Article
Engineering, Chemical
Junko Uchisawa, Akira Obuchi, Asuka Yamamoto, Shunsuke Suzuki, Norifumi Mizushima, Shigenobu Hayashi
Summary: The increase in water vapor concentration accelerates the hydrothermal deterioration of Cu-SSZ-13 catalysts, leading to a decrease in catalytic activity. The deterioration process can be divided into two stages: a first stage involving a decrease in acid amount while retaining structure, and a second stage involving a decrease in active sites due to Cu aggregation and structure collapse.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Chemistry, Applied
Aiyong Wang, Ying Chen, Eric D. Walter, Nancy M. Washton, Tamas Varga, Yilin Wang, Janos Szanyi, Yong Wang, Charles H. F. Peden, Feng Gao
Summary: The model Cu/SAPO-34 SCR catalyst with isolated Cu(II) ions deactivates irreversibly after storage due to the attack of water molecules on active sites, leading to the formation of copper-aluminate-like species upon thermal treatment. This deactivation mechanism does not require significant degradation of the SAPO-34 support.
Article
Chemistry, Physical
Yiqing Wu, Tahrizi Andana, Yilin Wang, Ying Chen, Eric D. Walter, Mark H. Engelhard, Kenneth G. Rappe, Yong Wang, Feng Gao, Unmesh Menon, Rohil Daya, Dylan Trandal, Hongmei An, Yuhui Zha, Krishna Kamasamudram
Summary: Understanding aging mechanisms is crucial for the development and maintenance of SCR catalysts. Through comparative studies on different catalysts and their chemical characteristics, sulfur aging is found to play a significant role in catalyst degradation during real-world applications, while preserving the integrity of the catalyst support.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Physical
Jeongtak Kim, Jong Min Won, Soon Kwan Jeong, Kwangsun Yu, Kyuchul Shin, Sun-Mi Hwang
Summary: The effect of Fe doping on the low-temperature SCR activity of V/W/TiO2 catalysts was investigated. The addition of 0.5 wt% Fe resulted in significantly improved DeNO(x) efficiency. Fe, as a structural and electronic promoter, increased the dispersion and redox properties of the catalyst.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Jun-Kun Lai, Nicholas R. Jaegers, Bar Mosevitzky Lis, Mingyu Guo, Michael E. Ford, Eric Walter, Yong Wang, Jian Zhi Hu, Israel E. Wachs
Summary: Supported V2O5-WO3/TiO2 materials are employed as SCR catalysts for NOx emission control. The surface WOx sites stabilize the TiO2 phase, while the surface VOx sites mainly exist as V-5+O-x sites. The concentration of surface NH3* species is lower in hydrothermally treated catalysts, but SCR activity is comparable to calcined catalysts.
Article
Chemistry, Physical
Mengyang Chen, Wenru Zhao, Yingzhen Wei, Jinfeng Han, Junyan Li, Chang Sun, Donghai Mei, Jihong Yu
Summary: Incorporation of a small amount of lanthanum ions can enhance the NH3-SCR performance and hydrothermal stability of Cu-La-SSZ-13 zeolite catalysts. The introduction of lanthanum ions promotes the distribution of Cu ions at six-membered rings, leading to increased hydrothermal stability and NO conversion of Cu-La-SSZ-13. However, excessive lanthanum ions can result in the formation of inactive CuOx, leading to decreased catalytic activity and hydrothermal stability.
Article
Energy & Fuels
Yin Chen, Yanfen Liao, Lin Chen, Zhuofan Chen, Xiaoqian Ma
Summary: A new V-W/Ti SCR catalyst modified by Cu, Fe and Co was prepared for the simultaneous removal of NO and VOCs from coal-fired power plant flue gas. The experimental results showed that the catalyst had good denitration performance at low temperatures and high removal rates for benzene and toluene.
Article
Chemistry, Multidisciplinary
Zhitao Han, Huan Du, Duo Xu, Yu Gao, Shaolong Yang, Liguo Song, Jingming Dong, Xinxiang Pan
Summary: The addition of Sn to modify TiO2 supports improved the SO2 resistance and low-temperature SCR activity of FeMn/SnxTiO2 catalysts, leading to enhanced stability of the mesoporous structure. Sn doping also enhanced the redox properties, aiding in adsorption of NH3 species while suppressing SO2 adsorption, resulting in an improved Eley-Rideal mechanism for SCR reactions over the catalyst.
