Mistal, Sandra and Gao, Yunfei}, year={2022}, month={Mar} }
 @article{wang_gao_krzystowczyk_iftikhar_dou_cai_wang_ruan_ye_li_2022, title={High-throughput oxygen chemical potential engineering of perovskite oxides for chemical looping applications}, volume={2}, ISSN={["1754-5706"]}, url={https://doi.org/10.1039/D1EE02889H}, DOI={10.1039/d1ee02889h}, abstractNote={Chemical looping (CL) represents a versatile, emerging strategy for sustainable chemical and energy conversion. Designing metal oxide oxygen carriers with suitable redox properties remains one of the most critical challenges...}, number={4}, journal={ENERGY & ENVIRONMENTAL SCIENCE}, publisher={Royal Society of Chemistry (RSC)}, author={Wang, Xijun and Gao, Yunfei and Krzystowczyk, Emily and Iftikhar, Sherafghan and Dou, Jian and Cai, Runxia and Wang, Haiying and Ruan, Chongyan and Ye, Sheng and Li, Fanxing}, year={2022}, month={Feb} }
 @article{iftikhar_martin_gao_yu_wang_wu_li_2022, title={LaNixFe1−xO3 as flexible oxygen or carbon carriers for tunable syngas production and CO2 utilization}, volume={416}, ISSN={0920-5861}, url={http://dx.doi.org/10.1016/j.cattod.2022.07.022}, DOI={10.1016/j.cattod.2022.07.022}, abstractNote={The current study reports LaFe1−xNixO3−δ redox catalysts as flexible oxygen or carbon carriers for CO2 utilization and tunable production of syngas at relatively low temperatures (∼700 °C), in the context of a hybrid redox process. Specifically, perovskite-structured LaFe1−xNixO3−δ with seven different compositions (x = 0.4–1) were prepared and investigated. Cyclic experiments under alternating methane and CO2 flows indicated that all the samples exhibited favorable reactive performance: CH4 and CO2 conversions varied between 85% and 98% and 70–88%, respectively. While H2/CO ratio from Fe-rich redox catalysts was ~2.3:1 in the methane conversion step, Ni-rich catalysts produced a concentrated (~ 93.7 vol%) hydrogen stream via methane cracking. The flexibility of LaFe1−xNixO3−δ to produce syngas (or hydrogen) with tunable compositions was found to be governed by the iron/nickel (Fe/Ni) ratio. Redox catalysts with higher Fe contents act as a lattice oxygen carrier via chemical looping partial oxidation (CLPOx) of methane whereas those with higher Ni contents function as a carbon carrier via chemical looping methane cracking (CLMC) scheme. XRD analysis and temperature-programmed reactions revealed that both types of catalysts involve the formation of La2O3 and Ni0 /Ni-Fe phases under the methane environment. The ability to re-incorporate La2O3 and Ni/Fe into a perovskite structure gives rise to oxygen-carrying capacity whereas stable Ni0 or Ni/Fe phases would catalyze methane cracking without lattice oxygen exchange in the reaction cycles. Temperature programmed oxidation and Raman spectroscopy indicated the presence of graphitic and amorphous carbon species, which were effectively gasified by CO2 to produce concentrated CO. Stability tests over LaFe0.5Ni0.5O3 and LaNiO3 revealed that the redox performance was stable over a span of 50 cycles.}, journal={Catalysis Today}, publisher={Elsevier BV}, author={Iftikhar, Sherafghan and Martin, William and Gao, Yunfei and Yu, Xinbin and Wang, Iwei and Wu, Zili and Li, Fanxing}, year={2022}, month={Jul} }
 @article{krzywanski_czakiert_zylka_nowak_sosnowski_grabowska_skrobek_sztekler_kulakowska_ashraf_et al._2022, title={Modelling of SO2 and NOx Emissions from Coal and Biomass Combustion in Air-Firing, Oxyfuel, iG-CLC, and CLOU Conditions by Fuzzy Logic Approach}, volume={15}, ISSN={["1996-1073"]}, DOI={10.3390/en15218095}, abstractNote={Chemical looping combustion (CLC) is one of the most advanced technologies allowing for the reduction in CO2 emissions during the combustion of solid fuels. The modified method combines chemical looping with oxygen uncoupling (CLOU) and in situ gasification chemical looping combustion (iG-CLC). As a result, an innovative hybrid chemical looping combustion came into existence, making the above two technologies complementary. Since the complexity of the CLC is still not sufficiently recognized, the study of this process is of a practical significance. The paper describes the experiences in the modelling of complex geometry CLC equipment. The experimental facility consists of two reactors: an air reactor and a fuel reactor. The paper introduces the fuzzy logic (FL) method as an artificial intelligence (AI) approach for the prediction of SO2 and NOx (i.e., NO + NO2) emissions from coal and biomass combustion carried out in air-firing; oxyfuel; iG-CLC; and CLOU conditions. The developed model has been successfully validated on a 5 kWth research unit called the dual fluidized bed chemical looping combustion of solid fuels (DFB-CLC-SF).