Journal of Natural Gas Chemistry
·
2012
·
IF 1.348
Lincai Peng,Junping Zhuang,Lu Lin
Effects of Zr/Ti molar ratio in SO 2− 4 /ZrO 2 -TiO 2 solid acid catalyst calcined at different temperatures on its surface properties and catalytic activity were thoroughly investigated in this paper. The physicochemical characteristics of prepared samples were determined by N2 adsorptiondesorption, XRD, NH3-TPD and XPS techniques, respectively. It was found that the crystallization temperature of the samples increased after the combination of ZrO 2 and TiO 2 ; and phase transformations from the anatase to the rutile of TiO 2 species and the tetragonal to the monoclinic of ZrO 2 species were effectively suppressed at higher temperature. The sample with a Zr/Ti molar ratio of 3/1 calcined at 450 °C showed the highest surface area and the most acid sites among all the tested samples. The acid site densities of samples were relatively closed to each other if they were calcined at the same temperature, however, decreased with the calcination temperature. The result indicates that the sulfur content in samples is a crucial factor to control the acid site density. Calcining the sample at 650 °C and higher temperatures resulted in a significant desorption of sulfate ion on the samples. The synthesized samples were evaluated as a potential catalyst for glucose conversion under the near-critical methanol conditions (200 °C/4 MPa). The results suggested that the relatively weaker acid sites of the catalyst were more favorable for the accumulation of methyl glucosides, while the moderate acid sites were responsible for the formation of methyl levulinate. The catalytic activity for methyl levulinate production almost increases linearly with the catalyst acid site density. The catalyst deactivation is due to the loss of sulfate ion and the two catalysts with Zr/Ti molar ratios of 3/1 and 1/3 could effectively alleviate the deactivation caused by sulfate solution in the reaction medium and can be reused after calcination with the reuse rate of over 90% in terms of the methyl levulinate selectivity.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Weiyuan Yao,Yue Liu,Zhongbiao Wu
A series of CeO 2 @Ce-O-P “multi-core@shell” catalysts were synthesized in this paper for selective catalytic reduction (SCR) of NO with NH 3 . The experimental results had showed that CeO 2 @Ce-O-P-30:3 yielded best SO 2 tolerance of an over 70% deNO x efficiency at 250 °C in the presence of 100 ppm SO 2 for 20 h, which was much higher compared to pure Ce-O-P and CeO 2 samples. Further characterization results indicated that Ce-O-P coating layer could somewhat inhibit sulfur depositing on the catalysts during SCR reaction in the presence of SO 2 , thereby protecting the active sites from SO 2 poisoning. Especially, O 2 -TPD results illustrated that a great amount of active oxygen species were retained on used CeO 2 @Ce-O-P catalyst after a long term reaction. The synergetic effect of “multi-core@shell” structure could be attributed to such enhanced performances. The “core” CeO 2 devoted abundant active oxygen sites to fulfill the SCR reaction. And the “shell” Ce-O-P could not only provide acid sites, but also protect the active oxygen species by avoiding the over-adsorption of SO 2 on the catalyst. This work could provide a new way to increase the sulfur resistance for low temperature SCR catalysts.
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Huirong Zhang,Lin Luo,Zixiong Zhao,Yi Shen,Jinglei Cui,Xiaokai Shi,Xiaoliang Han
The production of high-performance activated carbon (AC) is recognized as an essential strategy for the effective utilization of lignin resources. In this work, the N-doped AC was successfully prepared by blending sodium lignosulfonate (SL) and different ratios of FeCl 3 through one-pot strategy. The AC structure evolution and performance were obtained by a series of characterization and tests. The results showed that, during the activation process, FeCl 3 first complexed with urea and catalyzed the depolymerization of SL, and the rapid pore development was mainly caused by the template, including formed FeCl 2 , Na 2 Fe 3 Cl 8 and Na 6 FeCl 8 . The ratio of FeCl 3 /SL adjusts the AC physicochemical texture. AC-3 processed a super total specific surface area and pore volume, respectively up to 2048 m 2 /g and 1.47 cm 3 /g. Meanwhile, AC-2 showed a higher nitrogen content of 11.4 %. The as-prepared AC shows super desulfurization, denitrification and Cr (Ⅵ) removal ability. AC-2 displayed maximum sulfur capacity and NO conversion, up to 199.1 mg/g and 42.4 %. This enhanced performance is primarily attributed to the pore structure induced by FeCl 3 activation, which provides a foundation for adsorption and catalytic processes, further augmented by the increased active sites due to nitrogen doping. AC-3 achieved an extremely high Cr (VI) adsorption capacity, up to 386.2 mg/g, which was primarily attributed to the redox effect of N-containing and O-containing groups on Cr (VI), in addition, the effect of physical adsorption including pore structure is not neglectable. This study highlights the significant potential of environmentally friendly lignin-based porous carbon materials for removing contaminants in both gas and liquid phases.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
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2021
·
IF 5.706
Huansheng Tan,Shibo Ma,Xiaoyu Zhao,Yushi Li,Chen Zhao,Yujun Zhu
Bimetallic W a CeO x (a = 0.06, 0.12, 0.18, 0.24) catalysts were synthesized for selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). The influences of W on structure, activity and surface properties were investigated by XRF, XRD, Raman, TEM, N 2 adsorption-desorption, H 2 -TPR, O 2 /NH 3 /SO 2 -TPD, XPS, and in-situ DRIFTS. The characterization results show that the W/Ce ratio has a great effect on the NH 3 -SCR activity. The different catalytic activities of W a CeO x are mainly attributed to the acidity change, especially the increase of B-acid content plays a major role in enhancing low temperature activity. W 0.18 CeO x exhibits excellent low-temperature NH 3 -SCR activity, SO 2 /H 2 O resistance and N 2 selectivity with a broad activity window (190–490 °C) with 5%H 2 O. Moreover, good activity window (235–460 °C) can be maintained even the catalyst treated with 5% H 2 O at 800 °C for 12 h, showing especial hydrothermal stability. Thus, it can be summarized that W 0.18 CeO x is regarded as outstanding catalyst for low-temperature NH 3 -SCR of NO.
