FUEL PROCESSING TECHNOLOGY
·
2016
·
IF 3.847
Wei Li,Rui-tang Guo,Shu-xian Wang,Wei-guo Pan,Qi-lin Chen,Ming-yuan Li,Peng Sun,Shu-ming Liu
Heavy metals (such as Zn and Pb) have a deactivation effect on the catalyst for selective catalytic reduction of NO with NH 3 . In this study, it was found that the modification of Mn/TiO 2 catalyst by Nb could greatly enhance its Zn resistance. From the characterization results of BET, XRD, H 2 -TPR, NH 3 -TPD, it may be concluded that the introduction of Nb into Mn/TiO 2 catalyst would lead to its lower crystallinity , more acid sites and higher concentrations of Mn 4 + and surface chemisorbed oxygen. The results of in situ DRIFT study reveal that the NH 3 -SCR reactions over Mn/TiO 2 and Mn-Nb/TiO 2 all obey both the Langmuir-Hinshelwood mechanism and the Eley–Rideal mechanism, and the doping of Nb on Mn/TiO 2 catalyst could promote the adsorption of NH 3 and NOx species on it. All these features make a contribution to the high SCR activity and good Zn resistance of Mn-Nb/TiO 2 catalyst.
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
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 43
·20777-20785
·
IF 3.925
Yanke Yu,Mengqiao Geng,Desheng Wei,Chi He
Selective catalytic oxidation of NH3 (NH3-SCO) is a promising method to reduce NH3 pollution. The Pt-based catalysts exhibited excellent activity in the NH3-SCO reaction under low temperatures. However, it was easy for the NH3 to be oxidized to N2O and NOx (NO and NO2) over the Pt-based catalyst, causing a low N2 selectivity. The CuSO4, which could supply both Brønsted and Lewis acid sites on the catalyst, was used to promote N2 selectivity. The N2 adsorption–desorption, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma mass spectrometry (ICP-MS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were used to characterize the catalyst. The addition of CuSO4 could suppress the formation of N2O and NOx, thus the highest N2 selectivity on the catalyst increased from 21.2% to 78.1%. An imide mechanism was the main reaction mechanism on the Pt/TiO2 catalyst. After adding CuSO4, the NH3-SCO reaction over the CuSO4-Pt/TiO2 catalyst mainly followed an i-SCR mechanism where NH3 was oxidized to N2O and NOx, and then the newly formed N2O and NOx were reacted with NH3/NH4+ adsorbed on the Lewis and Brønsted acid sites via an NH3-SCR reaction over the catalyst, and finally N2 was formed. The acid sites performed an important role in the formation of N2 and this work should provide an effective method to promote N2 selectivity in a NH3-SCO reaction.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS RESEARCH
·
2018
·Vol. 33
·期 16
·2414-2422
·
IF 1.495
Youchun Pan,Yuesong Shen,Qijie Jin,Shemin Zhu
A series of Ba-modified MnCeOx/TiO2 catalysts were prepared by a wet impregnation method and tested for selective catalytic reduction (SCR) of NO with NH3 at low temperature. The results showed that Ba additives obviously improved the catalytic performance of the MnCeOx/TiO2 catalyst for NH3-SCR, and the BaMnCeOx/TiO2 catalyst with 3 wt% BaO exhibited the optimal catalytic performance. Moreover, the introduction of Ba also improved the resistances toward water vapor and SO2 of catalysts. The N2 adsorption, H2-TPR, and X-ray photoelectron spectroscopy results showed that the addition of Ba increased the specific surface area, redox properties, and concentrations of surface Mn4+ and chemisorbed oxygen of catalysts. Furthermore, NH3-TPD and NO-TPD were used to investigate the absorption of NH3 and NO on the catalyst. The results revealed that although the introduction of Ba significantly promoted the adsorption of NO, it also inhibited the adsorption of NH3. Consequently, the catalytic performance of MnCeOx/TiO2 was greatly improved with the Ba additives.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
FUEL
·
2017
·
IF 4.601
Shaojian Jiang,Xi Liu,Hailong Li,Jun Wang,Zequn Yang,Haoyi Peng,Kaimin Shih
