INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2017
·
IF 3.582
Yinghui Sun,Guojie Zhang,Jiwei Liu,Peiyu Zhao,Peng Hou,Ying Xu,Riguang Zhang
CH 4 CO 2 reforming to syngas was investigated over three different activated carbon catalysts. To better understand the influence of the supports on the catalytic properties , catalysts were analyzed by some characterization methods, such as nitrogen adsorption–desorption isotherms, XRD , H 2 -TPR, NH 3 -TPD, CO 2 -TPD, FTIR, TEM and EDX . The results showed that the catalyst with AC 2 as the support provided the best catalytic activity . The CH 4 conversion and CO 2 conversion were 92% and 98% at 900 °C, respectively; best selectivity with the H 2 /CO ratio was close to 1 among the three supports used. It also showed a better stability at 900 °C. H 2 -TPR analysis showed that Co species in Co/AC 2 catalyst were strong interaction with the support. It was observed that active metals were well dispersed on the AC 2 support by the TEM. In addition, the ratio of CH 4 /CO 2 also had great influence on the CH 4 and CO 2 conversion.
研究领域:
催化
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化学工程
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材料科学
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产品关联
DOI
高影响因子
Reaction Chemistry & Engineering
·
2022
·Vol. 8
·期 1
·64-76
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IF 5.2
Haosheng Xin,Haiyong Wang,Xiaohong Hu,Xiuzheng Zhuang,Long Yan,Chenguang Wang,Longlong Ma,Qiying Liu
Cellulose hydrolysis and further conversion to diketones and alcohols was performed with graphene layer encapsulated cobalt catalysts (Co@C) in phosphoric acid aqueous solution. A total of 60.5% yield of the products mainly including ethanol, 2,5-hexanedione (2,5-HD) and diols could be achieved in 0.06 M H3PO4 solution. A series of characterization methods such as XRD, XPS, TEM, TG-MS, BET, ICP, H2-TPD, NH3-TPD, and Raman were carried out to explore the catalyst formation mechanism and reaction activity. The results of the analysis indicated that the calcination temperature had a deep influence on the structure formation of the Co@C catalysts, thus leading to differences in the reaction activity. While the calcination temperature was determined at 700 °C, the Co@C catalyst meets with the requirements of optimal reaction activity, appropriate particle size, suitable surface area, and pore size. Besides, it was found that H3PO4 is not only favorable in cellulose hydrolysis but also cooperates with the Co@C catalyst in the hydrogenolysis of C–O bond and C–C bonds for the formation of products. This work provides a possible way for renewable cellulose conversion to diketone and alcohols over encapsulated non-noble metal catalyst combined with phosphoric acid aqueous solution.
研究领域:
化学工程
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催化
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可再生能源
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
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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
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催化化学
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DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
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2017
·Vol. 19
·期 7
·5333-5342
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IF 4.123
Shu-xian Wang,Rui-tang Guo,Wei-guo Pan,Ming-yuan Li,Peng Sun,Shu-ming Liu,Shuai-wei Liu,Xiao Sun,Jian Liu
It was well recognized that Pb had a poisoning effect on a SCR catalyst. In this study, the deactivation mechanism of Pb on the Ce/TiO2 catalyst was investigated based on the characterization results of TPD and in situ DRIFT studies. It was found that the addition of Pb on the Ce/TiO2 catalyst not only inhibited the adsorption and activation of NH3 species, but also led to the decrease of the activity of adsorbed NH3 species in the SCR reaction. The adsorption of NOx species and the oxidation of NO by O2 over the Ce/TiO2 catalyst were also suppressed by the addition of Pb, while the reactivity of adsorbed NO2 species did not decrease. Moreover, the results revealed that the NH3-SCR reaction over the Ce/TiO2 catalyst followed both the E–R and L–H mechanisms, while the NH3-SCR reaction over Ce/TiO2-Pb was mainly controlled by the L–H mechanism. The contributions of the L–H mechanism to the SCR reactions over Ce/TiO2 and Ce/TiO2-Pb decreased with increasing reaction temperature. The deactivation of Ce/TiO2-Pb was mainly attributed to the suppressed NH3 adsorption and activation, accompanied by the inhibited NO oxidation and the decrease of Brønsted acid sites.
研究领域:
环境催化
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大气污染控制
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材料化学
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表面科学
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物理化学
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
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2022
·
IF 11.072
Yuhai Sun,Jingyi Han,Kai Xu,Keying Wu,Wei Wu,Xu Zhang,Boqiong Jiang
Aromatic ring-opening process is considered as the rate-determining step for catalytic toluene decomposition. However, the ring-opening pathway has not been fully revealed, especially the effect of the surface species in plasma catalytic hybrid system. Herein, a series of Mn based catalysts (with the low Mn content of 1 wt %), Mn/γ-Al 2 O 3 , Au-Mn/γ-Al 2 O 3 and Ag-Mn/γ-Al 2 O 3 , were used to clarify the mechanism of plasma catalytic toluene degradation by a closely combined temperature-programmed desorption (TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Effects of plasma on surface oxygen species were investigated by a comparison study of O 2 -TPD and plasma-excited O 2 -TPD. A strong interaction between plasma and Ag-Mn/γ-Al 2 O 3 could make better use of plasma-induced active oxygen species ( i.e. O 3 , O*, O 2 * etc. ) and considerably increase the amount of chemically adsorbed oxygen. Moreover, modified NH 3 -TPD experiments proved that O 2 excited by plasma would greatly change the surface acidity of Ag-Mn/γ-Al 2 O 3 , resulting in the desorption activation energy (E d ) of toluene increasing to 19.5 kJ/mol. Finally, possible ring-opening mechanisms over different catalysts were proposed after the evolution of typical intermediates being systematically analyzed by in situ DRIFTS. It was found that the toluene ring-opening reaction on different catalysts might be selectively started at hydroquinone. The present work could provide both a more detailed toluene ring-opening process and new insights into the understanding of the plasma exciting effect on the surface species in VOCs decomposition.
