Article
Environmental Sciences
Se Won Jeon, Inhak Song, Hwangho Lee, Do Heui Kim
Summary: Vanadium oxide-based catalysts, such as V/MPTiO2, are promising for SCR of NO with NH3. Addition of W and Mo as promoters to V/MPTiO2 can enhance deNO(x) activities at low temperatures, while Sb tends to have a negative effect on SCR activity. The addition of W and Mo increases the polymerization in V/MPTiO2, generating more reactive vanadia species and leading to enhanced catalytic activity at low temperatures.
Article
Chemistry, Physical
Rongqiang Yin, Jianjun Chen, Liang Shan, Jianqiang Shi, Kun Yang, Hao Liu, Junhua Li
Summary: Selective catalytic reduction (SCR) over V2O5/TiO2-based catalysts is an efficient technology for removing nitrogen oxides from stationary sources in the presence of H2S and NOx. H2S was found to be six times more poisonous than SO2, with polymeric sulfate being the main contributor to H2S poisoning. The generation of sulfates was energetically more favorable under H2S, causing deposition and damage to V--O. Polymeric sulfate inhibited charge transfer and NH3 activation, resulting in significant SCR activity suppression. Unstable sulfur species were responsible for temporary deactivation during H2S poisoning. This work provides crucial insights for solving catalyst deactivation.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Energy & Fuels
Xiaoyu Li, Juan Chen, Chunmei Lu, Guangqian Luo, Hong Yao
Summary: The poisoning effect of Cr on the generation of N2O over gamma-Fe2O3 catalyst during the selective catalytic reduction of NOx with ammonia was observed. The mechanisms of N2O generation at different temperatures were identified, with Cr showing both promotion and inhibition effects on NOx conversion. The formation of FeCr2O4 in the poisoned catalyst was found to be a key factor in enhancing N2O production.
Article
Chemistry, Inorganic & Nuclear
Meilin Tao, Satoshi Ishikawa, Toru Murayama, Yusuke Inomata, Akiho Kamiyama, Wataru Ueda
Summary: Mo was successfully introduced into the vanadotungstate framework, resulting in materials with higher microporosity and stronger acidity, showing substantial catalytic activity for the selective catalytic reduction of NO with NH3.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Yiqing Zeng, Fengye Lyu, Yanan Wang, Shule Zhang, Qin Zhong, Zhaoxiang Zhong
Summary: This study investigates the formation of N2O during ammonia selective catalytic reduction (NH3-SCR) of NOx using MnOx-TiO2 catalyst. It is found that MnOx and TiO2 species serve as the main redox and acid sites, respectively. Increasing the Mn/Ti ratio expands the MnOx species layer on the TiO2 support, leading to an increase in redox sites but a decrease in surface acid sites, which contributes to the formation of N2O.
MOLECULAR CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Geumyeon Lee, Bora Ye, Myeung-jin Lee, Seung-Yeop Chun, Bora Jeong, Hong-Dae Kim, Jungho Jae, Taewook Kim
Summary: This study aims to produce more efficient catalysts for NOx removal by treating the TiO2 support with titanium isopropoxide (TTIP) to increase the number of catalytically active sites and facilitate the dispersal of active materials. The catalyst prepared at a TTIP loading of 5 wt% showed optimal performance due to increased thermal stability caused by high extent of W dispersion and the formation of V(4+) by the reaction of V5+ with surface Ti3+.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2022)
Article
Chemistry, Physical
Mengru Li, Sung Sakong, Axel Gross
Summary: This computational study examined the atomistic structure of mixed tungsta-vanadia monolayers on a TiO2 support, revealing the critical role of the stoichiometry of the tungsta-vanadia layers in their catalytic activity. Stable catalyst structures under operating conditions were determined, with identified active sites promising high catalytic activity for selective catalytic reduction by ammonia.
Article
Chemistry, Applied
Thi Phuong Thao Nguyen, Moon Hyeon Kim, Ki Hyuck Yang
Summary: The study investigates the roles of each composition and strongly-adsorbed NH3 in the formation and depression of N2O in NH3-SCR reactions with Fe2O3-promoted catalysts. Fe2O3 promotion allows successful reduction of N2O by strongly-adsorbed NH3 species, proposing a main pathway for depression of N2O formation.