}, number={21}, journal={ENERGIES}, author={Krzywanski, Jaroslaw and Czakiert, Tomasz and Zylka, Anna and Nowak, Wojciech and Sosnowski, Marcin and Grabowska, Karolina and Skrobek, Dorian and Sztekler, Karol and Kulakowska, Anna and Ashraf, Waqar Muhammad and et al.}, year={2022}, month={Nov} }
 @article{wang_yang_ji_gao_li_zhang_wei_2022, title={Reduction kinetics of SrFeO3-delta/CaO center dot MnO nanocomposite as effective oxygen carrier for chemical looping partial oxidation of methane}, volume={11}, ISSN={["2095-0187"]}, DOI={10.1007/s11705-022-2188-5}, journal={FRONTIERS OF CHEMICAL SCIENCE AND ENGINEERING}, author={Wang, Xinhe and Yang, Liuqing and Ji, Xiaolin and Gao, Yunfei and Li, Fanxing and Zhang, Junshe and Wei, Jinjia}, year={2022}, month={Nov} }
 @article{iftikhar_martin_wang_liu_gao_li_2022, title={Ru-promoted perovskites as effective redox catalysts for CO2 splitting and methane partial oxidation in a cyclic redox scheme}, volume={11}, ISSN={["2040-3372"]}, url={https://doi.org/10.1039/D2NR04437D}, DOI={10.1039/d2nr04437d}, abstractNote={The current study reports AxA'1-xByB'1-yO3-δ perovskite redox catalysts (RCs) for CO2-splitting and methane partial oxidation (POx) in a cyclic redox scheme. Strontium (Sr) and iron (Fe) were chosen as A and B site elements with A' being lanthanum (La), samarium (Sm) or yttrium (Y), and B' being manganese (Mn) or titanium (Ti) to tailor their equilibrium oxygen partial pressures (PO2s) for CO2-splitting and methane partial oxidation. DFT calculations were performed for predictive optimization of the oxide materials whereas experimental investigation confirmed the DFT-predicted redox performance. The redox kinetics of the RCs improved significantly by 1 wt% ruthenium (Ru) impregnation without affecting their redox thermodynamics. Ru-impregnated LaFe0.375Mn0.625O3 (A = 0, A' = La, B = Fe, and B' = Mn) was the most promising RC in terms of its superior redox performance (CH4/CO2 conversion >90% and CO selectivity ∼95%) at 800 °C. Long-term redox testing over Ru-impregnated LaFe0.375Mn0.625O3 indicated a stable performance during the first 30 cycles followed by an ∼25% decrease in the activity during the last 70 cycles. Air treatment was effective to reactivate the redox catalyst. Detailed characterizations revealed the underlying mechanism of the redox catalyst deactivation and reactivation. This study not only validated a DFT-guided mixed oxide design strategy for CO2 utilization but also provides potentially effective approaches to enhance redox kinetics and long-term redox catalyst performance.}, journal={NANOSCALE}, author={Iftikhar, Sherafghan and Martin, William and Wang, Xijun and Liu, Junchen and Gao, Yunfei and Li, Fanxing}, year={2022}, month={Nov} }
 @article{zhu_gao_wang_haribal_liu_neal_bao_wu_wang_li_2021, title={A tailored multi-functional catalyst for ultra-efficient styrene production under a cyclic redox scheme}, volume={12}, ISSN={["2041-1723"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85101732148&partnerID=MN8TOARS}, DOI={10.1038/s41467-021-21374-2}, abstractNote={Styrene is an important commodity chemical that is highly energy and CO2 intensive to produce. We report a redox oxidative dehydrogenation (redox-ODH) strategy to efficiently produce styrene. Facilitated by a multifunctional (Ca/Mn)1-xO@KFeO2 core-shell redox catalyst which acts as (i) a heterogeneous catalyst, (ii) an oxygen separation agent, and (iii) a selective hydrogen combustion material, redox-ODH auto-thermally converts ethylbenzene to styrene with up to 97% single-pass conversion and >94% selectivity. This represents a 72% yield increase compared to commercial dehydrogenation on a relative basis, leading to 82% energy savings and 79% CO2 emission reduction. The redox catalyst is composed of a catalytically active KFeO2 shell and a (Ca/Mn)1-xO core for reversible lattice oxygen storage and donation. The lattice oxygen donation from (Ca/Mn)1-xO sacrificially stabilizes Fe3+ in the shell to maintain high catalytic activity and coke resistance. From a practical standpoint, the redox catalyst exhibits excellent long-term performance under industrially compatible conditions.}, number={1}, journal={NATURE COMMUNICATIONS}, publisher={Springer Science and Business Media LLC}, author={Zhu, Xing and Gao, Yunfei and Wang, Xijun and Haribal, Vasudev and Liu, Junchen and Neal, Luke M. and Bao, Zhenghong and Wu, Zili and Wang, Hua and Li, Fanxing}, year={2021}, month={Feb} }