NEW JOURNAL OF CHEMISTRY
(2022)
Review
Energy & Fuels
Junyan Chen, Bin Guan, Ziqian Liu, Xingze Wu, Jiangfeng Guo, Chunzheng Zheng, Jiefei Zhou, Tianxu Su, Peicheng Han, Chuzhao Yang, Yaoyao Zhang, Bo Qin, Jintian Gao, Yuheng Yuan, Wenkai Xie, Nanxin Zhou, Zhen Huang
Summary: NH3-SCR, as a highly efficient and stable technology, is widely applied in the treatment of exhaust gases. This paper reviews the latest progress in NH3-SCR catalysts, including different categories and their synergistic effects, as well as the mechanisms of aging, poisoning, and N2O generation. Three strategies for improving the comprehensive performance of NH3-SCR catalysts are summarized: doping/modification, synthesis method improvement, and support structure improvement.
Article
Environmental Sciences
Tong Wu, Rui-tang Guo, Yi-hao You, Wei-guo Pan
Summary: This article summarizes the application and performance of core-shell structured catalysts in NH3-SCR and emphasizes their advantages in selectivity, activity, and anti-poisoning ability. It is of great significance for the development of novel catalyst designs with improved denitrification performance.
Article
Chemistry, Applied
Vasyl Marchuk, Xiaohui Huang, Vadim Murzin, Jan-Dierk Grunwaldt, Dmitry E. Doronkin
Summary: This study investigates the reaction mechanism and performance variation of bifunctional Fe-Pt ammonia slip catalysts, revealing the significant influence of active metal state on reaction conditions and catalyst bed layout. The study also examines the impact of non-equilibrium phenomena on catalytic performance.
TOPICS IN CATALYSIS
(2023)
Review
Energy & Fuels
Zhiwei Shi, Qingguo Peng, Jiaqiang E, Bo Xie, Jia Wei, Ruixue Yin, Guang Fu
Summary: This article systematically reviews the modification methods of catalysts in selective catalytic reduction (SCR) technology, analyzes the effects of various catalyst parameters on denitrification efficiency, and discusses the influences of spatial structure on catalytic effect. Additionally, it compares the performance of catalysts with different components and summarizes the current problems in catalyst research. The development of NH3-SCR technology is also prospected.
Article
Engineering, Environmental
De Fang, Kai Qi, Fengxiang Li, Feng He, Junlin Xie
Summary: Fe-SO4/TiO2 catalysts show different performances at high and low temperatures. The 20%Fe-SO4/TiO2 catalyst exhibits excellent sulfur tolerance.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Chemistry, Physical
Inhak Song, Se Won Jeon, Hwangho Lee, Do Heui Kim
Summary: Utilizing mechanochemical interactions to fabricate hybrid catalysts is an important emerging area in heterogeneous catalysis. This study reports the unusual deactivation of a vanadia catalyst and successfully resolves this issue through surface functionalization, resulting in a hybrid catalyst with superior sulfur resistance in low-temperature SCR.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Physical
Simon Schoenebaum, Juergen Dornseiffer, Peter Mauermann, Bernd Wolkenar, Stefan Sterlepper, Egbert Wessel, Riza Iskandar, Joachim Mayer, Thomas E. Weirich, Stefan Pischinger, Olivier Guillon, Ulrich Simon
Summary: Two commercially available lean NOx trap (LNT) catalysts were found to exhibit similar NOx storage behavior but showed significant differences during regeneration, indicating potential for optimizing storage and regeneration performance.