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DOI
高影响因子
RSC Advances
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2016
·Vol. 6
·期 86
·82707-82715
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IF 3.289
Wei Li,Rui-tang Guo,Shu-xian Wang,Wei-guo Pan,Qi-lin Chen,Ming-yuan Li,Peng Sun,Shu-ming Liu
A series of Mn/CeSiOx catalysts were prepared by the wet impregnation method and used for selective catalytic reduction of NO with NH3. As can be seen from the experimental results, the Mn/CeSiOx catalyst with a Ce/Si molar ratio of 2/1 showed excellent low-temperature SCR activity, high N2 selectivity and excellent SO2 and H2O tolerance. The relationship between the CeSiOx support and the SCR performance of Mn/CeSiOx (2 : 1) catalyst was investigated based on the characterization results of N2 adsorption, XRD, XPS, H2-TPR, NH3-TPD and in situ DRIFT. The strong interaction between Ce and Si resulted in the good dispersion of Mn species on the support; correspondingly, the redox ability and NH3 adsorption capacity were greatly enhanced. The results of in situ DRIFT study revealed that the NH3-SCR reactions over Mn/CeO2 and Mn/CeSiOx (2 : 1) mainly obeyed both the E–R mechanism and the L–H mechanism. Furthermore, the formation of more Mn4+ and chemisorbed oxygen greatly facilitates the oxidation of NO to NO2, as a result, promoting the low-temperature SCR performance of Mn/CeSiOx (2 : 1).
研究领域:
催化
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环境科学
·
化工
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DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Xinrui Li,Gaoshan Xing,Qian Yang,Jianfeng Zhou,Guorui Yao,Liqiang Qi
Currently, the desulfurization agents employed in dry desulfurization technology face challenges such as slow reaction rates and low desulfurization efficiency. This study integrates phosphotungstic acid(HPW) into Cu-based Metal-organic framework(Cu-MOFs) using a hydrothermal synthesis method, enhancing the performance of the desulfurization agent through a combination of catalytic oxidation and adsorption. Experimental results indicate that optimal desulfurization effects are achieved when the ratio of Copper nitrate trihydrate (Cu(NO 3 ) 2 ) to 1, 3-phenyltrifamilic acid (H 3 BTC) is 2:1, with an HPW addition of 1.2 wt%, and a hydrothermal synthesis duration of 24 hours. In a fixed bed desulfurization system, HPW-2@Cu-MOF demonstrates the best performance at a reaction temperature of 200℃, achieving a sulfur dioxide removal efficiency nearing 100 %, a specific surface area of 612.20 m 2 /g, a pore volume of 0.2568 cm 3 /g, and a sulfur capacity of 90.464 mg/g. The incorporation of HPW facilitates the conversion of sulfur dioxide (SO 2 ) to sulfur trioxide (SO 3 ) under the influence of surface oxygen (O α , O β ), resulting in a 10.52 % increase in SO 3 content compared with Cu-MOFs. When the flue gas contains a certain concentration of carbon dioxide, HPW-2@Cu-MOF preferentially reacts with SO 2 due to the adsorption between Cu 2+ and SO 2 . X-ray photoelectron spectroscopy (XPS) characterization reveal that W 5+ serves as the active center in HPW, the content of W 5+ in HPW-2@Cu-MOF was higher than others, accounting for 90.6 %. Thermo Gravimetric Analysis clearly demonstrates that the thermal stability of Cu-MOFs loaded with HPW has been significantly enhanced.
研究领域:
化学工程
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环境科学
✓ 已验证
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Zhong-yi Wang,Rui-tang Guo,Xu Shi,Wei-guo Pan,Jian Liu,Xiao Sun,Shuai-wei Liu,Xing-yu Liu,Hao Qin
The Cu/TiO 2 catalysts modified by Sb were compounded through the sol-gel way and put into use for the selective catalytic reduction (SCR) of NOx with NH 3 . Experimental results suggested that CuSb/TiO 2 -0.4 exhibited the excellent NOx conversion and SO 2 tolerance. Subsequently, the relationship between surface physicochemical properties and catalytic performance was also investigated by different characterization methods. From characterizations, the introduction of Sb for Cu/TiO 2 could promote the generation of more Cu 2+ , surface adsorbed oxygen species and surface acid sites on CuSb/TiO 2 -0.4 catalyst. Furthermore, Sb species on CuSb/TiO 2 -0.4 could contribute to the formation of more surface ad-NOx and ad-NH 3 species, which would enhance the NH 3 -SCR process effectively through both the Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms.
研究领域:
催化
·
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）