Article
Chemistry, Physical
Yusuke Inomata, Hiroe Kubota, Yoshinori Honmatsu, Hiroaki Takamitsu, Sosuke Sakotami, Kazuhiro Yoshida, Takashi Toyao, Ken-ichi Shimizu, Toru Murayama
Summary: NH3-SCR is a key technique for reducing harmful NOx emissions. The study shows that Na-intercalated vanadium oxide can accelerate the reaction and improve the efficiency of NH3-SCR.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Engineering, Chemical
Piqiang Tan, Xiaoyu Li, Shiyan Wang, Zhiyuan Hu, Diming Lou
Summary: In this study, the failure of SCR due to a low NH3-NOx ratio was systematically investigated through experiments, with major causes including insufficient urea injection, catalyst hydrothermal aging, and urea crystallization. The NOx conversion efficiency in the SCR system was found to increase with higher NH3-NOx ratio, but with an increase in ammonia leakage. Different factors influenced NOx conversion efficiency under different NH3-NOx ratios.
CHINESE JOURNAL OF CHEMICAL ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Marc Magre, Josep Cornella
Summary: A bi-catalyzed synthesis of sulfonyl fluorides from (hetero)aryl boronic acids is demonstrated using organobismuth(III) catalysts, resulting in excellent yields and wide functional group tolerance. The catalytic cycle involves various organometallic steps without changing the oxidation state, forming a structurally unique bismuth sulfinate complex.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Engineering, Environmental
Shuang Chen, YeJia Lv, Jiaxing Hong, Luman Hou, Jia Zhang, Xiaoqiao Zhang, Xiangyu Zhao, Lixin Wang, Guangren Qian
Summary: Developing a more effective catalyst for environmental pollutants is a global research pursuit. Previous studies focused on prepared catalysts, but more efforts should explore the process from precursor to formed catalyst. In this work, V supported TiO2 catalysts with different V loadings were synthesized and compared for selective catalytic reduction of nitrogen oxide. Differential scanning calorimetry was used for the first time to analyze the forming enthalpy of these catalysts. The results showed that single-atom V had a higher formation enthalpy, lower dehydrogenation energy, and larger turnover frequency (TOF) than cluster V. These findings help optimize the preparation process for an effective catalyst, benefiting hazardous pollutant treatment.
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
(2023)
Article
Chemistry, Physical
Hongyan Xue, Xiaoming Guo, Dongsen Mao, Tao Meng, Jun Yu, Zhen Ma
Summary: In this study, H3PW12O40-modified MnOx catalysts (Mn-HPW) were used for NOx elimination with co-fed NH3. The optimal Mn-HPW0.02 catalyst exhibited over 90% NOx conversion at 90-270 degrees C. The incorporation of HPW increased the amount of Lewis acid sites of the catalyst, facilitating the reaction between NH3 and NOx and enhancing the low-temperature catalytic activity. The addition of HPW also mitigated overoxidation and improved the selectivity in the high-temperature region.
Article
Chemistry, Multidisciplinary
Anqi Dong, Zhi Yang, Weichao Wang
Summary: This study successfully achieved low-temperature NH3 oxidation by synthesizing mixed-phase catalysts SmMn2O5/Cu-SAPO34. The physicochemical properties of the catalysts were analyzed using characterization methods, and it was found that the internal SCR mechanism is the main reason for the improved conversion and selectivity.
Article
Energy & Fuels
Xiaofeng Wang, Yang Xu, Zhe Zhao, Jianbin Liao, Chen Chen, Qingbo Li
Summary: This review summarizes the development of zeolite catalysts in the SCR reaction, including Cu, Fe, Mn and other metal-exchanged zeolites. The study discusses the active sites of different metal-exchanged zeolites in NH3-SCR reaction, emphasizes the role of second metals and metal oxides, and effects of preparation methods and topologies. Challenges and further perspectives of metal-exchanged zeolites in NH3-SCR reaction are proposed to enhance the efficiency of NOx removal.
