Materials
·
2021
·Vol. 14
·期 20
·5958
·
IF 3.623
Xusheng Ren,Zhiliang Ou,Bang Wu
The activated coke is a promising support for catalysts, and it is important to study the performance of the activated coke catalyst on the removal of NOx. In the current research, a series of the activated coke-supported Mn–Cu catalysts are prepared by the incipient wetness impregnation method. The effects of the molar ration of Mn/Cu, the content of Mn–Cu, the calcination temperature, and reaction space velocity on NO conversion are investigated, and it was found that the 8 wt.% Mn0.7Cu0.3/AC had the best catalytic activity when the calcination temperature was 200 °C. The existence of SO2caused the catalyst to deactivate, but the activity of the poisoning catalyst could be recovered by different regeneration methods. To uncover the underlying mechanism, BET, XPS, XRD, SEM and FTIR characterizations were performed. These results suggested that the specific surface area and total pore volume of the poisoning catalyst are recovered and the sulfite and sulfate on the surface of the poisoning catalysts are removed after water washing regeneration. More importantly, the water washing regeneration returns the value of Mn3+/Mn4+, Cu2+/Cu+, and Oα/Oβ, related to the activity, basically back to the level of the fresh catalyst. Thus, the effect of water washing regeneration is better than thermal regeneration. These results could provide some helpful information for the design and development of the SCR catalysts.Keywords:activated coke;low-temperature NH3-SCR;sulfur poisoning;regeneration
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2021
·
IF 5.565
Weilai Wang,Fan Zhang,Yunfei Zhang,Lei Xu,Yuansheng Pei,Junfeng Niu
Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene (TCE). In this work, the liquid-phase hydrogenation of TCE by Raney Ni (R-Ni) and Pd/C under an open system have been studied, in which nascent H 2 (Nas-H 2 ) generated in situ from the cathode acted as a hydrogen source. Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H 2 bubbles from the cathode. Furthermore, the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated, respectively. The results showed that NO 3 − and acetonitrile can form a competitive reaction with TCE; Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts, and have a stronger inhibitory effect on Pd/C. This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Abubakar Yusuf,Yong Ren,Yun Liu,Li Shi,Zhiyu Xiao,Run Pan,Zheng Wang,Hainam Do,Jianrong Li,Jun He
The efficient treatment of methane emissions from natural gas-powered engines is necessary due to the high potency and global warming potential of methane. Promoters are often employed to enhance catalysts’ performance and stability for methane oxidation. It is therefore important to understand the impact of promoters on Pd activity, especially under practically relevant conditions. Here, we report the enhancement and inhibition effect of promoters (ZrO 2 , CeO 2 , and TiO 2 ) on the sulfur resistance and regeneration of alumina-supported Pd catalysts for complete methane oxidation in the presence and absence of moisture. The type of promoter employed and the presence of moisture influence the type of sulfur species formed on the alumina-supported Pd catalysts, as well as their catalytic performance and regeneration. Whereas ZrO 2 enhances both the activity and SO 2 resistance and enhances the regeneration of the poisoned catalysts under both dry and wet reaction conditions, more stable sulfate species are formed in the presence of CeO 2 and TiO 2 , inhibiting both the catalysts’ performance and regeneration. In addition, the presence of ZrO 2 protects the active Pd sites from progressive deactivation over sulfur poisoning and regeneration cycles. The results of this work provide insights into how promoters influence the activity, sulfur poisoning and regeneration of methane oxidation catalysts in the presence and absence of moisture, which have implications for the practical design of industrially relevant catalysts.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 60
·37787-37796
·
IF 3.108
Xuesong Liu,Xiaodong Wu,Duan Weng,Zhichun Si,Rui Ran