Elemental mercury (Hg 0 ) oxidation over a low-temperature La 2 O 3 -TiO 2 (LaTi) catalyst through a fixed-bed reactor system is reported here. Despite the presence of oxygen (O 2 ), Hg 0 was not effectively oxidized by either hydrogen chloride (HCl) or nitrogen oxide (NO). However, Hg 0 oxidation over the LaTi catalyst was greatly improved when both HCl and NO were present in the simulated flue gas. Several methods, including X-ray photoelectron spectroscopy (XPS), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and temperature-programmed decomposition (TPD), were used to study the inherent mechanisms involved in the Hg 0 oxidation by HCl and NO. The results indicated that the combined presence of HCl and NO exhibited great synergy for Hg 0 catalytic oxidation over the LaTi catalyst. The reaction mechanism is proposed as follows: 1) NO was adsorbed and oxidized on the catalyst surface, forming NO 2 ; 2) the reactive NO 2 then oxidized gas phase Hg 0 to mostly HgO, and; 3) HgO reacted with gas phase HCl to produce HgCl 2 , which escaped from the catalyst’s surface. Differing from previously proposed mechanisms, La 2 O 3 was first studied as an active substance in Hg 0 oxidation. These findings are beneficial for those seeking economical and efficient Hg 0 oxidation catalysts for coal-fired power plants.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2021
·
IF 3.995
Li Huang,Yiqing Zeng,Yibo Gao,Hu Wang,Yuhao Zong,Zhengfeng Chang,Shule Zhang,Pei Han,Yang Yu
The oxidation of SO 2 into SO 3 promote the formation of NH 4 HSO 4 (ABS), which can cover surface active sites catalyst, and then leading to the decrease of NH 3 -SCR De-NO x activity. In this work, phosphorus species were loaded on the V 2 O 5 -MoO 3 /TiO 2 De-NO x catalyst to enhance its SO 2 resistance via inhibiting the SO 2 /SO 3 conversion. XRD and N 2 -adsorption results showed that phosphorus has little impact on the structure and pore property of the catalyst. The results of XPS , H 2 -TPR, and NH 3 -TPD analyses illustrated that suitable amount of phosphorus (1%) increases the content of polymeric vanadate and chemisorbed oxygen (O α ) of the catalyst, which is benefit to the SCR process. Phosphorus species decreases the SO 2 absorbability and SO 2 oxidation activity of V-Mo-P/Ti catalysts, thus it exhibits higher NH 3 -SCR activity than that of the P-free catalyst at presence of SO 2 due to the lower SO 2 /SO 3 conversion and fewer amount of NH 4 HSO 4 deposition.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 149
·期 7
·2004-2014
·
IF 2.372
Wang Jian,Zhao Hainan,Liu Xiaolong,Xu Wenqing,Guo Yangyang,Song Jianfei,Zhu Tingyu
In this work, we presented a detailed evaluation of Ru/TiO 2 (P25) catalysts for the catalytic oxidation of (chloro)-aromatics. The model catalysts were synthesized through wet impregnation. Catalytic evaluations, as well as ICP, BET, XRD and TEM analyses, were conducted. The results indicated that RuO 2 tended to be distributed on the rutile phase of TiO 2 , leading to an inhomogeneous distribution. These Ru/TiO 2 catalysts were very active, especially for chlorobenzene oxidation. The conversions of benzene and chlorobenzene were both suppressed by the introduction of additional water. But the amount of polychlorinated benzenes as by-products was also reduced. However, the activity of the catalyst significantly decreased with an increase in calcination temperature, suggesting that the thermal stability of the catalyst still needed to be improved. Graphical Abstract
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 22
·27663-27673
·
IF 3.056
Liu Yuan-zhen,Xu Qi-yan,Guo Rui-tang,Duan Chao-peng,Wu Gui-lin,Miao Yu-fang,Gu Jing-wen
The Cu/TiO 2 catalysts with the addition of Eu were developed by the sol-gel way for the selective catalytic reduction (SCR) of NO x by NH 3 . Activity tests revealed that CuEu/TiO 2 -0.15 catalyst showed the optimal de-NO x performance in a wide temperature range (150–300 °C), along with an admirable SO 2 tolerance. According to characterization analysis, the relationship between the NH 3 -SCR performance and physicochemical characters of samples was explored. The adjunction of Eu on Cu/TiO 2 catalyst can contribute to the formation of a large amount of Cu 2+ , adsorbed oxygen, and acid sites on the catalyst surface. Moreover, the Eu addition on Cu/TiO 2 is favorable to the generation of activated NO x and NH 3 substances adsorbed on the catalyst surface, which would conduce to the NH 3 -SCR process by Langmuir-Hinshelwood (L-H) mechanism effectively.