 @article{gu_gao_iftikhar_li_2021, title={Ce stabilized Ni-SrO as a catalytic phase transition sorbent for integrated CO2 capture and CH4 reforming}, volume={12}, ISSN={["2050-7496"]}, url={https://doi.org/10.1039/D1TA09967A}, DOI={10.1039/d1ta09967a}, abstractNote={Integration of carbon dioxide capture from flue gas with dry reforming of CH4 represents an attractive approach for CO2 utilization. The selection of a suitable bifunctional material serving as a...}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, publisher={Royal Society of Chemistry (RSC)}, author={Gu, Haiming and Gao, Yunfei and Iftikhar, Sherafghan and Li, Fanxing}, year={2021}, month={Dec} }
 @article{wang_gao_liu_song_liu_guo_2021, title={Core-shell Na2WO4/CuMn2O4 oxygen carrier with high oxygen capacity for chemical looping oxidative dehydrogenation of ethane}, volume={303}, ISSN={["1873-7153"]}, DOI={10.1016/j.fuel.2021.121286}, abstractNote={Chemical looping oxidative dehydrogenation (CL-ODH) of ethane utilizes lattice oxygen of oxygen carrier, to substitute molecular oxygen, which makes high oxygen capacity as significant as ethane conversion and ethylene selectivity. Promoter were usually used to increased ethylene selectivity of bare oxygen carriers, but the overall oxygen capacity is limited to 3 wt%. In the current work, a core-shell oxygen carrier with Na2WO4 as the shell material and spinel-type CuMn2O4 as oxygen source was prepared. The core-shell structure were characterized by SEM, HTEM and XPS. Deep reduction with thirty consecutive ethane pulses was exhibited in a fixed bed. At 720 °C, up to 58.8% ethane conversion, 86.4% ethylene selectivity, and effective oxygen capacity up to 4.8 wt% were achieved with H2 conversion > 90%. Furthermore, in the light of effective oxygen capacity, the phase transformation from CuMn2O4 to Cu, MnO, Mn3O4 and CuMnO2 is determined as the desired phase change for this CL-ODH process. The connection between the dynamic phase change and the enlarged oxygen capacity will also shed light in future oxygen carrier design for chemical looping processes for chemical productions.}, journal={FUEL}, author={Wang, Tao and Gao, Yunfei and Liu, Yongzhuo and Song, Minghang and Liu, Jingjing and Guo, Qingjie}, year={2021}, month={Nov} }
 @article{iftikhar_jiang_gao_liu_gu_neal_li_2021, title={LaNixFe1-xO3-delta as a Robust Redox Catalyst for CO2 Splitting and Methane Partial Oxidation}, volume={35}, ISSN={["1520-5029"]}, DOI={10.1021/acs.energyfuels.1c02258}, abstractNote={The current study reports LaNi0.5Fe0.5O3−δ as a robust redox catalyst for CO2 splitting and methane partial oxidation at relatively low temperatures (∼700 °C) in the context of a hybrid redox process. Specifically, perovskite-structured LaNixFe1–xO3−δ (LNFs) with nine different compositions (x = 0.05–0.5) were prepared and investigated. Among the samples evaluated, LaNi0.4Fe0.6O3−δ and LaNi0.5Fe0.5O3−δ showed superior redox performance, with ∼90% CO2 and methane conversions and >90% syngas selectivity. The standalone LNFs also demonstrated performance comparable to that of LNF promoted by mixed conductive Ce0.85Gd0.1Cu0.05O2−δ (CGCO). Long-term testing of LaNi0.5Fe0.5O3−δ indicated that the redox catalyst gradually loses its activity over repeated redox cycles, amounting to approximately 0.02% activity loss each cycle, averaged over 500 cycles. This gradual deactivation was found to be reversible by deep oxidation with air. Further characterizations indicated that the loss of activity resulted from a slow accumulation of iron carbide (Fe3C and Fe5C2) phases, which cannot be effectively removed during the CO2 splitting step. Reoxidation with air removed the carbide phases, increased the availability of Fe for the redox reactions via solid-state reactions with La2O3, and decreased the average crystallite size of La2O3. Reactivating the redox catalyst periodically, e.g., once every 40 cycles, was shown to be highly effective, as confirmed by operating the redox catalyst over 900 cumulative cycles while maintaining satisfactory redox performance.}, number={17}, journal={ENERGY & FUELS}, author={Iftikhar, Sherafghan and Jiang, Qiongqiong and Gao, Yunfei and Liu, Junchen and Gu, Haiming and Neal, Luke and Li, Fanxing}, year={2021}, month={Sep}, pages={13921–13929} }
