Frontiers of Environmental Science & Engineering
·
2022
·Vol. 17
·期 3
·1-12
·
IF 6.048
Gao Yuchen,Jiang Jianguo,Meng Yuan,Ju Tongyao,Han Siyu
Biogas is a renewable biomass energy source mainly composed of CH 4 and CO 2 . Dry reforming is a promising technology for the high-value utilization of biogas. Some impurity gases in biogas can not be completely removed after pretreatment, which may affect the performance of dry reforming. In this study, the influence of typical impurities H 2 S and NH 3 on dry reforming was studied using Ni/MgO catalyst. The results showed that low concentration of H 2 S in biogas could cause serious deactivation of catalyst. Characterization results including EDS, XPS and TOF-SIMS confirmed the adsorption of sulfur on the catalyst surface, which was the cause of catalyst poisoning. We used air calcination method to regenerate the sulfur-poisoned catalysts and found that the regeneration temperature higher than 500 °C could help catalyst recover the original activity. NH 3 in the concentration range of 50–10000 ppm showed a slight inhibitory effect on biogas dry reforming. The decline rate of biogas conversion efficiency increased with the increase of NH 3 concentration. This was related to the reduction of oxygen activity on catalyst surface caused by NH 3 . The synergetic effect of H 2 S and NH 3 in biogas was investigated. The results showed that biogas conversion decreased faster under the coexistence of H 2 S and NH 3 than under the effect of H 2 S alone, so as the surface oxygen activity of catalyst. Air calcination regeneration could also recover the activity of the deactivated catalyst under the synergetic effect of H 2 S and NH 3 .
研究领域:
能源化学
·
催化化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2016
·
IF 2.628
Yanke Yu,Jinsheng Chen,Jinxiu Wang,Yanting Chen
A series of CuSO 4 /TiO 2 catalysts were prepared using a wet impregnation method. The activity of each sample in the selective catalytic reduction of NO by NH 3 (NH 3 -SCR) was determined. The effects of SO 2 and H 2 O, and their combined effect, on the activity were examined at 340 °C for 24 h. The catalysts were characterized using N 2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction of H 2 (H 2 -TPR), temperature-programmed desorption of NH 3 (NH 3 -TPD), and in situ diffuse-reflectance infrared Fourier-transform spectroscopy (DRIFTS). The CuSO 4 /TiO 2 catalysts had good activities, with low production of N 2 O above 340 °C. SO 2 or a combination of SO 2 and H 2 O had little effect on the activity, and H 2 O caused only a slight decrease in activity during the experimental period. The NH 3 -TPD and H 2 -TPR results showed that CuSO 4 increased the amounts of acid sites and adsorbed oxygen on the catalyst. In situ DRIFTS showed that the NH 3 -SCR reaction on the CuSO 4 /TiO 2 catalysts followed an Eley–Rideal mechanism. The reaction of gaseous NO with NH 3 adsorbed on Lewis acid sites to form N 2 and H 2 O could be the main reaction pathway, and oxygen adsorption might favor this process.
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
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
JACS Au
·
2025
·
IF 8.7
Xuan Bie,Yukun Pan,Xiaowei Wang,Shiyu Zhang,Jiahui Hu,Xiaoxiao Yang,Qinghai Li,Yanguo Zhang,Robert E. Przekop,Yayun Zhang,Hui Zhou
Gas sources rich in CO2 derived from biomass/waste gasification, anaerobic digestion, or industrial carbon capture often contain impurities such as H2S, H2O, and NH3, which can significantly hinder catalyst performance. Here, we show the role of NH3 on the reverse water–gas shift (RWGS) reaction over a commercial Cu/ZnO/Al2O3 catalyst, examining its effects on both the catalytic activity and the catalyst structure. We found that NH3 reversibly decreases CO2 conversion immediately by suppressing carbonate hydrogenation and CO desorption. This effect intensifies with an increase in NH3 concentration but decreases at higher temperatures. However, prolonged exposure (over 100 h) to RWGS conditions in the presence of 1.4% NH3 leads to near-total and irreversible deactivation of the Cu/ZnO/Al2O3 catalyst. Under NH3 exposure, the catalyst loses Cu+ sites on the surface, causing a spatial separation of Cu and ZnO. Finally, to address this challenge, we propose a novel strategy to mitigate NH3 inhibition by decomposing NH3 into N2 and H2.