Cu/SAPO-34 catalysts were prepared by wet impregnation and ion-exchange methods, and both the catalysts were hydrothermally treated at 750 °C in 10 vol% H2O/air for 24 h. Subsequently, the as-received and hydrothermally treated catalysts were exposed to a sulfur poisoning treatment at 350 °C in 100 ppm SO2/10 vol% H2O/air for 24 h and examined for NOx conversion. Sulfur poisoning considerably decreased the NOx conversion efficiency of the catalysts at low temperatures. In contrast, it improved the high-temperature selective catalytic reduction (SCR) activities of the as-received catalysts. The ion-exchange-prepared catalysts displayed higher sulfur tolerance than the impregnation-prepared catalysts at 150–350 °C. The electron paramagnetic resonance, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy and H2-temperature-programmed reduction results showed that sulfur poisoning significantly influenced the migration of the copper species and thereby the amount of active isolated Cu2+. More dispersed CuSO4 was produced on the ion-exchange-prepared catalysts than on the impregnation-prepared catalysts after sulfur poisoning. The dispersed CuSO4 showed considerably higher SCR activity than the crystalline CuSO4. Both the dispersed CuSO4 and remaining isolated Cu2+ determined the low-temperature SCR behavior of the sulfur-poisoned catalysts.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 11
·1430
·
IF 4.501
Yang Gao,Li Cao,Xiaodong Wu,Xu Zhang,Ziran Ma,Rui Ran,Zhichun Si,Duan Weng,Baodong Wang
CeNbTi catalyst was poisoned in different sulfur poisoning atmospheres at 300 °C for 6 h and then was evaluated for selective catalytic reduction (SCR) of NOxwith NH3. The catalyst deactivation upon SO2exposure was effectively inhibited in the presence of NH3. Temperature-programmed decomposition (TPD) analyses were applied to identify deposit species on the poisoned catalysts by comparison with several groups of reference samples. Diffuses reflectance infrared Fourier transform spectroscopy (DRIFTS) over CeNbTi catalysts with different poisoning pretreatments and gas purging sequences were designed to investigate the roles of NH3in the removal of surface sulfites and sulfates. More ammonium sulfates including ammonium bisulfate and ammonium cerium sulfate were generated instead of inert cerium sulfate in these conditions. The mechanisms about the formation and transformation of surface deposits upon sulfur poisoning w/wo NH3were explored, which provided a basis for developing Ce-based mixed oxides as SCR catalysts for stationary sources.Keywords:ceria;SCR;sulfur;NH3;TPD;DRIFTS;deposit
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
Catalysis Science & Technology
·
2022
·Vol. 12
·期 11
·3670-3684
·
IF 6.177
Chunwang Lv,Mingjiang Hu,Tianhao Yuan,Liqiang Yan,Hongwei Chen
The objective of this work was to investigate and contrast the mechanism of different B-site dopants for catalytic activity and sulfur resistance under equivalent conditions. LaCo1−xMxO3 (M = Fe, Cr, Cu) perovskite-type catalysts were synthesized by a sol–gel method, and the optimized samples were tested for toluene oxidation before and after sulfur aging. The properties of the catalysts were investigated in detail by XRD, FT-IR, N2 adsorption–desorption, H2-TPR, XPS and in situ DRIFTS to elucidate the inner mechanisms of the catalytic reaction and poisoning processes. The results indicated that introducing specific metal cations with a suitable ratio into the B-site of perovskite could improve the catalytic activity and weaken the negative effect of SO2 poisoning. The reasons for the improvement of catalytic activity on different doped catalysts are similar and mainly lie in the change of reduction property, oxidation state of the B-site, and content of oxygen vacancies. However, the mechanism of sulfur resistance caused by different dopants is not identical. The introduction of different metal cations will cause certain differences in some factors such as reducibility, lattice stability, sulfur adsorption and sulfate content, thus leading to the differentiation of sulfur tolerance for doped perovskite catalysts. In this study, the optimization effect of Fe dopant is better than that of Cr and Cu dopants, illustrating that the high stability of the perovskite lattice and the insensitivity to sulfur species are the key factors for its outstanding sulfur resistance. The results provide insights into guiding the practical composition and life cycle optimization of perovskite-type catalysts in the industrial application of removing sulfur-containing VOCs.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 63
·33347-33354
·
IF 3.708
Tieyong Xu,Qunfeng Zhang,Dahao Jiang,Qiuxia Liang,Chunshan Lu,Jie Cen,Xiaonian Li
Sulfur deactivation is a serious problem which largely limits the industrial application of noble metals as catalysts. Here we report a thermal oxidation method to regenerate sulfone poisoned Pd/C catalyst applied in the hydrogenation of sodium-m-nitrobenzene sulfonate (SNS). It was found that the initial activity of Pd/C catalyst could be substantially recovered after treating it in air at temperatures as low as 100 °C. And the catalyst could be reused for at least 20 times without the significant loss of activity. The properties of deactivated and regenerated catalysts were studied in detail by BET measurement, X-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and Fourier transform infrared spectroscopy (FT-IR). The results indicated that the main surface sulfur species found on deactivated and regenerated Pd surfaces were Sn and sulfate (SO4), respectively. The change of the valence of sulfur species was found to be the key factor influencing the catalytic activity of the Pd-based catalyst.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Yu Chen,Lei Jiang,Bing Bao,Chunqiang Lu,Yunkun Zhao,Shiying Chang,Dongxia Yang,Depeng Zhao,Xianming Cheng,Hua Wang,Kongzhai Li