 @article{wang_gao_wang_cai_chung_iftikhar_wang_li_2021, title={Liquid Metal Shell as an Effective Iron Oxide Modifier for Redox-Based Hydrogen Production at Intermediate Temperatures}, volume={11}, ISSN={["2155-5435"]}, url={https://doi.org/10.1021/acscatal.1c02102}, DOI={10.1021/acscatal.1c02102}, abstractNote={This study reports molten metals (bismuth, indium, and tin) as effective modifiers for iron-based redox catalysts in the context of chemical looping-based hydrogen production at intermediate temperatures (450–650 °C) from low-calorific-value waste gas (e.g., blast furnace gas). The effects of the bismuth promoter on both the surface and bulk properties of iron oxides were studied in detail. Transmission electron microscopy and energy-dispersive spectroscopy (TEM-EDS), low-energy ion scattering (LEIS), Raman spectroscopy, and 18O2 exchange experiment revealed that the bismuth modifier forms an overlayer covering the bulk iron (oxides), leading to better anti-coking properties compared to reference La0.8Sr0.2FeO3- and Ce0.9Gd0.1O2-supported iron oxides. The Bi-modified sample also exhibited improved anti-sintering properties and high redox activity, resulting in a 4-fold increase in oxygen capacity compared to pristine Fe2O3 (28.9 vs 6.4 wt %) under a cyclic redox reaction at 550 °C. Meanwhile, a small amount of bismuth is doped into the iron oxide structure to effectively enhance its redox properties by lowering the oxygen vacancy formation energy (from 3.1 to 2.1 eV) and the energy barrier for vacancy migration, as confirmed by the experimental results and density functional theory (DFT) calculations. Reactive testing indicates that Bi-modified redox catalysts are highly active to convert low-calorific-value waste gases such as blast furnace gas. Our study also indicates that this strategy can be generalized to low-melting-point metals such as Bi, In, and Sn for iron oxide modification in chemical looping processes.}, number={16}, journal={ACS CATALYSIS}, publisher={American Chemical Society (ACS)}, author={Wang, Iwei and Gao, Yunfei and Wang, Xijun and Cai, Runxia and Chung, Chingchang and Iftikhar, Sherafghan and Wang, Wei and Li, Fanxing}, year={2021}, month={Aug}, pages={10228–10238} }
 @article{li_gao_zhao_li_he_lv_huang_2021, title={Mg-doped La1.6Sr0.4FeCoO6 for anaerobic oxidative dehydrogenation of ethane using surface-absorbed oxygen with tuned electronic structure}, volume={216}, ISSN={["1873-7188"]}, DOI={10.1016/j.fuproc.2021.106771}, abstractNote={Chemical looping oxidative dehydrogenation (CL-ODH) of ethane is a promising approach for converting ethane as a fuel from shale to value-added ethylene in a more economical way. In this work, La1.6Sr0.4FeCoO6 (LSFC) with earth-abundant Mg dopants were investigated for CL-ODH of ethane in the temperature between 650 and 750 °C. Mg doping substantially increased ethylene selectivity of LSFC, and up to 52.9%-ethane conversion and 89.4%-ethylene selectivity were achieved at 725 °C. X-ray photoelectron spectroscopy (XPS) indicated that Mg-doping in LSFC induced surface electron donation from Sr site to O site, rendering a surface with more electron-rich oxygen species. This was further confirmed with O2-temperature-programmed desorption. It was determined that these surface electron-rich oxygen species were essential for high ethylene selectivities. Consecutive ethane pulse and detailed XPS and X-Ray diffraction characterizations were further used to pinpoint the exact roles of different surface/bulk oxygen species. The results indicated that surface-absorbed peroxide (O22−surface) species played the most critical role in selective ethane CL-ODH and the use of O22−surface can be a general principle for designing CL-ODH catalysts.}, journal={FUEL PROCESSING TECHNOLOGY}, author={Li, Ming and Gao, Yunfei and Zhao, Kun and Li, Haibin and He, Fang and Lv, Pengmei and Huang, Zhen}, year={2021}, month={Jun} }