研究领域:
化学工程
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催化科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2025
·
IF 5.4
Jian Gao,Xinrui Dai,Zhenhua Gu,Guixian Deng,Jiangyong Yuan,Kongzhai Li
Catalysts loaded with metal oxides of M (M = Mn, Co, Ce) were synthesized by deposition precipitation method using cold rolled sludge (iron oxide as the main component) as a raw material for the selective catalytic reduction of NO x by ammonia (NH 3 -SCR). Among the various formulations, the co-supported catalyst containing 5 % Mn and 5 % Co on CRS-400 exhibited exceptional SCR performance, achieving over 90 % conversion of NO x from 80 °C to 200 °C. The addition of 5 % Mn and 5 % Co as active components resulted in an increase in the specific surface area for catalytic performance and an enhancement of the redox capacity, leading to a significant improvement in catalyst activity. The catalyst’s efficient denitration performance was attributed to the synergistic interaction between Mn, Co, and Fe oxides, resulting in a catalyst with a higher proportion of adsorbed oxygen, as well as an elevated composition of Mn 4+ and Fe 2+ species. The catalyst demonstrated excellent SCR activity at low-temperatures, indicating its potential for downstream applications in soot treatment equipment. This would achieve the dual benefits of purifying the atmosphere and disposing of solid waste.
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
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 6
·1300-1312
·
IF 7.779
Nangui Lv,Chenhu Sun,Xueqin Wang,Chan Wang,Yuanyuan Yue,Xiaojun Bao
Synthesizing CHA-type zeolite via template-free interzeolite transformation has been considered as a green method, but the resultant zeolite exhibits low activity in the selective catalytic reduction of NOx by ammonia (NH3-SCR). Herein we report a highly active NH3-SCR catalyst (Cu-CHAUSY) derived from CHA-type zeolite (CHAUSY) that is synthesized via template-free interzeolite transformation from ultra-stable Y (USY). The ultra-high activity is attributed to the specific silicon and aluminum configurations in USY which are distinctly different from those in the conventionally used parent NaY, although they have similar SiO2/Al2O3 ratios. This characteristic endows CHAUSY with more single Al atoms in a six-membered ring, benefiting the self-reduction of [Cu(OH)]+ and the activation of O2 during the NH3-SCR reaction. Moreover, Cu-CHAUSY is demonstrated to outperform the two reference catalysts prepared from the aluminosilicate gel by conventional hydrothermal crystallization with the assistance of organic templates. Our work provides a new strategy for preparing highly active NH3-SCR catalysts.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Yaping Yang,Xuesong Liu,Zhiming Sui,Yanghui Wang,Ping Fang,Peng Jiang,Xiaodong Wu
The purpose of this study is to investigate the interaction of Ce and W species with TiO 2 , Al 2 O 3 and SiO 2 supports, so as to illustrate the influence of supports and distribution of Ce, W species on SCR reaction. It is found that low-temperature activity followed the order of CeW > CeWTi > CeWAl > CeWSi. The reasons for the various activity of the catalyst were investigated by a series of characterization. The low-temperature NH 3 -SCR activity is associated with the surface concentrations of Ce 3+ , oxygen vacancies and active oxygen species, which are dominated by the dispersion and interactions of Ce/W species with the supports. Arising from interactions of Ti 4+ with high-density electron cloud, finely dispersed Ce and W species facilitate the W-Ce synergism and produce more active oxygen. All these contribute toTiO 2 can make Ce and W species in an ideal distribution, so the corresponding catalyst shows excellent NO x conversion of CeWTi catalyst at 200–350 °C. The reaction process observed by in situ DRIFT indicated that the NH 3 -SCR reaction on CeO 2 -WO 3 containing catalysts mainly follow Langmuir-Hinshelwood (L-H) mechanism at low temperature. Based on the analysis of the characterization and reaction process, it is concluded that the control step of NH 3 -SCR reaction at low temperature over CeO 2 -WO 3 containing catalysts is the adsorption and activation of NO x .
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
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Bingbing Yang,Lu Bai,Shaojuan Zeng,Shuangjiang Luo,Lei Liu,Jiuli Han,Yi Nie,Xiangping Zhang,Suojiang Zhang
As ecological pollution and resource waste caused by NH 3 emission become increasingly serious, thus the separation and recovery of NH 3 from exhausted gases is of great significance both for environment and economy. Herein, we present a kind of novel ionic liquids (ILs)-based hybrid membranes for efficient NH 3 separation. Protic ILs (PILs) are adopted to form self-assembled gas highways in the hybrid membranes with the nanostructures of a middle-sulfonated pentablock copolymer, exhibiting extremely high NH 3 affinity and gas diffusion. The highest NH 3 permeability and ideal NH 3 /N 2 selectivity is up to 2711 Barrer and 1407 at ambient temperature and 1 bar, much superior to the state-of-the-art membranes reported. The results indicated that the novel IL-based hybrid membranes are promising candidates for high-efficient NH 3 separation and purification.