Article
Chemistry, Applied
D. William Brookshear, Josh A. Pihl, Todd J. Toops, Brian West, Vitaly Prikhodko
Article
Chemistry, Applied
Vitaly Y. Prikhodko, James E. Parks, Josh A. Pihl, Todd J. Toops
Article
Chemistry, Applied
Andrew P. Wong, Eleni A. Kyriakidou, Todd J. Toops, John R. Regalbuto
Article
Chemistry, Physical
Jingke Mo, Ryan R. Dehoff, William H. Peter, Todd J. Toops, Johney B. Green, Feng-Yuan Zhang
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2016)
Article
Chemistry, Applied
Andrea Strzelec, Randy L. Vander Wal, Thomas N. Thompson, Todd J. Toops, C. Stuart Daw
TOPICS IN CATALYSIS
(2016)
Article
Chemistry, Physical
Andreas Gremminger, Josh Pihl, Maria Casapu, Jan-Dierk Grunwaldt, Todd J. Toops, Olaf Deutschmann
APPLIED CATALYSIS B-ENVIRONMENTAL
(2020)
Review
Energy & Fuels
Yujun Wang, Carl J. Kamp, Yuesen Wang, Todd J. Toops, Changsheng Su, Ruoqian Wang, Jian Gong, Victor W. Wong
Article
Chemistry, Applied
Tanya Shirman, Todd J. Toops, Elijah Shirman, Anna Shneidman, Sissi Liu, Keeve Gurkin, Jack Alvarenga, Michael P. Lewandowski, Michael Aizenberg, Joanna Aizenberg
Summary: The development of novel, efficient, and stable catalytic materials is becoming increasingly urgent due to the detrimental effects of anthropogenic air pollution. Tightening regulations and improved engine design require next-generation catalysts with improved low-temperature activity and high-temperature stability. The innovative approach of incorporating sacrificial composite templates allows for more efficient utilization of precious metals and enhanced overall catalyst performance at reduced loadings.
Article
Chemistry, Applied
Eleni A. Kyriakidou, Jungkuk Lee, Jae-Soon Choi, Michael Lance, Todd J. Toops
Summary: The study showed that different ion-exchanged zeolite samples exhibited varying abilities in adsorbing propylene and NO, with silver ion-exchanged BEA zeolites showing strong adsorption for propylene and palladium ion-exchanged BEA zeolites demonstrating the greatest oxidation ability during desorption.
Article
Chemistry, Physical
Daekun Kim, Todd J. Toops, Ke Nguyen, Michael J. Lance, Jun Qu
Summary: The study evaluated the impact of different additives on the performance of three-way catalysts in an engine bench test, showing that ZDDP2 and IL+ZDDP2-aged TWC samples had a more significant degradation on water-gas shift reaction and oxygen storage capacity compared to ZDDP1 and IL+ZDDP1-aged TWC samples. This was confirmed by XRD patterns and ICP-OES analysis, revealing higher phosphorus content in the washcoat of ZDDP2 and IL+ZDDP2-aged TWC samples.
Article
Chemistry, Physical
Todd J. Toops, Pranaw Kunal
Summary: With stricter emission control regulations, multi-functional catalyst systems are becoming more important for low-temperature operation. This study investigates different multi-component catalyst systems and their effectiveness in reducing emissions under cold-start conditions. A merit function is developed to evaluate the effectiveness of each system relative to emission standards. The results show that a 1:1:4 ratio of PNA:HCT:DOC is the most effective configuration for emissions reduction.
Article
Engineering, Mechanical
Daekun Kim, Todd J. Toops, Ke Nguyen, Michael J. Lance, Jun Qu
Summary: The impact of a boron-containing lubricant oil additive (BR) on the performance of a Pd/Rh-based three-way catalyst (TWC) is investigated and compared with the effects of no additive (NA) and the industry standard zinc dialkyl-dithiophosphate (ZDDP). Accelerated aging of the catalysts using a genset shows that the BR-aged TWC exhibits similar reactivity to the NA-aged TWC, while the ZDDP-aged TWC shows increased reactivity for certain gas species. Analytical techniques reveal the presence of boron in the BR-aged TWC samples, but no boron-related peaks are observed in the XRD pattern.
Article
Imaging Science & Photographic Technology
Martin L. Wissink, Todd J. Toops, Derek A. Splitter, Eric J. Nafziger, Charles E. A. Finney, Hassina Z. Bilheux, Louis J. Santodonato, Yuxuan Zhang
Summary: Neutron imaging is an attractive method for non-destructively probing objects or systems that are not accessible by conventional means. However, the low flux of neutron sources and limitations of existing detectors have restricted its applicability.