 @article{liu_gao_wang_li_2021, title={Molten-salt-mediated carbon dioxide capture and superequilibrium utilization with ethane oxidative dehydrogenation}, volume={2}, ISSN={["2666-3864"]}, DOI={10.1016/j.xcrp.2021.100503}, abstractNote={Existing CO2-mediated oxidative dehydrogenation (CO2-ODH) of ethane has yet to demonstrate >60% single-pass CO yield due to the intrinsic equilibrium limitations. We report a unique approach with mixed molten carbonates as a reaction medium for CO2-ODH, which strategically partitions the CO2-ODH reactions into gas and molten-salt phases and facilitates integrated CO2 capture from power plant flue gases. An 89% CO yield was achieved at 770°C, doubling the equilibrium limitation of conventional CO2-ODH. The high CO yield in turn enhances ethylene formation. Further characterizations confirmed that molten-salt mediated ODH (MM-ODH) proceeds through a gas-phase cracking and molten-salt mediated reverse water-gas-shift reaction pathway. Based on this understanding, thermodynamic analysis and ab initio molecular dynamics simulations were conducted to develop general principles to optimize the molten-salt reaction medium. Process analyses confirm that MM-ODH has the potential to be significantly more efficient for CO2 capture and utilization than conventional CO2-ODH.}, number={7}, journal={CELL REPORTS PHYSICAL SCIENCE}, author={Liu, Junchen and Gao, Yunfei and Wang, Xijun and Li, Fanxing}, year={2021}, month={Jul} }
 @article{hao_gao_liu_dudek_neal_wang_liu_li_2021, title={Zeolite-assisted core-shell redox catalysts for efficient light olefin production via cyclohexane redox oxidative cracking}, volume={409}, ISSN={["1873-3212"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85098692807&partnerID=MN8TOARS}, DOI={10.1016/j.cej.2020.128192}, abstractNote={This study reports a highly effective redox catalyst platform, i.e. composites of metal-exchanged ZSM5 and CaMn0.75Fe0.25O3@Na2WO4, for “low temperature” (<650 °C) redox oxidative cracking (ROC) of naphtha using a cyclohexane model compound. TEM-EDX showed that Na2WO4 shell covers the CaMn0.75Fe0.25O3 bulk and the zeolite + CaMn0.75Fe0.25O3@Na2WO4 composite can achieve autothermal conversion of cyclohexane under a cyclic redox scheme by selective oxidation of by-product H2 to H2O. Meanwhile, NH3-TPD and pyridine FTIR experiments confirmed that the Brönsted acidity of ZSM5 was primarily responsible for cyclohexane activation. Compared to each catalyst component alone, the synergistic effect of the composite redox catalysts resulted in substantially higher olefin yield (up to 75%), lower alkane yield (~5%), lower aromatic yield (~10%), and higher lattice oxygen utilization (up to 4 wt.cat%). Based on TGA-DSC experiments and ASPEN Plus analysis, the multi-functional redox catalysts facilitate autothermal conversion of cyclohexane with high lattice oxygen utilization from the redox catalysts. Due to the highly effective redox catalysts performance and the ease for heat integration, the novel ROC process has the potential for more energy-efficient light olefins production with significantly reduced CO2 emissions when compared to naphtha steam cracking.}, journal={CHEMICAL ENGINEERING JOURNAL}, author={Hao, Fang and Gao, Yunfei and Liu, Junchen and Dudek, Ryan and Neal, Luke and Wang, Shuang and Liu, Pingle and Li, Fanxing}, year={2021}, month={Apr} }
 @article{gao_wang_liu_huang_zhao_zhao_wang_li_2020, title={A molten carbonate shell modified perovskite redox catalyst for anaerobic oxidative dehydrogenation of ethane}, volume={6}, ISSN={["2375-2548"]}, url={https://doi.org/10.1126/sciadv.aaz9339}, DOI={10.1126/sciadv.aaz9339}, abstractNote={Molten carbonate leads to a 10-fold ethylene yield increase by facilitating oxygen transport while blocking nonselective sites. Acceptor-doped, redox-active perovskite oxides such as La0.8Sr0.2FeO3 (LSF) are active for ethane oxidation to COx but show poor selectivity to ethylene. This article reports molten Li2CO3 as an effective “promoter” to modify LSF for