研究领域:
催化
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等离子体化学
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环境科学
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表面科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
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2017
·Vol. 7
·期 51
·32146-32154
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IF 3.108
Chengkai Pang,Yuqun Zhuo,Qiyu Weng
A series of Mn-exchanged SAPO-34 catalysts were synthesized and developed as catalysts for the low temperature selective catalytic reduction (SCR) of NO with ammonia in the presence of excess oxygen. 4Mn/SAPO-34 showed the highest SCR activity in the temperature range of 120–210 °C. The microstructure of zeolite supports, acidity, manganese species and reaction mechanism were investigated in detail by BET, NH3-TPD, UV-Vis, H2-TPR, XPS and in situ DRIFTS. Mn3+ and Mn4+ related species were proved to be the active sites for the SCR reaction. The Eley–Rideal mechanism was proved to be effective on 4Mn/SAPO-34 for the low temperature SCR reaction in which coordinated NH4+ species react with gas-phase NO to form an activated transition state and subsequently decomposed to N2 and H2O.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
DYES AND PIGMENTS
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2023
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IF 4.5
Peiyu Wu,Shengxiong Zhang,Wenjun Zhang,Weijie Song
Dual functional electrochromic (EC)/electrofluorochromic (EFC) materials play a pivotal role in wearable and smart electronic equipments. Developing new materials with high performance of EC/EFC properties is still a big challenge. Here a new D-A structure polymer PPDOTTPD based on thieno(3,4-c)pyrrole-(4,6)dione ( TPD ) was synthesized by Stille coupling, and the EC/EFC properties were investigated for the first time. PPDOTTPD film exhibits reversible color changes from purple neutral state to transparent colored state in the process of reversible redox. Photophysical and electrochemical studies revealed that the polymer has outstanding EC properties, including high optical contrast (52%), fast response time (0.5 s/0.7 s), high coloring efficiency (427.1 cm 2 C −1 ) and good stability. What's more, PPDOTTPD exhibited EFC phenomenon. PPDOTTPD film showed an intense red near-infrared fluorescence with a peak of 672 nm, which gradually doped with the increase of applied potential with a maximum contrast ratio of 12.9. The EC/EFC dual-functional device based on PPDOTTPD was also successfully fabricated, which exhibited high optical and fluorescence contrast. The fine dual-functional performance indicates TPD can be further explored as potential acceptors for synthesizing high performance D-A molecules for intelligent optical devices.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
Solar RRL
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2022
·Vol. 6
·期 12
·2200862
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IF 9.173
Kai Wang,Bo Yu,Changqing Lin,Ruohe Yao,Zuorong Nie,Hong Wang,Huangzhong Yu
The rapid development of perovskite solar cells (PSCs) perovskite is inseparable from the investigation of plentiful new additive materials. Herein, a conjugated organic material called TPD-Br containing two carbonyl groups and Br atoms is synthesized. TPD-Br with Lewis-base groups can provide excellent passivation for defects between perovskite layer and electron transport layer. Furthermore, Br atom can also interact with iodine ions via halogen bonds. TPD-Br passivates the perovskite defects because it can interact with undercoordinated Pb 2+ ions by forming Pb O bond, lower defect density and larger grain size occur in the perovskite can be obtained. Consequently, high-quality perovskite films with fewer defects can be fabricated. The PSCs with TPD-Br additive achieve a champion power conversion efficiency of 20.74%. These results illustrate that TPD-Br, as a superior passivate defect additive, can improve the performance and stability of PSCs.
研究领域:
材料科学
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能源技术
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Zhengfeng Gu,Daiwei Liu,Mengnan Yu,Teng Bao,Xiaowei Liu,Ling Zhang,Haitao Ding,Zhimin Yu,Chengxun Deng
The synthesis of supported transition metal oxides with satisfactory low-temperature catalytic performance and application potential is still a challenge for the complete degradation of VOCs. Ni-Cu-loaded TiO 2 catalysts were prepared by an impregnation method. The lattice defect and oxygen vacancy concentrations of the prepared materials could be tuned by controlling the Ni/Cu molar ratio and the mass proportion of the TiO 2 support. 5Ni-Cu/TiO 2 exhibited the best catalytic activity and showed superior catalytic stability during complete toluene oxidation . The obtained catalysts were fully characterized by XRD, FT-IR, TEM, N 2 adsorption analysis, XPS, H 2 -TPR, O 2 -TPD, TPD analysis, and XPS. The 5Ni-Cu/TiO 2 catalyst had improved pore sizes and specific surface area, had more oxygen vacancies on its surface, had increased concentrations of adsorbed and lattice oxygen species, and had good redox properties; these characteristics were favorable for low-temperature catalytic performance and catalytic stability. Cyclic transformations of metal valence states between Cu + and Cu and between Ni and Ni 2+ were observed in the catalytic system. A potential catalytic reaction process based on the M-vK mechanism was proposed. This work serves as a reference for the application of supported transition metal catalysts for the degradation of VOCs.