With the improvement of current global vehicle emission standards increase and widespread application of natural gas vehicles (CNG), existing three-way catalytic converters (TWCs) need to be modified to meet the new emission regulations. In recent years, the price of palladium has been rising, while platinum, which is also used in catalytic systems, is relatively cheap, and the industry has come up with the idea of replacing palladium with platinum. Palladium loaded with a mass fraction of 1% on Ce 0.4 Zr 0.5 La 0.05 Y 0.05 O 1.95 (CZLY) did show excellent catalytic activity, however, when palladium is replaced by platinum, the catalytic activity of the catalyst for methane combustion is significantly reduced. At 680 °C under oxygen-rich conditions (20%), methane conversion can typically reach 90%. The reduced 1% Pt/CZLY catalyst, on the other hand, was unstable in activity at high temperatures, although it was significantly higher at the starting temperature (T 50 = 378 °C). In this work, it was found that the addition of niobium to CZLY improved the activity of Pt-based catalysts. The 1% Pt/Ce 0.4 Zr 0.5 La 0.05 Nb 0.05 O 2 (1% Pt/CZLN) catalysts showed a decrease in T 90 (CO) of 26 °C and T 90 (CH 4 ) of approximately 250 °C. The activity of this catalyst is consistent with that of the reduction pre-treatment 1% Pt/CZLY catalyst. Results from thermal deactivation and sulphur poisoning experiments show that the 1% Pt/CZLN catalyst exhibits superior thermal stability and anti-sulphur toxicity. For example, methane conversion of the 1% Pt/CZLN catalyst maintained at 85% at 600 °C for 32 h with a 5% decrease in activity. To clearly explain the effect of niobium doping on the catalyst, BET, XRD, H 2 -TPR, XPS and TEM tests were performed on the catalysts confirming that the strong Pt-Nb interaction stabilizes the valence state of the platinum and loads the platinum on the carrier surface in the active metallic platinum state. The amount of niobium doping was positively correlated with the metallic Pt content in the catalyst. In conclusion, the addition of niobium to platinum-based catalysts increases the methane combustion activity of the catalyst and delays thermal deactivation and sulphur poisoning of the platinum-based catalyst, extending the service life of the platinum-based catalyst.
研究领域:
催化材料
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2024
·
IF 3.3
Fumei Wang,Qi Cai,Xinhua He,Boxiong Shen,Leila Negahdar,Shuo Feng,Andrew M. Beale
Cu/SAPO-34 catalysts have been widely used for the reduction of NOx from diesel exhaust by ammonia-selective catalytic reduction (SCR). Sulfur poisoning remains a challenge for Cu/SAPO-34 catalysts in NH3–SCR, restricting its application. In this study, Cu/SAPO-34 samples containing a mixture of Cu species comprising isolated Cu2+ located in the 6MR, Cu(OH)+ in 8MR, CuO clusters/nanoparticles, and Cu+ species were prepared. The Cu speciation during SO2 and hydrothermal aging of Cu/SAPO-34 SCR catalysts was subsequently studied. While hydrothermal aging had little effect on catalytic activity, the sulfur-aged sample exhibited deterioration in NH3–SCR activity over the temperature range of 100–575 °C. The breakage and collapse of the zeotype framework and chemical deactivation of the Cu/SAPO-34 catalyst after exposure to SO2 and H2O took place. A combination of X-ray photoelectron spectroscopy (XPS) and TGA-DT-DSC revealed the presence of ammonium bisulfate, copper bisulfate/sulfate, aluminum sulfate, and sulfuric acid after SO2 and H2O copoisoning under SCR conditions. Furthermore, Cu(OH)+ tended to migrate to form isolated Cu2+ and Cu+, as well as agglomerate to form CuO particles. Density functional theory (DFT) calculations revealed that SO2 and O2 could readily be absorbed by CuO particles to form stable copper bisulfate/sulfate species with the following order of preference: CuO > Cu+ > Cu2+ > Cu(OH)+. In contrast, Cu(OH)+ was less prone to be poisoned by easily releasing SO3 than other Cu species sites.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Bin Hu,Kaijie Liu,Xin Shen,Xiaohui Chen,Feng He,Yangfei Fang,Mingcai Liu,Haijiao Xie,Yibo Zhang,Xiangguang Yang