chemical looping–oxidative dehydrogenation (CL-ODH) of ethane. Under the working state, the redox catalyst is composed of a molten Li2CO3 layer covering the solid LSF substrate. The molten layer facilitates the transport of active peroxide (O22−) species formed on LSF while blocking the nonselective sites. Spectroscopy measurements and density functional theory calculations indicate that Fe4+→Fe3+ transition is responsible for the peroxide formation, which results in both exothermic ODH and air reoxidation steps. With >90% ethylene selectivity, up to 59% ethylene yield, and favorable heat of reactions, the core-shell redox catalyst has an excellent potential to be effective for intensified ethane conversion. The mechanistic findings also provide a generalized approach for designing CL-ODH redox catalysts.}, number={17}, journal={SCIENCE ADVANCES}, publisher={American Association for the Advancement of Science (AAAS)}, author={Gao, Yunfei and Wang, Xijun and Liu, Junchen and Huang, Chuande and Zhao, Kun and Zhao, Zengli and Wang, Xiaodong and Li, Fanxing}, year={2020}, month={Apr} }
 @article{dai_zhu_yan_su_gao_zhang_ke_parsons_2020, title={An Advanced Dual-Function MnO2-Fabric Air Filter Combining Catalytic Oxidation of Formaldehyde and High-Efficiency Fine Particulate Matter Removal}, volume={30}, ISSN={["1616-3028"]}, url={https://doi.org/10.1002/adfm.202001488}, DOI={10.1002/adfm.202001488}, abstractNote={Comprehensive treatment of indoor contaminants such as volatile organic compounds (VOCs) and fine particulate matter (PM2.5) using transition metal oxide catalysts or functional fibrous filters has gained substantial attention recently. However, coupling VOC oxidation catalysts into high‐performance filter systems remains a challenge. Herein, an overall solution to strongly bind manganese dioxide (MnO2) nanocrystals onto polypropylene (PP) nonwoven fabrics is provided. For the first time, uniform heterogeneous nucleation and growth of MnO2 onto PP nonwoven fabrics using intermediate inorganic nucleation films, including Al2O3, TiO2, and ZnO, formed conformally on the fabrics via atomic layer deposition (ALD) are demonstrated. How different ALD thin films influence the crystallinity, morphology, surface area, and surface oxygen species of the MnO2 grown ALD‐coated PP fibers is further investigated. In addition to uniformity and integrity, ZnO thin films give rise to MnO2 crystals with the largest fraction of available surface oxygen, enabling 99.5% catalytic oxidation of formaldehyde within 60 min. Moreover, the metal oxide filters provide excellent PM removal efficiencies (ePM), achieving ePM2.5 90% and ePM10 98%, respectively, making the approach an outstanding method to produce fully dual‐functional filtration media.}, number={42}, journal={ADVANCED FUNCTIONAL MATERIALS}, publisher={Wiley}, author={Dai, Zijian and Zhu, Jie and Yan, Jiaqi and Su, Jiafei and Gao, Yunfei and Zhang, Xing and Ke, Qinfei and Parsons, Gregory N.}, year={2020}, month={Oct} }
 @article{jiang_gao_haribal_qi_liu_hong_jin_li_2020, title={Mixed conductive composites for 'Low-Temperature' thermo-chemical CO(2)splitting and syngas generation}, volume={8}, ISSN={["2050-7496"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85087820008&partnerID=MN8TOARS}, DOI={10.1039/d0ta03232h}, abstractNote={An effective strategy to design platinum group metal (PGM) free redox catalysts for “low temperature” CO2 splitting followed with methane partial oxidation was proposed and validated. Composites of mixed ionic-electronic conductive (MIEC) oxides were found to be highly effective at relatively low temperatures (600–750 °C). Specifically, perovskite structured LaNi0.35Fe0.65O3 and rock salt structured Ce0.85Gd0.1Cu0.05O2−δ, as two compatible yet structurally distinct MIEC oxides, were integrated into composite redox catalyst particles. Resulting from the synergistic effect of the two MIEC phases, 90% CO2 to CO conversion was demonstrated at 750 °C. Up to 90% methane conversion with 96% CO selectivity was also achieved in the methane POx step. The redox catalysts were characterized in detail to illustrate the underlying mechanisms for the synergistic effects. Electrical conductivity relaxation (ECR) measurements indicated significantly lowered activation energy for lattice oxygen (O2−) migration (0.43 eV). The enhanced oxygen migration in turn led to reversible exsolution of active transition metal nanoparticles (Ni–Fe alloy) from the mixed oxide, serving as active sites for methane activation while further enhancing lattice oxygen exchange, as confirmed by in situ X-ray diffraction and transmission electron microscopy. As a result, the composite redox catalysts demonstrate superior redox activity, coke resistance, and long term redox stability, making them potentially suitable for CO2 utilization and methane partial oxidation under a hybrid redox process scheme.