FUEL
·
2022
·
IF 8.035
Xiaodi Li,Shan Ren,Lian Liu,Xiangdong Xing,Lin Chen,Jiangling Li,Jian Yang,Qingcai Liu
The serious deactivation of denitration catalysts caused by heavy metals still a thorny issue in the practical application of selective catalytic reduction of NO x with NH 3 . Herein, we proposed a novel anti-poisoning strategy by designing SO 4 2− /ZrO 2 superacid supported CeO 2 /ZrO 2 catalyst, and the effect of SO 4 2− /ZrO 2 supported CeO 2 /ZrO 2 for PbO-resistance NO x catalytic reduction was investigated. It was worthy to note that the introduction of solid superacid SO 4 2− /ZrO 2 significantly enhanced catalytic performance over the entire temperature range, with an exceptionally high NO x removal efficiency over 98 % during 250–500 °C. When 2 wt% PbO was deposited on the fresh catalyst, the catalytic activity of CeO 2 /ZrO 2 catalyst decreased obviously, while CeO 2 /ZrO 2 -S catalyst can still maintain a higher NO x conversion over 90 % from 275 to 500 °C. The characterization results confirmed that the introduction of solid superacid SO 4 2− /ZrO 2 enhanced the surface acidity and promoted the transformation from Ce 4+ to Ce 3+ . The results of in situ DRIFTS implied that the Eley-Rideal (E-R) mechanism was obeyed over CeO 2 /ZrO 2 catalyst, and both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms were followed over CeO 2 /ZrO 2 -S catalyst in the SCR process. With regard to poisoned catalysts, the NH 3 adsorption was inhibited to some extent, while the reaction mechanism wasn’t changed by PbO poisoning.
研究领域:
催化
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
En-Hui Yuan,Meng Li,Ming-Hui Yang,Xiaosheng Huang,Kun Zhang,Weiliang Han,Zhicheng Tang,Zhong-Wen Liu
A direct hydrothermal synthesis strategy is developed to prepare the Cu–Fe-ZSM-5 zeolites by using the ethylenediaminetetraacetic acid disodium dihydrate (EDTA-2Na·2H 2 O) chelated Cu 2+ and Fe 3+ precursors as metal sources. During the crystallization, the metal chelates were spontaneously embedded into the ZSM-5 crystals and subsequently transformed to the zeolites encapsulated copper and iron species after removing the chelating agent via the high-temperature calcination . Rigorous characterizations indicate that the resulted Cu 2+ /Cu + and Fe 3+ /Fe 2+ species are formed ultra-small nano-composites with an average diameter of ∼2.2 nm and highly dispersed in the ZSM-5 zeolite crystals. The acidity of the ZSM-5 zeolites is subtly modulated by the encapsulated Cu–Fe nano-composite. As expected, the as-prepared Cu–Fe-ZSM-5 exhibits outstanding catalytic performance for the selective catalytic reduction of NO x with ammonia (NH 3 -SCR) in the broad reaction temperature ranges of 220–480 °C, which is much better than the Cu–Fe/ZSM-5 prepared with the conventional wetness impregnation method. Furthermore, the resultant zeolites show high stability and good tolerance to H 2 O and SO 2 , and it is very competitive for practical application to eliminate NO x . The developed one-pot hydrothermal synthesis route by using EDTA-2Na·2H 2 O as chelating agent is very convenient and easily reproducible, providing a general guideline to design and fabricate the superior transition metal modified zeolite catalysts for NH 3 -SCR and the related reactions.
研究领域:
催化
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ACS Nano
·
2021
·
IF 15.881
Jingjie Wu,Xianli Li,Xin Lian,Binbin Su,Junhong Pang,Ming-De Li,Zhiguo Xia,Jin Z. Zhang,Binbin Luo,Xiao-Chun Huang
Antimony-based metal halide hybrids have attracted enormous attention due to the stereoactive 5s2 electron pair that drives intense triplet broadband emission. However, energy/charge transfer has been rarely achieved for Sb3+-doped materials. Herein, Sb3+ ions are homogeneously doped into 2D [NH3(CH2)4NH3]CdBr4 perovskite (Cd-PVK) using a wet-chemical method. Compared to the weak singlet exciton emission of Cd-PVK at 380 nm, 0.01% Sb3+-doped Cd-PVK exhibits intense triplet emission located at 640 nm with a near-unity quantum yield. Further increasing the doping concentration of Sb3+ completely quenches singlet exciton emission of Cd-PVK, concurrently with enhanced Sb3+ triplet emission. Delayed luminescence and femtosecond-transient absorption studies suggest that Sb3+ emission originates from exciton transfer (ET) from Cd-PVK host to Sb3+ dopant, while such ET cannot occur with Pb2+-doped Cd-PVK because of the mismatch of energy levels. In addition, density function theory calculations indicate that the introduced Sb3+ likely replace the Cd2+ ions along with the deprotonation of butanediammonium for charge balance, instead of generating Cd2+ vacancies. This work provides a deeper understanding of the ET of Sb3+-doped Cd-PVK and suggests an effective strategy to achieve efficient triplet Sb3+ emission beyond 0D Cl-based hybrids.