JOURNAL OF IMAGING
(2022)
Article
Engineering, Environmental
Daekun Kim, Todd J. Toops, Ke Nguyen, D. William Brookshear, Michael J. Lance, Jun Qu
EMISSION CONTROL SCIENCE AND TECHNOLOGY
(2020)
Article
Chemistry, Physical
Fredrik Gunnarsson, Josh A. Pihl, Todd J. Toops, Magnus Skoglundh, Hanna Harelind
APPLIED CATALYSIS B-ENVIRONMENTAL
(2017)
Article
Chemistry, Applied
Qingyuan Zheng, Jack H. Williams, Scott Elgersma, Mick D. Mantle, Andrew J. Sederman, G. Leendert Bezemer, Constant M. Guedon, Lynn F. Gladden
Summary: In this study, a pilot-scale fixed-bed reactor compatible with NMR/MRI was developed for Fischer-Tropsch synthesis. Multiple magnetic resonance techniques were applied to quantitatively characterize different product species within catalyst pellets, providing valuable information for catalyst and reactor optimization.
Article
Chemistry, Applied
Lisa Ramisch, Sebastian Pfaff, Sabrina M. Gericke, Edvin Lundgren, Johan Zetterberg
Summary: We present a combination of optical operando techniques that allow simultaneous measurement of adsorbed species on catalyst surfaces, monitoring of surface oxide formation, and imaging of the gas phase above the catalyst surface. The experimental setup was validated by studying CO oxidation on Pd(100) at different pressures, revealing the effects of pressure on the heterogeneous catalytic reaction.
Article
Chemistry, Applied
Marta Paniagua, Gabriel Morales, Juan A. Melero, Daniel Garcia-Salgado
Summary: The influence of common impurities in levulinic acid on the catalytic performance of different acid catalysts for bio-jet fuel production was studied. It was found that furfural had the greatest detrimental effect on catalyst performance, while propyl-sulfonic acid-modified SBA-15 and sulfonic acid resin Amberlyst-70 showed good regeneration ability.
Article
Chemistry, Applied
Jesus Tapiador, Pedro Leo, Guillermo Calleja, Gisela Orcajo
Summary: This study presents a new MOF material, Zn-URJC-13, with acid and basic sites, permanent porosity, and high affinity to CO2 molecules. The Zn-URJC-13 catalyst exhibits efficient performance in CO2 cycloaddition reactions and can be reused multiple times.
Article
Chemistry, Applied
Dan Zhao, Vita A. Kondratenko, Dmitry E. Doronkin, Shanlei Han, Jan-Dierk Grunwaldt, Uwe Rodemerck, David Linke, Evgenii V. Kondratenko
Summary: This study demonstrates the potential of cheap and commercially available Zr or Ti-based supports and ZnO to serve as active and selective catalysts for propane dehydrogenation (PDH). The catalytically active species formed in situ under PDH conditions consist of isolated ZnOx. ZnOx on the surface of LaZrOx shows the highest rate of propene formation.
Article
Chemistry, Applied
Hanbyeol Kim, Jung Rae Kim, Young-Kwon Park, Jeong-Myeong Ha, Jungho Jae
Summary: In this study, metal phosphates were used as catalysts for biomass conversion to produce sustainable aromatics through DielsAlder cycloaddition reactions. The effects of synthesis method, activation method, and P/Ti molar ratio on the structure and acid properties of titanium phosphate catalysts were systematically studied. The mesoporous titanium phosphate catalyst synthesized by hydrothermal method at 180℃ for 12 h followed by ethanol refluxing at 60℃ for 24 h at a molar P/Ti ratio of 1 showed the highest surface area and acid site density.
Article
Chemistry, Applied
Yasin Khani, Sumin Pyo, Kwang-Eun Jeong, Chul-Ung Kim, Moonis Ali Khan, Byong-Hun Jeon, Kun-Yi Andrew Lin, Siyoung Q. Choi, Young-Kwon Park
Summary: A protonated form of Zeolite Socony Mobil-5 (H-ZSM-5) catalyst was synthesized through a hydrothermal method using different sources of silica. The effect of loading the catalyst with yttrium, samarium, and gadolinium on the acidic properties was investigated. Among the metal-loaded catalysts, the Sm/LHZ catalyst showed the best performance in the methanol to propylene conversion due to its high amount of weak and intermediate acid sites, while the Gd-LHZ catalyst increased the selectivity towards ethane and propane.