Article
Chemistry, Physical
Liping Sheng, Songda Li, Zhaoxia Ma, Fei Wang, Hu He, Yi Gao, Beien Zhu, Yong Wang, Hangsheng Yang
Summary: The interaction of O-2 with NO reduction pathway greatly affects the NO removal efficiency and N2O formation during the NH3-SCR process over the Pd/CeO2 catalyst. Below 175 degrees C, fast-SCR is the main reaction route for NO removal, while in the temperature range of 175-250 degrees C, NH3 facilitates the reduction of NO but also induces the formation of N2O. Above 250 degrees C, NH3 is severely oxidized leading to excess N2O formation even in the presence of a low amount of O-2.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Energy & Fuels
Bolin Zhang, Lifeng Deng, Michael Liebau, Peiqiang Wang, Yingjie Ren, Bo Liu, Chunyun Luo, Roger Glaser, Shengen Zhang
Summary: This study successfully removed the tar species on the catalyst's surface and restored the catalyst's activity through an effective pyrolysis method. The optimized pyrolysis treatment maintained the mechanical properties of the catalyst at a high level and achieved efficient NO conversion and N-2 selectivity at a relatively low temperature range.
Article
Materials Science, Multidisciplinary
Guilin Mu, Shuai Liu, Qingjie Liu, Shanshan Liu, Xintang Zhang
Summary: In this study, TiO2 supported Ni and Ce catalysts with different morphologies were prepared. The Ni-Ce/flower-like TiO2 (NCFT) catalyst showed high performance (approximately 100% NO conversion and N-2 selectivity) in the temperature range of 250-450 degrees C, with resistance of around 80%. The order of activities observed was NCFT > NCST > NCPT > NCRT. The flower-like TiO2 carrier provided the largest specific surface area, facilitating the dispersion of active components. NCFT also exhibited excellent denitrification activity due to its abundance in Ni3+, Ce3+, and O alpha species, which supported excellent redox properties and provided more adsorption sites for the NH3-SCR reaction. However, its sulfur resistance stability needs further improvement due to its unique structure.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Chemistry, Physical
JungHun Shin, GyeongRyun Choi, SungChang Hong
Summary: The addition of Sb5+ to the WO3 structure improves NH3 adsorption and SCR performance, as well as enhances oxygen mobility at low temperatures. This catalyst has important potential applications in NH3-selective catalytic reduction of NO.
APPLIED SURFACE SCIENCE
(2022)
Article
Engineering, Environmental
Se Won Jeon, Inhak Song, Hwangho Lee, Joonwoo Kim, Youngchul Byun, Dong Jun Koh, Do Heui Kim
Summary: In this study, a hybrid catalyst was introduced, which exhibited better stability and sulfur tolerance during SO2 aging. The hybrid catalyst achieved the direct migration of ammonium bisulfate from the vanadia domain to the alumina domain through physical contact, rather than gas-phase adsorption. The surface properties of the mixed alumina played an important role in its affinity to ammonium bisulfate and reusability.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Physical
Wei Zhao, Kai Zhang, Licheng Wu, Qian Wang, Danhong Shang, Qin Zhong
Summary: This study evaluates the effect of self-doping Ti3+ into catalysts on the activity of the catalysts. Various characterization methods such as XRD, XPS, and EPR confirm the presence of Ti3+ and oxygen vacancy, which significantly affect the performance of the catalysts. The results indicate potential for improving low-temperature SCR performance through strategic design of Ti3+ self-doped catalysts.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Min-Jae Kim, Jae-Rang Youn, Seung-Jae Lee, In-Soo Ryu, Sung Chan Nam, Soon Kwan Jeong, Sang Goo Jeon
Summary: In this study, the surface properties and performance of CeO2-promoted Mn/TiO2 catalysts in the low-temperature selective catalytic reduction (SCR) of NO by NH3 were investigated by changing the impregnation sequence of Mn and Ce. The results showed that the co-impregnated catalyst had higher NO conversion and improved metal dispersion, providing more adsorption sites. Additionally, the acidity of the catalyst could be controlled by changing the synthesis method.
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
(2022)
Article
Chemistry, Physical
Hyungwon Ham, Hyun Seung Jung, Hyo Seok Kim, Jihyeon Kim, Sung June Cho, Won Bo Lee, Myung-June Park, Jong Wook Bae
Article
Nanoscience & Nanotechnology
Su-Kyung Lee, Hongjun Park, Ji Woong Yoon, Kiwoong Kim, Sung June Cho, Guillaume Maurin, Ryong Ryoo, Jong-San Chang
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Chemistry, Applied
Min Sik Kim, Ki Hun Park, Sung June Cho, Eun Duck Park
Summary: The study found that the catalyst preparation method has a significant impact on the catalytic activity of Fe-ZSM-5 for the partial oxidation of methane with H2O2 in an aqueous phase. The aqueous phase ion-exchange method demonstrated the best results, producing isolated or oligonuclear extra-framework Fe species with the highest catalytic activity.