研究领域:
材料科学
·
光电学
·
化学
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Hanzi Liu,Changfu You,Haiming Wang
Transient in-situ IR spectroscopy was performed to analyze the molecular behavior of selective catalytic reduction of NO with NH 3 on V 2 O 5 -WO 3 /TiO 2 catalyst. During NH 3 adsorption, an unexpected growth in the intensity of Lewis acid sites was observed due to the hydrogen migration, which was verified by the DFT calculation and the existence of intermediate species. The comparison between the isolated atmosphere experiments and the simultaneous exposure of NH 3 -NO-O 2 on catalytic monolayer demonstrated that: (i) there exists a pathway for Lewis to Brønsted acid sites transformation at T > 300 °C, (ii) the rate determining step of the SCR cycle involves in the re-oxidation of acid sites by O 2 at 200–300 °C. Generally, the Lewis acids are crucial at high temperatures, while Brønsted acids dominate the overall reaction at lower temperatures. Based on the experimental data and the DFT calculation, a mechanism for ammonia adsorption, acidity conversion and re-oxidation for the redox loop of the de-NOx reaction was proposed. The findings shed light on the understanding of relative strength of NO reduction and acid re-oxidation at different temperatures.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Xiaofeng Wang,Zhe Zhao,Yang Xu,Qingbo Li
A series of 3DOM-Mn x Ce y Ti z catalysts with three-dimensionally ordered macroporous (3DOM) structure were synthesized by a soft template method. The high SCR activity of the 3DOM-Mn 3 Ce 1 catalyst at low temperature was owing to the excellent redox ability and rich Lewis and Brønsted acid sites of the catalysts, which were beneficial to improve the catalytic activity. However, the strong oxidizability of MnO x resulted in the nonselective oxidation of NH 3 and generation of N 2 O, decreasing the N 2 selectivity. After addition of Ti, the redox capacity of the 3DOM-Mn 3 Ce 1 Ti 1 catalyst decreased, and the NH 3 were strongly adsorbed on the acid sites, which enhanced the N 2 selectivity with a broadened temperature window of 240–440 °C and a high GHSV of 120000 h −1 . Furthermore, both the 3DOM-Mn 3 Ce 1 and 3DOM-Mn 3 Ce 1 Ti 1 catalysts showed remarkable tolerance of H 2 O. Finally, through in situ DRIFT analysis, the Langmuir-Hinshelwood (L-H) mechanism was confirmed as the dominant reaction pathway over the 3DOM-Mn 3 Ce 1 Ti 1 catalyst.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2025
·
IF 17.7
Ye Wang,Pan Gao,Dan Zhao,Tongrui Liu,Sitong Zhou,Miao Yang,Shiping Liu,Bing Li,Yida Zhou,Wenhao Cui,Guangjin Hou,Peng Tian,Zhongmin Liu
Silicoaluminophosphate (SAPO) molecular sieves possess diverse architectures and exceptional high-temperature hydrothermal stability, rendering them important acid catalysts. However, enhancing acid concentration of certain SAPO materials remains challenging, which limits their catalytic applications. Here, we report the synthesis of a series of SAPO materials using a developed SAPO precursor plus dual template (SPDT) strategy. A variety of SAPO materials characterized by high silica content and enhanced acidity, such as SAPO-34/56 intergrowths, SAPO-56, and SAPO-17, have been synthesized and thoroughly characterized using various techniques including integrated differential phase-contrast scanning transmission electron microscopy, two-dimensional solid-state nuclear magnetic resonance spectroscopy, and continuous rotation electron diffraction. The use of silica-enriched SAPO precursor combined with the flexible selection of the second template enables the crystalline phase regulation and improves the Si atoms incorporation into the framework. Notably, the synthesized SAPO-17 with abundant Si(4Al) species and unprecedentedly high acid density exhibits exceptional DeNO x activity after Cu loading, with NO x conversion exceeding 90% at 175–700 °C. This outstanding performance can be attributed to the unique ERI structure and the increased acidity of SAPO-17. This work not only presents an effective method for synthesizing SAPO molecular sieves with enhanced acidity but also offers a new perspective for expanding the active temperature range of the ammonia selective catalytic reduction reaction.