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
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2020
·Vol. 27
·期 24
·30243-30253
·
IF 3.056
Xu Wenqing,Gao Lei,Yang Yang,Zhu Tingyu,Qi Guisheng
The deposition of NH 4 HSO 4 on catalysts is one of the key issues for selective catalytic reduction of NO x . In this study, NH 4 HSO 4 was preloaded on catalysts, and the effects of MoO 3 and CeO 2 doping on the decomposition and reactivity of NH 4 HSO 4 on V 2 O 5 /TiO 2 catalysts are studied. The results show that the introduction of MoO 3 and CeO 2 significantly promoted NO x conversion on the V 2 O 5 /TiO 2 catalysts. Doping with MoO 3 could effectively enhance the S and H 2 O resistance of the catalysts. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicate that it is the strong chemical interactions between NH 4 HSO 4 and the catalysts that are adverse to the decomposition of NH 4 HSO 4 . However, doping with MoO 3 apparently inhibits these interactions, which significantly decrease the decomposition temperature of NH 4 HSO 4 . In situ FTIR experiments show that the NH 4 + in preloaded NH 4 HSO 4 could react with gaseous NO on catalysts, and doping with MoO 3 could facilitate the reaction rate.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Hailun Zhao,Chao Wang,Weilin Zhong,Suqing Peng,Riyang Shu,Zhipeng Tian,Ying Chen
Probing the effect of spatial morphology of catalyst on its photothermal catalytic performance is crucial for solar-driven renewable catalytic reforming of hydrogen production . In this study, Au nanoparticles loaded on various morphologies of TiO 2 nanoparticles were synthesized and characterized. The experimental results indicated that decorating TiO 2 with Au nanoparticles could dramatically increase its photocatalytic activities by 20–40 times. The photothermal conversion efficiency of Au/TiO 2 (12.74%–25.54%) was higher than those of TiO 2 due to the introduction of LSPR of Au nanoparticles could effectively improve the utilization of solar spectrum. Titania nanoflower (TNF) nanoparticles with high light absorption capacity , better colloidal dispersion stability , porous properties and narrow band gap represented the highest H 2 productivity (144.13 μmol·g −1 ·h −1 ). The coarse surface structure was also conducive to the dispersion of gold particles on the surface of the carrier and the growth rate of Au/TNF hydrogen production (40 times) which was higher than that of other morphology within 2 h. The results of glycerol photothermal hydrogen generation highlighted the effect of temperature on colloidal dispersion stability and hydrogen production capability of nanoparticle suspension. It demonstrated that the photothermal effect aroused a temperature rise that would deteriorate the dispersion stability of the suspension although a local entropy increase in the catalyst nanoparticles might occur. At the same time, the temperature rise caused by the photothermal effect efficiently produces hydrogen in the reaction temperature range. Therefore, an ideal temperature setting for maximal hydrogen generation could be validated and improved the photothermal synergistic impact on biomass-reformed hydrogen generation.
