ENERGY & FUELS
·
2020
·
IF 3.421
Jie Yu,Esong Zhang,Lele Wang,Zijian Song,Fanhai Kong,Yunlong Ma,Hong Zhao,Lushi Sun
With the wide application of selective catalytic reduction (SCR) systems in power plants for the control of NOx emission in China, a serious problem of catalyst deactivation due to the channel blockage by NH4HSO4 has drawn extensive attention. In this work, a combined experimental and simulation method was utilized to study the interaction between NH4HSO4 and a vanadium–titanium-based catalyst. Initially, the adsorption characteristics of NH4HSO4 onto TiO2, V2O5/TiO2, V2O5-WO3/TiO2, and V2O5-MoO3/TiO2 were simulated following density functional theory. The simulation revealed that during reaction, the NH4HSO4 loaded onto TiO2 can be dissociated into NH4+ and SO42–. The existence of V2O5, WO3, and MoO3 can form a protective layer to inhibit the adsorption of NH4HSO4 onto TiO2, to promote the reduction of sulfur-containing compounds, and to accelerate the reaction of NH4+ with NO. Thermogravimetric analysis also showed the positive effect of V, W, and Mo on NH4HSO4 decomposition. Fixed-bed experiments were then conducted to compare the performance of the studied catalysts and the effect of NH4HSO4 on their performance. It was proven that the V-5Mo/TiO2 catalyst showed better performance at low temperatures. On the V-5Mo/TiO2 catalyst, ∼78 wt % NH4+ in NH4HSO4 was attached onto Lewis acid sites, which can accelerate the reduction reaction of NO by NH4+. Meanwhile, SO42– can comparatively be easily decomposed at lower temperatures.
研究领域:
环境科学
·
催化化学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zhengkang Peng,Xun Gong,Zijian Zhou,Shiwei Dong,Wei Hu,Hanxiao Liu,Jingying Xu
The removal of naphthalene is important but deficient, so that the available V-W/Ti catalysts (1.0 wt% V 2 O 5 /TiO 2 ) were prepared for its efficient abatement in this work. Especially, influences of different existence status of vanadium species on naphthalene elimination were investigated via changing the pH value of precursor solution. With the increase of precursor solution acidity, more highly polymeric vanadium species were formed on the catalyst surface. The redox capability was enhanced markedly as a consequence of the stronger electron transfer between V/W and Ti that induced more surface active oxygen and V 5+ , whereas the catalytic activity was obviously boosted and almost 90 % conversion of naphthalene was achieved at 293 °C. Moreover, the weaker chemisorption between naphthalene and V-W/Ti catalyst allowed the deeper conversion to CO x . GC–MS manifested that naphthalene seemed to be an organic component that was difficult to be totally degraded. Naphthalene oxidation was in the following pathway of naphthalene → 1,4-naphthoquinone → phthalic anhydride → phthalates → benzene → benzoquinone → maleic anhydride → CO x /H 2 O. The opening of aromatic ring in phthalic anhydride and benzene ring in benzene were proven to be the rate-controlling step based on in-situ DRIFTS results. The key of naphthalene oxidation was the complete degradation of various intermediates.
