Article
Chemistry, Multidisciplinary
Chenglong Li, Zhitao Han, Xinxin Wang, Yu Gao, Zhen Wang, Xinxiang Pan
Summary: This study investigates the effect of sulfuric acid treatment on the Ca resistance of CeO2 catalysts supported by ZrO2. The results demonstrate that the CeO2/ZrO2-S catalyst displays significantly better SCR activity and Ca resistance compared to the CeO2/ZrO2 catalyst. Characterization techniques such as BET, XRD, Raman, XPS, H-2-TPR, NH3-TPD, and in situ DRIFTS were employed to analyze the changes in structure and properties of the catalysts before and after Ca deactivation tests. The results indicate that the Ca poisoning in CeO2/ZrO2 catalysts is mainly caused by the decrease in surface area and acidity, loss of reducibility, and enhanced stabilization of adsorbed nitrate/nitrite species. The treatment of ZrO2 with sulfuric acid leads to an increase in surface area, highly-dispersed Ce species, inhibition of tetragonal to monoclinic phase transformation, improved redox properties, Ce3+ species ratio, total surface acidity (especially Bronsted acid sites), and adsorption of NH3 species. Furthermore, the SCR reactions via both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms can still proceed effectively even after Ca poisoning in the CeO2/ZrO2-S catalysts.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Environmental Sciences
Yijuan Pu, Pengchen Wang, Wenju Jiang, Zhongde Dai, Lin Yang, Xia Jiang, Zhicheng Jiang, Lu Yao
Summary: The newly prepared CeO2/CNTs-GAC catalyst exhibits high efficiency in low-temperature selective catalytic reduction of NOx by NH3 and excellent SO2 resistance. The addition of CNTs enhances the catalytic performance, inhibits SO2 adsorption, and promotes the formation of oxygen oxidation species.
Article
Engineering, Environmental
Ruiyang Chen, Xiaoyu Fang, Junhua Li, Yi Zhang, Zhiming Liu
Summary: In this study, a novel MnCoOx sphere catalyst with high activity and remarkable SO2 tolerance was developed. The mechanism of SO2 poisoning of pure MnOx catalyst was revealed, and it was found that MnCoOx catalyst can maintain high catalytic performance in the presence of SO2.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
Xiaoxiong Fan, Lifang Hao, Xiangyu Gu, Songgeng Li
Summary: In this study, a modified biochar-supported perovskite oxide catalyst was synthesized to achieve high denitration efficiency for selective catalytic reduction with ammonia (NH3-SCR) at low temperatures. Different modification methods were compared, and it was found that the combination of nitric acid and air oxidation treatment provided a biochar support with abundant acidic surface oxygen-containing groups and a higher specific surface area. The LaMnO3/biochar catalyst exhibited excellent denitration efficiency and good N2 selectivity, achieving over 80% NO conversion within the entire temperature range of 100-250 degrees C. The catalyst provided synergistic adsorption capacity for NH3 through the acidic function of perovskite oxide and modified biochar support, and LaMnO3 showed a strong redox capability for NO conversion due to the high content of Mn4+ and chemically adsorbed oxygen species. The NH3-SCR reaction mechanisms were proposed based on transient response experiments and in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) characterization.
Article
Chemistry, Physical
Shiyu Xu, Jiawei Chen, Zhenguo Li, Zhiming Liu
Summary: MnOx catalysts with 3D structure (Mn-HT) were prepared using KIT-6 as a template by the hard-template method, and their catalytic performance for the selective catalytic reduction of NOx by NH3 was investigated at low temperatures. It was found that the template KIT-6 prepared at different hydrothermal temperatures significantly affected the catalytic performance of Mn-HT catalysts. Among them, Mn-140 catalyst prepared using the template obtained at a hydrothermal temperature of 140 degrees C exhibited the highest catalytic performance. Characterizations showed that Mn-140 catalyst possessed high reducibility with abundant surface oxygen species and Mn4+ species. NH3-TPD and in situ DRIFTS demonstrated that there were more Lewis acid sites and Bronsted acid sites on the surface of Mn-140 catalyst, promoting the adsorption and activation of NH3 and efficiently reducing NOx mainly by the Eley-Rideal (E-R) mechanism, accompanied by the Langmuir-Hinshelwood (L-H) mechanism.
APPLIED CATALYSIS A-GENERAL
(2023)
Article
Chemistry, Multidisciplinary
Chenglong Li, Zhitao Han, Yuqing Hu, Tingjun Liu, Xinxiang Pan
Summary: In this study, a series of tungsten-zirconium mixed binary oxides were synthesized as supports for Ce-0.4/WmZrOx catalysts. The promoting effect of W doping on the SCR performance of Ce-0.4/ZrO2 catalysts was investigated. The results showed that proper W doping significantly enhanced the catalytic performance and SO2 tolerance of Ce-0.4/ZrO2 catalysts.