研究领域:
催化
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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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2018
·
IF 4.521
Ting Yi,Yibo Zhang,Xiangguang Yang
Pt@CeO 2 /MCM-56 (PCM) and CeO 2 -CuO (9:1)/MCM-56 (CCM) were combined to purify the exhaust emissions from diesel vehicles in three configuration statuses, defined as configuration A—where CCM stays above PCM, configuration B—where PCM stays above CCM, and configuration C—where CCM mixes with PCM homogeneously in loose contact. Among these combined catalysts, the configuration A is most favorable for the selective catalytic reduction (SCR) reaction, with >80% NO x conversion obtained at the temperature range of 150–550 °C and gas hourly space velocity (GHSV) of 240,000 ml g −1 h −1 . NH 3 -TPD, H 2- TPR and NH 3 conversion measurements demonstrated that NH 3 can be selectively used to reduce NO x in the configuration A but is over-oxidized if the reaction is operated in configuration B or configuration C status, deteriorating the deNO x activity at temperature above 250 °C. Hence, configuration A not only takes advantage but also overcomes the shortcomings of PCM and CCM, leading to high NO x conversion and N 2 selectivity. A significant decrease in the onset temperature of soot combustion was also observed in this research.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 10
·2255
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IF 4.2
Yan Cui,Zequan Zeng,Yaqin Hou,Shuang Ma,Wenzhong Shen,Zhanggen Huang
Noble metals have become a research hotspot for the oxidation of light alkanes due to their low ignition temperature and easy activation of C-H; however, sintering and a high price limit their industrial applications. The preparation of effective and low-noble-metal catalysts still presents profound challenges. Herein, we describe how a Ru@CoMn2O4spinel catalyst was synthesized via Ru in situ doping to promote the activity of propane oxidation. Ru@CoMn2O4exhibited much higher catalytic activity than CoMn2O4, achieving 90% propane conversion at 217 °C. H2-TPR, O2-TPD, and XPS were used to evaluate the catalyst adsorption/lattice oxygen activity and the adsorption and catalytic oxidation capacity of propane. It could be concluded that Ru promoted synergistic interactions between cobalt and manganese, leading to electron transfer from the highly electronegative Ru to Co2+and Mn3+. Compared with CoMn2O4, 0.1% Ru@CoMn2O4, with a higher quantity of lattice oxygen and oxygen mobility, possessed a stronger capability of reducibility, which was the main reason for the significant increase in the activity of Ru@CoMn2O4. In addition, intermediates of the reaction between adsorbed propane and lattice oxygen on the catalyst were monitored by in situ DRIFTS. This work highlights a new strategy for the design of a low-noble-metal catalyst for the efficient oxidation of propane.
研究领域:
催化
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CLAY SCIENCE
·
2019
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IF 3.89
Haiyan Yang,Yang Zhou,Dongshen Tong,Miao Yang,Kai Fang,Chunhui Zhou,Weihua Yu
Cellulose is the most abundant form of biomass on earth, and is considered as an alternative for fuels and chemicals. The hydrolysis of cellulose to platform compounds, such as reducing sugars (RS), is one of the most important ways for the utilization of cellulose. In this study, the solid acid catalysts of SO 4 2− -ZrO 2 /montmorillonite (SZ-Mt) were prepared by coupling SO 4 2− with ZrO 2 and then introducing into the interlayer of Mt using the coprecipitation method. Meanwhile, the catalytic performance of the SZ-Mt catalysts for the hydrolysis of cellulose to RS in water was studied. The catalysts were characterized by XRD , FT-IR, BET, SEM(EDS), NH 3 -TPD and XPS . The catalytic results showed that the SZ-Mt composite calcined at 500 °C with the molar ratio of S/Zr of 0.3 showed the highest total reducing sugars yield of 30.1%. The characterization results revealed that the surface S O bonds of sulfated zirconium oxide could gradually change from O=S-OH groups (type I, -HSO 4 ) to O=S=O groups (type II, -S 2 O 7 ). It was concluded that the surface S-OH groups in type I were responsible for the hydrolysis of cellulose in the low molar ratio of S/Zr and the new S-OH bonds formed by breaking the S-O-S bonds in type II were contributed to the conversion of cellulose in the high molar ratio of S/Zr. Finally, the mechanism of cellulose hydrolysis on the SZ composites was suggested.
研究领域:
化学工程
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材料科学
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生物化学
✓ 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）