研究领域:
材料化学
·
催化化学
·
无机非金属材料
·
环境催化
·
分子筛科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2023
·
IF 12.9
Yanfei Liu,Zhang Liu,Chengxiong Wang,Jie Xu,Jianping Ai,Xiao Liu,Aimin Zhang,Yunkun Zhao,Chun Du,Bin Shan
Supported Pt catalysts suffer from low reaction selectivity (<65% at 100% conversion) in the selective catalytic oxidation of ammonia (NH3-SCO) because of their intrinsic over-oxidation tendencies. Herein, a strategy based on facilitating byproduct NOx reduction to N2 is demonstrated at CuOx/PtCu catalysts, aiming to tackle the low selectivity challenge. This PtCu alloy sample with a CuOx-rich surface displays an N2 selectivity of 95%, while its turnover frequencies are the highest among reported supported Pt-based catalysts. The enhanced reaction activities and N2 selectivities are primarily attributed to the Pt-Cuδ+ dual-site synergies at the CuOx/PtCu interface, in which dual sites exhibit distinct NH3 adsorption, activation, and dehydrogenation behaviors. The Olat assisted internal selective catalytic reduction mechanism at CuOx/PtCu with N2O22– as the central intermediates is proposed. Density functional theory calculation and temperature-programmed surface reaction measurements show that the N–O bond in N2O22– tends to break simultaneously with the assistance of Ov in CuOx followed by the easy transition from N2O22– to N2, which serve as the origin of the high selectivity.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Chengzhi Wang,Fengyu Gao,Songjin Ko,Hengheng Liu,Honghong Yi,Xiaolong Tang
The presence of SO 2 in industrial flue gases will cause permanent deactivation of the catalyst active centre. Therefore, an effective method to improve the SO 2 resistance of manganese-based catalysts at low temperatures is urgently needed. In this work, a hierarchical porous nanowire structure catalyst was designed by the in situ self-assembly method to inhibit SO 2 adsorption. This hierarchical porous nanowire aerogel catalyst with great BET surface area and surface acidity exhibited NOx conversion above 90% at 100–400 °C. Notably, the NOx conversion of the MnCe-N catalyst was almost not inhibited by SO 2 (250 ppm) compared to the 33% decrease of the MnCe-P catalyst. On the MnCe-P catalyst, SO 2 has strong competitive adsorption with NH 3 and NO, and the stronger adsorption capacity of SO 2 inhibits the adsorption activation of the reaction gas and hinders the reaction proceeding through the L-H mechanism. Meanwhile, a large quantity of sulfate is formed on the catalyst surface, which prevents the active centre to participate in the redox reaction. The structure of nanowires enhances the number of acid sites, facilitates the adsorption and activation of NH 3 , and effectively inhibits the adsorption of SO 2 on the MnCe-N catalyst. Fewer sulfate species are generated and difficult to deposit and aggregate on the catalyst surface, as a result, the active centre is less affected by sulfate species. The stable adsorption of NH 3 -related species ensures reliable reaction on MnCe-N through the E-R mechanism. This work emphasizes the importance of hierarchically porous structures in improving the NH 3 -SCR performance and SO 2 resistance of monolithic catalysts, and provides new insights into the design of highly efficient and stable catalytic materials.
研究领域:
催化
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2024
·
IF 5.5
Daming Feng,Lixue Zhou,Chang Liu,Hui Li,Yusheng Zhang,Yali Yao,Tianyi Ma
Electrocatalytic nitrogen reduction reaction (NRR) for the synthesis of ammonia (NH 3 ) is one of the green and mild methods of artificial nitrogen fixation, promising as an alternative to replace the existing industrial process. Under the requirements of green chemistry and sustainable development, the design and development of highly active and stable electrocatalysts is very important for improved synthesis performance. Mimicking from the natural nitrogenase, Fe and Mo based catalysts have attracted much attention due to their superior catalytic performance for N 2 adsorption and activation. In this work, an interfacial engineering strategy has been used to prepare a Fe, Mo-bimetallic electrocatalyst for the electrosynthesis of NH 3 . In detail, the pre-pyrolyzed biochar-based Fe 2 O 3 composites were decorated with nano-flowered MoS 2 /MoO 2 hybrids by a solvothermal process (MoS 2 /MoO 2 @Fe 2 O 3 /BC). As confirmed by the extensive characterization, the further modification not only introduced functional counterparts into the electrocatalysts but also regulated the morphology of the nanostructure. The electrochemical tests showed that the highest NH 3 yield rate of MoS 2 /MoO 2 @Fe 2 O 3 /BC was 4.87 μg h − 1 cm −2 and highest FE was 16.5% in 0.1 M Na 2 SO 4 . The catalytic stability and durability were also presented in the longtime electrolysis and cycling experiments. The improved catalytic performance of decorated catalyst, as evidenced by the comparison with Fe 2 O 3 /BC, is attributed to the increased electrocatalytic active area, the moderated hydrophilicity, and the synergistic effect of Fe, Mo-bimetallic active sites. This study provides a new perspective for the design and development of low-cost transition metal complexes as electrocatalysts for nitrogen reduction reactions.