Article
Energy & Fuels
Ben Wang, Zhongpeng Wang, Zhuo Yang, Huafang Li, Hui Sheng, Wei Liu, Qian Li, Liguo Wang
Summary: A series of novel highly dispersed MnOx on the MgAlOx support were prepared and exhibited superior low-temperature selective catalytic reduction of NOx performance as well as remarkable resistance against H2O. The MgAlOx support provided large specific area for the dispersion of Mn and more adsorption sites for reactant molecules.
Article
Chemistry, Physical
Jingjing Liu, Xiaoyan Shi, Yunbo Yu, Mengyuan Zhang, Diru Liu, Hong He
Summary: The HC resistance of CeWSnOx, V2O5-WO3/TiO2, and Cu-SSZ-13 catalysts was studied using propene, toluene, and n-pentane as model HCs. The CeWSnOx catalyst showed much better HC tolerance due to its strong HC oxidation capacity, which inhibited side reactions. In contrast, Cu-SSZ-13 and V2O5-WO3/TiO2 showed undesired HC ammoxidation reactions, especially in the presence of propene.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Engineering, Chemical
Lin Chen, Shan Ren, Yuhan Zhou, Xiaodi Li, Mingming Wang, Zhichao Chen, Jie Yang
Summary: Transition metal oxides impregnated on nanopolyhedron CeO2 catalysts showed that Mn-CeO2-NP catalyst exhibited the highest NOx conversion in SCR reaction, with higher oxygen vacancy concentration and more acid sites.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2022)
Article
Engineering, Environmental
Xiaodi Li, Shan Ren, Xiangdong Xing, Yanhua Jiang, Lin Chen, Lian Liu, Jiangling Li, Jian Yang, Qingcai Liu
Summary: This study investigated the effects of MoO3 and WO3 on the selective catalytic reduction performance of Fe/Zr catalyst. It was found that WO3 might promote the catalytic activity by improving the redox property and surface acidity.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2022)
Article
Chemistry, Physical
Wenshuo Hu, Federica Gramigni, Nicole Daniela Nasello, Nicola Usberti, Umberto Iacobone, Shaojun Liu, Isabella Nova, Xiang Gao, Enrico Tronconi
Summary: Cu-exchanged chabazite zeolite (Cu-CHA) is an efficient catalyst for the selective catalytic reduction (SCR) of NOx, and the dynamic cycling of Cu cations plays an important role in the SCR process. Cu cations are activated by forming Cu-NH3 complexes through reaction with NH3 under low-temperature conditions, and they exhibit homogeneous features in the heterogeneous catalytic process of low-temperature SCR. These features are influenced by electrostatic interactions between Cu cations and conjugate Al centers.
Article
Energy & Fuels
Yuhan Zhou, Shan Ren, Mingming Wang, Jie Yang, Zhichao Chen, Lin Chen
Summary: The research shows that loading manganese and iron oxide active components on the surface of CeO2 nanopolyhedrons catalyst can significantly improve its low temperature SCR performance. The Fe-Mn-Ce catalyst exhibits the highest NO conversion rate and best reducibility and surface acidity among the catalysts tested.
JOURNAL OF THE ENERGY INSTITUTE
(2021)
Article
Chemistry, Physical
Huanyu Zhao, Jinwei Luo, Wei Tang, Baozhen Li, Ang Li, Dongxue Zhou, Ying Ou, Changmin Hou
Summary: In this study, CeO2 @TiO2 catalysts were prepared by encapsulating Ce ions into MIL-125 channels and annealing the Ce/MIL-125 precursor. The CeO2 @TiO2 catalysts had a NO conversion of nearly 100% at 350 degrees C and a wide temperature range larger than 200 degrees C, attributed to the high dispersion of CeO2 in the composites and the porous structure of CeO2 @TiO2 (2/3) catalyst, which exhibited high specific surface area. Furthermore, the CeO2 @TiO2 (2/3) catalyst had excellent NH3-SCR properties with a wide temperature range (200 degrees C to 450 degrees C) and outstanding resistance to H2O and SO2, thanks to the presence of Ce3+ sites, enriched surface oxygen species, effective adsorption of NOx species, and high surface acidity.
APPLIED CATALYSIS A-GENERAL
(2023)
Article
Chemistry, Physical
Ming Cai, Xue Bian, Feng Xie, Wenyuan Wu, Peng Cen
Summary: The addition of PEO significantly affects the physical and chemical properties of the CeO2-WO3/TiO2 catalysts, improving their catalytic activity. PEO not only optimizes the pore structure of the catalysts but also enhances their adsorption and redox abilities.
Article
Engineering, Environmental
Jie Zhang, Yixuan Fan, Liqiu Chen, Lixia Yang, Lei Zhou, Xubiao Luo, Jianping Zou, Weili Dai
Summary: CeO2-based oxides doped with Ti exhibit enhanced catalytic performance and SO2 resistance for low-temperature selective catalytic reduction of NOx.
CHEMICAL ENGINEERING JOURNAL
(2023)