Article
Chemistry, Physical
Inhak Song, Hwangho Lee, Se Won Jeon, Do Heui Kim
Article
Multidisciplinary Sciences
Inhak Song, Hwangho Lee, Se Won Jeon, Ismail A. M. Ibrahim, Joonwoo Kim, Youngchul Byun, Dong Jun Koh, Jeong Woo Han, Do Heui Kim
Summary: This study demonstrates that physically mixed H-Y zeolite can protect vanadium active sites effectively by trapping ABS in micropores, enabling the catalyst to operate stably at low temperatures and maintaining sulfur resistance during repeated aging/regeneration cycles. The pore structure and framework Al content of different zeolites play a crucial role in determining the trapping ability.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Hwangho Lee, Inhak Song, Se Won Jeon, Do Heui Kim
Summary: The study aims to reveal the mobility-dependent SCR reaction by controlling Cu species with different ion mobilities in Cu-SSZ-13. The results indicate that enhanced ion mobility leads to improved NH3-SCR activity, providing insights for designing rational catalysts by tuning ion mobility.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Environmental Sciences
Se Won Jeon, Inhak Song, Hwangho Lee, Do Heui Kim
Summary: Vanadium oxide-based catalysts, such as V/MPTiO2, are promising for SCR of NO with NH3. Addition of W and Mo as promoters to V/MPTiO2 can enhance deNO(x) activities at low temperatures, while Sb tends to have a negative effect on SCR activity. The addition of W and Mo increases the polymerization in V/MPTiO2, generating more reactive vanadia species and leading to enhanced catalytic activity at low temperatures.
Article
Chemistry, Physical
Inhak Song, Konstantin Khivantsev, Yong Wang, Janos Szanyi
Summary: Pd-ion-exchanged zeolites have emerged as promising materials for the adsorption and oxidation of air pollutants. The researchers found that CO molecules can act as additional ligands to accelerate the adsorption of NO on hydrated Pd ions. They also demonstrated that hydration of Pd ions is a prerequisite for the reduction of Pd ions to metallic Pd by CO. These findings have important implications for understanding and applying the NOx adsorption chemistry in zeolite-based adsorbers.
JOURNAL OF PHYSICAL CHEMISTRY C
(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
Inhak Song, Konstantin Khivantsev, Yiqing Wu, Mark Bowden, Yong Wang, Janos Szanyi
Summary: Moisture facilitates the storage of NO on hydrated Pd ions in high temperature calcined zeolites and can be released during dehydration. The relocation of Pd ions to more stable cationic positions is responsible for this behavior.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2022)
Article
Chemistry, Multidisciplinary
Konstantin Khivantsev, Nicholas R. Jaegers, Hristiyan A. Aleksandrov, Inhak Song, Xavier Isidro Pereira-Hernandez, Mark H. Engelhard, Jinshu Tian, Linxiao Chen, Debora Motta Meira, Libor Kovarik, Georgi N. Vayssilov, Yong Wang, Janos Szanyi
Summary: Atom trapping leads to catalysts with atomically dispersed Ru1O5 sites on (100) facets of ceria, showing excellent activity in catalytic NO oxidation and high NOx storage properties. The Ru1O5 sites exhibit higher stability during calcination and the Ru1/CeO2 catalyst is stable during continuous cycling and in the presence of moisture. In addition, the catalyst shows excellent reactivity for NO reduction by CO at low temperatures. This study highlights the applicability of novel ceria-based single-atom catalysts in NO and CO abatement.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Hwangho Lee, Inhak Song, Se Won Jeon, Keon Ha Hwang, Do Heui Kim
Summary: This paper proposes an innovative regeneration strategy to recover the activity of sulfur-poisoned catalysts by dissolving ammonium bisulfate in the adsorbed water.
APPLIED CATALYSIS B-ENVIRONMENT AND ENERGY
(2024)
Article
Chemistry, Physical
Hwangho Lee, Jonghyun Kim, Inhak Song, Se Won Jeon, Sung June Cho, Do Heui Kim
Summary: In this study, a seed-assisted strategy was used to modulate the Al distribution in a KFI-type zeolite, resulting in improved activity for the NH3-SCR reaction. By altering the Al distribution, the proportion of paired Al sites was increased, leading to different coordination environments and enhanced proximity among Cu ions. The seed-assisted Cu-KFI catalysts showed superior intrinsic NH3-SCR activity, especially at low temperatures (200-250 degrees C), due to the regulated cation-framework interactions.
CATALYSIS SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Physical
Hwangho Lee, Inhak Song, Se Won Jeon, Do Heui Kim
Summary: By introducing Co2+ co-cations onto Cu-SSZ-13 catalyst, the reactivity of CuCo-SSZ-13 catalyst can be enhanced, demonstrating higher SCR reactivity compared to conventional Cu-SSZ-13 catalyst under both low- and high-temperature conditions.
CATALYSIS SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Multidisciplinary
Inhak Song, Hwangho Lee, Se Won Jeon, Taejin Kim, Do Heui Kim
CHEMICAL COMMUNICATIONS
(2020)