Article
Chemistry, Physical
Jinpeng Du, Yulong Shan, Yu Sun, Meng Gao, Zhongqi Liu, Xiaoyan Shi, Yunbo Yu, Hong He
Summary: The study reveals that after hydrothermal aging, Cu-SSZ-39 showed a remarkable increase in low-temperature NH3-SCR catalytic activity, attributed to the transformation of Cu2+ ions into CuxOy species facilitating the production of nitrate species critical for the catalytic process.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
Article
Chemistry, Physical
Jingjing Liu, Guangzhi He, Wenpo Shan, Yunbo Yu, Yanlong Huo, Yan Zhang, Meng Wang, Rong Yu, Shengsheng Liu, Hong He
Summary: In this study, a Ce1W0.24Sn2Ox catalyst with high hydrothermal stability was synthesized for NOx removal from diesel engines, showing excellent performance. The experimental results demonstrate that the catalyst exhibits outstanding sintering resistance and provides sufficient active phase for catalytic reaction.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2021)
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
Liwei Sun, Peng Liu, Jianheng Xu, Kaijie Liu, Zeshu Zhang, Yibo Zhang, Xiangguang Yang
Summary: In this study, a series of bulk vanadium oxide catalysts were synthesized at different temperatures, and it was found that the catalyst with a large amount of crystalline V2O5 synthesized at low temperatures showed excellent NH3-selective catalytic reduction (NH3-SCR) activity at low temperatures. The role of V4+ species in this catalyst was found to be important for low-temperature NH3-SCR, significantly improving the catalytic performance. The difference in NH3 and O2 activation with different ratios of V4+/V5+ in V2O5 was investigated.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Hui Wang, Shicheng Dong, Yujie Qiao, Zhenping Qu
Summary: CO2 inhibits the NH3-SCR reaction by suppressing the adsorption of NOx on Fe-O-Ce catalyst, reducing the formation of active intermediate species and leading to the deactivation of CO2.
SURFACES AND INTERFACES
(2021)
Review
Chemistry, Applied
Jongsik Kim, Somin Lee, Dong Wook Kwon, Heon Phil Ha
Summary: Rare earth metal vanadates have shown promise for converting NOX to N-2 at high temperatures, but face limitations in catalytic activity due to weak hydrothermal stability, low N-2 selectivity, and limited active sites. This study demonstrates the efficacy of structurally modifying vanadate with additional rare earth metals to generate bimetallic vanadates with improved reactivity and stability.
Article
Engineering, Environmental
Jiangning Liu, Xu Wu, Benhui Hou, Yali Du, Lili Liu, Baoshuan Yang
Summary: The study evaluates NiMn2O4 sphere (NiMn2O4-S) and NiMn2O4 particle (NiMn2O4-P) as catalysts for low temperature NH3-SCR, demonstrating that NiMn2O4-S shows superior catalytic activity mainly through the Eley-Rideal mechanism, attributed to its larger specific surface area contributing to enhanced activity.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2021)
Article
Chemistry, Physical
Dong Ho Kim, Yeon Jae Park, Min Gie Jung, Kwan-Young Lee, Heon Phil Ha, Dong Wook Kwon
Summary: Both V2O5 and MnOx on TiO2 are metal oxides widely used for selective catalytic reduction (SCR) with NH3. The reaction characteristics of SCR were explored by varying the composition of Mn/V. Under NO-rich conditions, the optimal Mn/V ratio resulted in improved performance, while an increase in the amount of Mn compared to V led to an increase in the NOx consumption rate under NO2-rich conditions. The catalysts synthesized according to the Mn/V ratio resulted in changes in the reaction rate and the type of species adsorbed, and followed the Langmuir-Hinshelwood (LH) mechanism for SCR reactions.
APPLIED SURFACE SCIENCE
(2023)