研究领域:
化学工程
·
材料科学
·
可再生能源
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2019
·
IF 4.309
Zhencan Hu,Haiying Qin,Xuezhang Xiao,Man Chen,Meijia Liu,Ruicheng Jiang,Lixin Chen
NaMgH3 has been considered to be a potential candidate for solid-state hydrogen storage due to its considerable hydrogen gravimetric (6.0 wt %) and volumetric (88.0 g/L) densities. Meanwhile, NaMgH3 possesses an outstanding theoretical thermal storage density of 2881 kJ/kg, which makes it one of the most promising thermal energy storage materials. However, the sluggish dehydrogenation kinetics of NaMgH3 embarrasses further practical application. Doping a nanosize Ti-based catalyst is treated to be one of the most effective methods to settle the poor dehydriding kinetics. In this work, different kinds of TiO2 catalysts, the 5 wt % TiO2 microparticle (MP) (100 nm), TiO2 nanoparticle (NP) (5–10 nm), and TiO2 nanotube (NT) (5–10 nm), were doped into NaMgH3 in the process of ball milling and heat treatment, which in situ formed Na0.46TiO2 significantly promoting the full hydrogen desorption kinetics of NaMgH3. Among all samples, the TiO2 NT-doped sample shows the best performance of which the onset decomposition temperature is reduced to 300 °C, and the first- and second-step decomposition peak temperatures are decreased to 346.3 and 355.8 °C, respectively. The TiO2 NT-doped sample desorbs approximately 3.4 wt % H2 at 350 °C within 10 min, while the pure NaMgH3 sample releases only 0.2 wt % H2 in 10 min. The significant improvement in both two decomposition reactions kinetics of NaMgH3 can be attributed to the tubular morphology of the TiO2 NT and the in situ formation of multivalence Ti species (Na0.46TiO2). These two reasons can change the kinetic models of NaMgH3 from A2 to R2 and further dramatically decrease the activation energies of first- and second-step decomposition reactions of NaMgH3 to 91.7 and 142.1 kJ/mol, respectively. In particular, the in situ formed Na0.46TiO2 can benefit the e– transfers among Na+, Mg2+, and H–, tremendously enhancing dehydrogenation properties.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Yiqing Zeng,Fengye Lyu,Yanan Wang,Shule Zhang,Qin Zhong,Zhaoxiang Zhong
High N 2 O selectivity of MnO x -TiO 2 catalyst hinders its development in ammonia selective catalytic reduction (NH 3 -SCR) of NO x . Herein, a series of MnO x -TiO 2 catalyst with different Mn/Ti ratio were prepared by wet-impregnation method to study the N 2 O formation during ammonia selective catalytic reduction (NH 3 -SCR) of NO x from the perspective of catalyst. It is found that MnO x and TiO 2 species are the mainly redox and acid sites for the NH 3 -SCR denitration reaction over MnO x -TiO 2 catalyst, respectively. As the Mn/Ti ratio increases, MnO x species layer expanded on TiO 2 support, leading to increase of redox sites but decrease of surface acid sites. These changes contribute to the occurrence of the no-selective oxidation of NH 3 on MnO x species and the over-activation of NH 3 at Mn-Ti interface, resulting in the formation of N 2 O via the route of 2NH 3 + 2O 2 → N 2 O + 3H 2 O and 4NO + 4NH 3 + 3O 2 → 4N 2 O + 6H 2 O, respectively. Through this work, it can be speculated that both improving MnO x dispersion and increasing surface acidity of catalyst are feasible strategy for suppressing the N 2 O formation on MnO x -TiO 2 .
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
·
2021
·Vol. 11
·期 15
·5125-5134
·
IF 6.119
Yanke Yu,Xianfang Yi,Jiali Zhang,Zhaojian Tong,Changwei Chen,Mudi Ma,Chi He,Jinxiu Wang,Jinsheng Chen,Bingbing Chen
Non-vanadium-based catalysts with high SO2 tolerance are still interesting in selective catalytic reduction of NO by NH3 (NH3-SCR) and SO2 adsorption is the foremost step for the deactivation of catalysts. In order to alleviate the adsorption of SO2, we fabricated a series of rhenium (Re; without stable sulfate) supported TiO2 catalysts and studied their SO2 tolerance for the first time. Owing to suitable surface acidity and reducibility, ReOx/TiO2 catalysts exhibited satisfactory activity in a wide temperature range of 250–350 °C. As expected, experimental results and DFT calculations indicated that SO2 adsorption on ReOx/TiO2 catalysts was rather weak, thus the catalysts performed excellent SO2 tolerance in the NH3-SCR reaction. Moreover, in situ DRIFTS indicated that the NH3-SCR reaction on ReOx/TiO2 catalysts followed the Eley–Rideal mechanism and SO2 had little effect on the reaction mechanism. Our findings should provide new insights into the development of SCR catalysts with high SO2 tolerance.
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
危险品化学品经营许可证（带存储）