}, number={26}, journal={JOURNAL OF MATERIALS CHEMISTRY A}, publisher={Royal Society of Chemistry (RSC)}, author={Jiang, Qiongqiong and Gao, Yunfei and Haribal, Vasudev Pralhad and Qi, He and Liu, Xingbo and Hong, Hui and Jin, Hongguang and Li, Fanxing}, year={2020}, month={Jul}, pages={13173–13182} }
 @article{hao_gao_neal_dudek_li_chung_guan_liu_liu_li_2020, title={Sodium tungstate-promoted CaMnO3 as an effective, phase-transition redox catalyst for redox oxidative cracking of cyclohexane}, volume={385}, ISSN={["1090-2694"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85082646635&partnerID=MN8TOARS}, DOI={10.1016/j.jcat.2020.03.022}, abstractNote={Oxidative cracking, which combines catalytic oxidation and cracking reactions, represents a promising approach to reduce the energy and carbon intensities for light olefin production from naphtha. The need to co-feed gaseous oxygen with hydrocarbons, however, leads to significant COx formation and safety concerns. The cost and energy consumption associated with air separation also affects its economic attractiveness. In this study, we investigated a redox oxidative cracking (ROC) scheme and evaluated perovskites (La0.8Sr0.2FeO3 and CaMnO3) and Na2WO4-promoted perovskite (La0.8Sr0.2FeO3@Na2WO4 and CaMnO3@Na2WO4) as the redox catalysts for ROC. CaMnO3@Na2WO4 redox catalyst shows high activity, selectivity, and stability for light olefin production from cyclohexane. Operated under a redox oxidative cracking (ROC) scheme, CaMnO3@Na2WO4 enhances the catalytic cracking of cyclohexane, while showing high selectivity towards hydrogen combustion with its built-in, active lattice oxygen. Over three-fold increase in olefin yield compared to thermal cracking and 35% yield increase compared to conventional O2-cofeed oxidative cracking were achieved. Low energy ion scattering (LEIS), X-ray photoelectric spectroscopy (XPS), and differential scanning calorimetry (DSC) indicated a core-shell structure, where a molten Na2WO4 layer covers the CaMnO3 core. Na2WO4 modifies the oxygen donation behavior of CaMnO3 and provides a catalytically active surface for cyclohexane activation. In-situ XRD revealed that CaMnO3@Na2WO4 exhibited excellent structural stability and regenerability. The transformation of Mn4+ ↔ Mn3+ ↔ Mn2+ in CaMnO3, facilitated by reversible phase transition to (Ca/Mn)O solid solution, is responsible for the lattice oxygen donation and uptake during redox cycles. Electrochemical impedance spectroscopy (EIS) measurements further confirmed that the oxygen species were transported through the molten Na2WO4 layer to participate in ROC. These findings offer mechanistic insights to design effective redox catalysts for hydrocarbon valorization using the chemical looping strategy.}, journal={JOURNAL OF CATALYSIS}, author={Hao, Fang and Gao, Yunfei and Neal, Luke and Dudek, Ryan B. and Li, Wenyuan and Chung, Chingchang and Guan, Bo and Liu, Pingle and Liu, Xingbo and Li, Fanxing}, year={2020}, month={May}, pages={213–223} }
 @article{gao_wang_hao_dai_li_2020, title={Zeolite-Perovskite Composites as Effective Redox Catalysts for Autothermal Cracking of n-Hexane}, volume={8}, ISSN={["2168-0485"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85094838280&partnerID=MN8TOARS}, DOI={10.1021/acssuschemeng.0c04207}, abstractNote={This study reports highly effective, multifunctional ZSM5/CaMnO3@Na2WO4 composite redox catalysts for redox oxidative cracking (ROC) of n-hexane. Compared to the previously reported redox catalysts...}, number={38}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Gao, Yunfei and Wang, Shuang and Hao, Fang and Dai, Zijian and Li, Fanxing}, year={2020}, month={Sep}, pages={14268–14273} }