研究领域:
环境科学
·
材料科学
✓ 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
Crystals
·
2023
·Vol. 13
·期 7
·1005
·
IF 2.7
Zhiwei Liu,Guanlong Li,Yan Zhao,Xiangbao Chen
The rapid development of electronic technology has brought convenience and efficiency to the lives of modern people, while emphasizing the need for novel materials with designability and excellent dielectric properties at the same time. In this work, Ti3C2TxMXene nanosheets (MNSs) underwent NH3·H2O solvothermal treatment at temperatures of 40 °C, 60 °C, 80 °C, 100 °C, 120 °C, 140 °C, 160 °C, and 180 °C. The changes in the surface groups and dielectric properties after the solvothermal treatment were studied. The solvothermal treatment increased the proportion of surface -OH groups, which was beneficial to the permittivity of the MNSs. However, as the treating temperature increased, the amount of -OH on the surface of the MNSs showed a reducing trend, according to XPS spectra. As the treating temperature rose from 40 °C to 80 °C, the real part of the permittivity of MNS sample showed a significant decrease, eventually remaining approximately stable in the 80 °C to 180 °C samples. The results of electromagnetic characterization were in line with the group proportion, as determined via the XPS O1s spectra, supporting the previous conclusion that the -OH group played an important role in the permittivity.Keywords:NH3·H2O solvothermal;end groups;dielectric property;2D nanosheets
研究领域:
材料科学
·
纳米技术
·
电子学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Peipei Zhao,Mingyu Guo,Qingling Liu,Lijun Fan,Jinfeng Han,Caixia Liu,Na Ji,Chunfeng Song,Degang Ma,Zhenguo Li
A series of Mn a Zr b Cr c O x catalysts with different Cr/Mn molar ratios were synthesized via co-precipitation for the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). It was found that a Mn 5 Zr 2 Cr 2.5 O x catalyst with a Mn:Zr:Cr ratio of 5:2:2.5 exhibited excellent low-temperature activity and the best levels of H 2 O resistance at a high weight hourly space velocity (WHSV) of 54,000 ml/(h·g). NO conversion levels were measured as greater than 87% within a temperature range of 150–250 °C, and catalytic performance levels reached 90% even 50 h after reactions occurred in the presence of 15% H 2 O at 230 °C. The characterization results show that strong interactions occurring between Mn, Zr and Cr oxides and higher quantities of Mn 4+ and Lewis acid sites improved the redox properties and facilitated H 2 O resistance. In situ diffuse reflectance infrared Fourier transform spectra ( in situ DRIFTS) show that coordinated NH 3 on Lewis acid sites and bidentate nitrates play important roles in SCR reactions and that such reactions follow both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanisms. The competitive adsorption of H 2 O and NO may be the main cause of the adverse effects of H 2 O on catalytic performance.
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
WATER AIR AND SOIL POLLUTION
·
2021
·Vol. 233
·期 1
·1-17
·
IF 2.52
Zhang Shujuan,Yun Wenfei,Xia Yu,Wu Sikai,You Zhaoyang,Matthias C. Rillig
This study aims to investigate the role of arbuscular mycorrhizal (AM) symbiosis in reducing N loss from paddy fields, using two rice lines: a mycorrhiza-defective rice line (non-mycorrhizal) and its mycorrhizal progenitor. Two rice lines were grown in the presence of an AM fungal isolate. In this study, N loss of runoff, leaching, N 2 O emission, and NH 3 volatilization were measured, and in addition, N uptake of rice, soil aggregates, and plant available N concentration of soil. The results obtained suggest that N loss via runoff, leaching, NH 3 volatilization, and N 2 O emission of mycorrhizal rice was 11%, 8%, 6%, and 1%, lower than that of non-mycorrhizal rice, respectively. Meanwhile, mycorrhizal rice has higher biomass and plant N uptake. Our study shows that the AM symbiosis contributes to the sustainability of rice production by reducing N loss, enhancing soil aggregation and increasing plant N uptake.
研究领域:
植物学
·
环境科学
·
农业科学
✓ 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）