Up to now, methane combustion catalysts generally suffer from issues such as poor reaction stability and susceptibility to sulfur poisoning, which have become the key factors restricting their application, so it is necessary to construct catalysts with excellent chemical stability of the active center and strong sulfur resistance. Here, we showed the crystal phase-modulated state of PtO x nanoparticles (PtO x NPs) on TiO 2 and investigated their effects on the reactivity of methane catalytic combustion and anti-SO 2 poisoning properties. It was found that Pt/r-TiO 2 showed superior activity, stability, and resistance to SO 2 poisoning. Transmission electron microscope (TEM) images showed that the PtO x NPs on the surface of r-TiO 2 were much more stable than a-TiO 2 for the reason that the Ostwald ripening of PtO x NPs on a-TiO 2 was facilitated due to the strong metal-support interaction (MSI) between PtO x NPs and TiO 2 and the low migration energy of the PtO x NPs on TiO 2 , while they were moderate of Pt/r-TiO 2 , and then the active sites were stabilized during methane combustion. The activity was controlled by the size and electronic structure of PtO x NPs, which were stable on the surface of r-TiO 2 with a higher Pt 4+ content, and the density functional theory (DFT) calculations further revealed the role of r-TiO 2 in increasing the quantities of surface oxygen vacancies . Moreover, the SO 2 tolerance of Pt/r-TiO 2 was also the best among all kinds of Pt-based catalysts prepared, which was attributed to the minimal adsorption energy ( E ad ) of SO 2 on r-TiO 2 , and the absence of sulfate and sulfite deposition on the Pt/r-TiO 2 catalyst confirmed by TGA and in-situ DRIFTS studies on SO 2 adsorption. In this research, the anti-SO 2 poisoning and reaction stability were realized by adjusting the interaction between SO 2 , active components, and supports, which provided a new insight for the design of stable Pt-based SO 2 -resistant catalysts.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Jianwen Lai,Hongbo Qi,Yunfeng Ma,Xiaoqing Lin,Xiaoying Wang,Zhongkang Han,Heidelore Fiedler,Xiaodong Li
Cerium is widely used as a modifier to enhance the catalytic performance of the selective catalytic reduction (SCR) catalysts due to its exceptional low-temperature properties. However, the effects of different cerium precursors on catalytic performance remains unclear. In this study, VO x -WO x /TiO 2 catalysts are modified using Ce(NO 3 ) 3 ·6H 2 O (cata-N), CeO 2 (cata-O), and Ce(OH) 4 (cata-OH), and their synergistic removal of NO x and chlorobenzene (CB), as well as their resistance to water and sulfur poisoning, were systematically investigated. Among the tested catalysts, cata-N demonstrated superior CB (45.0–93.3 %) and NO x (31.9–90.37 %) removal efficiencies under synergistic conditions, along with excellent water resistance (T 90 = 193 °C with 5 % H 2 O). In contrast, cata-OH exhibited the highest sulfur resistance, maintaining a denitrification efficiency of 20 % after 10 h of sulfur exposure, compared to 9 % for cata-N and 8 % for cata-O. Characterization revealed that Ce(NO 3 ) 3 ·6H 2 O improved cerium dispersion, leading to enhanced the redox properties and acidity (especially Brønsted acid sites (BAS)) in cata-N. Density functional theory (DFT) calculations and In-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy ( In-situ DRIFTS) results revealed that the well-dispersed cerium atoms contributed additional BAS in the form of Ce–OH, while also forming Ti–O–Ce bonds. These Ti–O–Ce bonds facilitated the formation of Ti–OH on the TiO 2 surface. Ti–OH significantly enhanced the adsorption of NH 3 and CB, thereby promoting both the NH 3 -SCR and CB oxidation processes. This study offers new insights into the role of cerium precursors and provides a practical strategy for tuning BAS of catalysts in multiple pollutants removal.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED ENERGY
·
2020
·
IF 8.848
Yu Chen,Minyi Lu,Huazheng Yang,Yingbang Yao,Tao Tao,Shengguo Lu,Chao Wang,Rajendran Ramesh,Michaela Kendall,Kevin Kendall,Xiaoping Ouyang,Bo Liang
High power density and simple design are vital for these fuel cell-based portable power generation devices. This study provides an 8.6 g tubular SOFC with embedded a catalytic partial oxidation reformer, which is fabricated and operated for more than 100 h using propane/air. Nickel-iron nanosheets, as catalysts for reforming, supported on α-Al 2 O 3 foam ceramic are synthesized by hydrothermal treatment. Testing for 80 h gives a power degradation of about 20% compared with the initial value. It is mainly attributed to sulfur-poisoning of nickel near anode/electrolyte interface according to transmission electron microscope (TEM) analysis. From TEM/energy dispersive spectroscopy line-scan results across the anode/electrolyte interface, sulfur as either aggregate at the nickel/yttria-stabilized zirconia grain boundaries or on the nickel grain surface, and no obvious carbon phase is founded. The maximum power density is 0.67 W cm −2 at 700 °C using propane/air (12 vol% propane), about 5% higher than the same cell using 20 vol% hydrogen.
研究领域:
能源科学
·
材料科学
✓ 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）