Article
Chemistry, Applied
Michael Franc, Ivana Cisarova, Jan Vesely
Summary: The present study investigates an enantioselective cyclization of enals with imidazolone derivatives catalyzed by a combination of achiral Pd(0) complex and chiral secondary amine. Corresponding spirocyclic imidazolones were produced in high yields with moderate diastereoselectivity and excellent enantioselectivity. The developed co-operative catalytic methodology provides a highly substituted spirocyclic scaffold with four stereogenic centers under mild conditions.
Article
Chemistry, Applied
Mauro Alvarez, Jennifer Cueto, David P. Serrano, Pablo Marin, Salvador Ordonez
Summary: This study focuses on improving the formulation and preparation methods of catalysts for the production of dimethyl carbonate. By using suitable catalyst preparation methods and copper salt precursors, the researchers successfully produced catalysts with optimal performance for dimethyl carbonate formation.
Article
Chemistry, Applied
Claudia J. Keijzer, Luc C. J. Smulders, Dennie Wezendonk, Jan Willem de Rijk, Petra E. de Jongh
Summary: This study investigates the catalytic behavior of alpha-alumina supported silver catalysts in the presence of chloride. It is found that the particle size of silver can affect the selectivity of the catalyst, but different strategies lead to different results. In this size range, the selectivity of ethylene oxide is correlated to the Ag : Al2O3 surface ratio.
Article
Chemistry, Applied
Takeshi Aihara, Wataru Aoki, Michikazu Hara, Keigo Kamata
Summary: The development of acid-base bifunctional catalysts is important for promoting specific chemical transformations. In this study, Ti-based perovskite oxides were synthesized and used as catalysts for two C-C bond-forming reactions (cyanosilylation and Knoevenagel condensation). The highly pure SrTiO3 nanoparticles with a high specific surface area exhibited the highest catalytic performance, and could be easily recovered and reused.
Article
Chemistry, Applied
Olga Gorlova, Petra Pribylova, Eliska Vyskocilova, Katerina Peroutkova, Jan Kohout, Iva Paterova
Summary: This study investigates the Baeyer-Villiger oxidation of beta-cyclocitral using tin-modified mixed oxides as catalysts. The optimal reaction conditions and the effects of various factors on the reaction course and selectivity were determined. The results show that tin-modified mixed oxides exhibit high activity and selectivity in the oxidation reaction.
Article
Chemistry, Applied
M. I. Avila, M. M. Alonso-Doncel, L. Briones, G. Gomez-Pozuelo, J. M. Escola, D. P. Serrano, A. Peral, J. A. Botas
Summary: The catalytic fast pyrolysis of lignin using ion-exchanged zeolite catalysts showed significant improvements in bio-oil quality and the production of aromatic hydrocarbons and oxygenated compounds.
Article
Chemistry, Applied
Enrico Catizzone, Giorgia Ferrarelli, Paolo Bruno, Girolamo Giordano, Massimo Migliori
Summary: The acid-catalysed alcohol conversion reaction is a promising route for de-fossilization strategies. Research on pure alcohol conversion and simultaneous dehydration of mixed alcohols have shown different product compositions, with the type and distribution of acid sites affecting the reaction mechanism.
Article
Chemistry, Applied
Alireza Ranjbari, Juho Kim, Jihee Yu, Jiyun Kim, Mireu Park, Nayoung Kim, Kristof Demeestere, Philippe M. Heynderickx
Summary: This study investigated a novel kinetic model for the adsorption and photocatalytic degradation of methyl orange using commercial ZnO and reduced ZnO photocatalysts. The results provided new insights into the interaction of catalysts with molecules of different charges and compared with a previous study on methylene blue. The presence of oxygen vacancies in ZnO and their effects on adsorption and photocatalytic degradation were analyzed, and the photocatalytic degradation rate of reduced ZnO was found to increase significantly.