研究领域:
电化学
·
催化
·
材料科学
·
环境化学
·
可持续能源
✓ 已验证
产品关联
DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2025
·
IF 3.5
Li Xinyu,Li Jingqi,Li Na
This study investigated the effects of sequential acid treatment and phosphorus incorporation on the performance of Fe–Mn-Ce composite metal oxide catalysts. The FeMnCeO x catalyst was prepared using the sol–gel method and modified through two methods: treatment with phosphoric acid alone and a sequential treatment with phosphoric acid followed by sulfuric acid. The results show that the sequentially acid-treated catalyst exhibited over 90% NO x conversion and N 2 selectivity in the temperature range of 200–350 °C, outperforming other catalysts. Characterization analyses such as XRD and NH 3 -TPD revealed that acid modification enhanced the surface acidity and redox properties of catalysts. XPS analysis showed that sequential acid treatment increased the surface chemisorbed oxygen content of the catalyst and optimized its surface structure. In-situ DRIFTS spectroscopy further elucidated that the catalytic reaction follows both Langmuir–Hinshelwood and Eley–Rideal mechanisms concurrently.
研究领域:
环境科学
·
催化化学
·
材料科学
·
化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Ling Ouyang,Qiang Zhou,Jie Liang,Longcheng Zhang,Luchao Yue,Zerong Li,Jun Li,Yongsong Luo,Qian Liu,Na Li,Bo Tang,Abdulmohsen Ali Alshehri,Feng Gong,Xuping Sun
Electrocatalytic NO reduction is a promising technology for ambient NO removal with simultaneous production of highly value-added NH 3 . Herein, we report that honeycomb carbon nanofiber coated on carbon paper acts as an efficient metal-free catalyst for ambient electroreduction of NO to NH 3 . In 0.2 M Na 2 SO 4 solution, such catalyst achieves an NH 3 yield of 22.35 μmol h −1 cm −2 with a high Faradaic efficiency of up to 88.33%. Impressively, it also shows excellent stability for 10-h continuous electrolysis. Theoretical calculations reveal that the most active center of functional groups is –OH group for NO reduction with a low energy barrier (ΔG of 0.29 eV) for the potential-determining step (*NO + H → *HNO).
研究领域:
环境科学
·
材料科学
·
电化学
·
催化
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2024
·
IF 4.4
Zhicheng Xu,Jin Xiong,Yuran Li,Junxiang Guo,Bin Wang,Tingyu Zhu
For industrial flue gas purification at medium and low temperatures, it is highly necessary to promote the denitrification activity of V-based catalysts in a SO2 atmosphere. Transition metals (Ce, Co, Fe, and Mn) are used to modify V/Ti catalysts to improve SO2 resistance with ammonium bisulfate deposition on the catalysts. Sulfation on Ce with less ammonium bisulfate deposition considerably improves the SO2 resistance of V1Ce5/Ti, and stable sulfation on TiO2 promoted by Co provides additional Brønsted acid sites for V1Co5/Ti to reduce the deactivation. Serious sulfation on V1Mn5/Ti with large ammonium bisulfate deposition on V1Fe5/Ti causes deeper deactivation. The formation mechanism of ammonium bisulfate on active metal sites and TiO2 carriers has been clarified. SO2 is adsorbed on V sites and transition metal sites followed by oxidation and ammoniation or adsorbed on TiO2 carriers followed by ammoniation and oxidation. The first pathway is more dominant than the second pathway in the presence of O2 with the co-oxidation of SO2 by O2 and lattice oxygen. The initial formation temperature and stable temperature of dominant intermediates were determined by in situ DRIFTS. SO2 adsorbed on TiO2 carriers is oxidized by V sites above 170 °C to form a tridentate sulfate, while SO2 adsorbed on transition metal sites is initially oxidized by transition metal sites above 50 °C to form monodentate and bidentate sulfates, as well as competitively oxidized by V sites above 170 °C to form tridentate sulfates. The selective adsorption of SO2 on transition metal sites or TiO2 carriers and the competitive oxidation of SO2 by transition metal sites and V sites provide a synergistic effect between V sites and transition metal sites to reduce ammonium sulfate deposition and release more active sites. These findings provide theoretical guidance to design and prepare V-based catalysts with high denitrification activity in the presence of SO2.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）