 @misc{gao_neal_ding_wu_baroi_gaffney_li_2019, title={Recent Advances in Intensified Ethylene Production-A Review}, volume={9}, ISSN={["2155-5435"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85071911366&partnerID=MN8TOARS}, DOI={10.1021/acscatal.9b02922}, abstractNote={Steam cracking is a well-established commercial technology for ethylene production. Despite decades of optimization efforts, the process is, nevertheless, highly energy and carbon intensive. This r...}, number={9}, journal={ACS CATALYSIS}, author={Gao, Yunfei and Neal, Luke and Ding, Dong and Wu, Wei and Baroi, Chinmoy and Gaffney, Anne M. and Li, Fanxing}, year={2019}, month={Sep}, pages={8592–8621} }
 @article{tian_dudek_gao_zhao_li_2019, title={Redox oxidative cracking of n-hexane with Fe-substituted barium hexaaluminates as redox catalysts}, volume={9}, ISSN={["2044-4761"]}, url={https://doi.org/10.1039/C8CY02530D}, DOI={10.1039/c8cy02530d}, abstractNote={Promoted hexaaluminate redox catalysts achieved excellent olefin yield while allowing autothermal redox oxidative cracking of naphtha with low COx formation.}, number={9}, journal={CATALYSIS SCIENCE & TECHNOLOGY}, publisher={Royal Society of Chemistry (RSC)}, author={Tian, Xin and Dudek, Ryan B. and Gao, Yunfei and Zhao, Haibo and Li, Fanxing}, year={2019}, month={May}, pages={2211–2220} }
 @article{gao_haeri_he_li_2018, title={Alkali Metal-Promoted LaxSr2-xFeO4-delta Redox Catalysts for Chemical Looping Oxidative Dehydrogenation of Ethane}, volume={8}, ISSN={["2155-5435"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85042879284&partnerID=MN8TOARS}, DOI={10.1021/acscatal.7b03928}, abstractNote={Chemical looping oxidative dehydrogenation (CL-ODH) represents a redox approach to convert ethane into ethylene under an autothermal scheme. Instead of using gaseous oxygen, CL-ODH utilizes lattice oxygen in transition metal oxides, which acts as an oxygen carrier or redox catalyst, to facilitate the ODH reaction. The oxygen-deprived redox catalyst is subsequently regenerated with air and releases heat. The current study investigated alkali metal (Li, Na, and/or K)-promoted LaxSr2–xFeO4−δ (LaSrFe) as redox catalysts for CL-ODH of ethane. While unpromoted LaSrFe exhibited poor ethylene selectivity, addition of Na or K promoter achieved up to 61% ethane conversion and 68% ethylene selectivity at 700 °C. The promotional effect of K on LaSrFe was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), low-energy ion scattering spectroscopy (LEIS), transmission electron microscopy (TEM), O2-temperature-programmed desorption (TPD), H2-temperature-programmed reduction (TPR), and 18O2...}, number={3}, journal={ACS CATALYSIS}, author={Gao, Yunfei and Haeri, Farrah and He, Fang and Li, Fanxing}, year={2018}, month={Mar}, pages={1757–1766} }
 @article{gao_neal_li_2016, title={Li-Promoted LaxSr2-xFeO4-delta Core-Shell Redox Catalysts for Oxidative Dehydrogenation of Ethane under a Cyclic Redox Scheme}, volume={6}, ISSN={["2155-5435"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84994627994&partnerID=MN8TOARS}, DOI={10.1021/acscatal.6b01399}, abstractNote={Chemical looping oxidative dehydrogenation (CL-ODH) of ethane utilizes a transition metal oxide based oxygen carrier, also known as a redox catalyst, to convert ethane into ethylene under an autothermal cyclic redox scheme. The current study investigates a Li-promoted LaxSr2–xFeO4−δ (LaSrFe) redox catalyst for CL-ODH reactions. While LaSrFe without Li promoter exhibits low ethylene selectivity, addition of Li leads to high selectivity/yield and good regenerability. Up to 61% ethane conversion and 90% ethylene selectivity are achieved with Li-promoted LaSrFe. Further characterization indicates that the Li-promoted LaSrFe redox catalyst consists of LiFeO2 (disordered rock salt) and LaSrFe (Ruddlesden–Popper) phases. Moreover, the surface of the redox catalysts is enriched with Li cations. It is also determined the LaSrFe phase contributes to oxygen storage and donation, whereas the activity and selectivity of the redox catalysts are modified by the Li promoter: while oxygen for the CL-ODH reaction is suppli...}, number={11}, journal={ACS CATALYSIS}, author={Gao, Yunfei and Neal, Luke M. and Li, Fanxing}, year={2016}, month={Nov}, pages={7293–7302} }