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
Journal of Energy Storage
·
2023
·
IF 9.4
Hui Yong,Yiwan Chen,Yanquan Ji,Shuai Wang,Jiangwei Ma,Baosheng Liu,Jifan Hu,Yanghuan Zhang
Solid-state magnesium-based hydrogen storage encounters challenges associated with sluggish hydrogen absorption and desorption kinetics. The incorporation of catalysts is considered a promising means to improve the hydrogen absorption and desorption kinetics of these alloys. In this experiment, we prepared the Mg 80 Ni 15 Y 5 alloy via vacuum melting and incorporated TiF 3 in varying weight percentages of 1, 3, 5, and 7 wt% through ball milling . The phase composition and microstructure of the samples were analyzed and measured using X-ray diffraction meter (XRD), Transmission Electron Microscope (TEM), Selected Area Electron Diffraction (SAED), and Scanning Electron Microscope (SEM) techniques. The results revealed that the TiF 3 introduced two catalytically phases, MgF and TiF 2 . And TiF 2 transforms into TiH 2 after hydrogen absorption, which covers the surface of MgH 2 and prolongs the nucleation time of MgH 2 .Furthermore, the addition of TiF 3 made the surface of alloy markedly coarser and more irregular and few cracks, providing channels for hydrogen diffusion. This behavior optimized the kinetic performance of the alloy. It was observed that the samples containing 7 wt%TiF 3 achieved 99.2 % hydrogen saturation even in low-temperature. It's worth mentioning that the addition of 7 wt% TiF 3 to the Mg 80 Ni 15 Y 5 alloy significantly reduced the dehydrogenation activation energy to 58.5 kJ/mol, as opposed to pure magnesium with an activation energy of 158.2 kJ/mol. This substantial reduction has effectively accelerated the hydrogen absorption and desorption rates of the alloy. However, it had only a negligible impact on the thermodynamic properties of the sample with 7 wt%TiF 3 .
研究领域:
材料科学
·
能源储存
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Yujie Lv,Bao Zhang,Haixiang Huang,Xuebin Yu,Tingting Xu,Jinting Chen,Bogu Liu,Jianguang Yuan,Guanglin Xia,Ying Wu
The 0.55LiBH 4 -0.45Mg(BH 4 ) 2 (LMBH) eutectic composite is promising for solid-state hydrogen storage, as it exhibits a high hydrogen capacity and a very low initial dehydrogenation temperature. However, its main hydrogen release steps still require higher temperatures. In the present study, few-layer Ti 2 C has been synthesized and utilized as catalysts in the LMBH. Compositing LMBH with varying amounts of Ti 2 C (10, 20, 30, and 40 wt%) results in low initial dehydrogenation temperatures (164–110 °C), fast desorption rates and high hydrogen capacities (7.5–10.5 wt%) at a low temperature of 260 °C. The LMBH-30Ti 2 C composite yields 6.5 wt% H 2 even at as low as 200 °C. Additionally, the LMBH-30Ti 2 C composite could reversibly store 3.5 wt% H 2 during the second to fourth dehydrogenation cycles without degradation. The outstanding hydrogen storage performance could be attributed to decomposition driven by reactions between high-valence Ti ions and LMBH, the in-situ formation of the active metal Ti catalyst, and the prevention of aggregation in the Ti 2 C-doped LMBH.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Tianyu Lan,Na Zhang,Liduo Chen,Cuiqin Li,Jun Wang
The 1.0G dendrimer polyamidoamine (PAMAM), 3,5-dichlorosalicylaldehyde, and TiCl4·2THF were used as synthetic materials, and the dendritic salicylaldehyde imide ligand with substituent hindrance and its titanium catalyst were synthesized by the condensation reaction of Schiff base. The structure of the synthesized products was characterized by infrared spectroscopy, nuclear magnetic resonance hydrogen spectroscopy, ultraviolet spectroscopy, electrospray mass spectrometry, and inductively coupled plasma-mass spectrometry. Activated methylaluminoxane (MAO) was used as a catalyst precursor for ethylene polymerization in the process of ethylene catalytic. The effects of ethylene polymerization were studied in terms of the Al/Ti molar ratio, reaction time, reaction temperature, polymerization pressure, and ligand structure of the catalyst. The results show good catalytic performance (70.48 kg PE/mol Ti·h) for ethylene polymerization because of the existence of ortho substituent hindrance on the salicylaldehyde skeleton. Furthermore, high-temperature gel permeation chromatography (GPC)-IR, differential scanning calorimetry (DSC), and torque rheometer were used to characterize the microstructure, thermal properties, and viscoelastic state of the polyethylene samples obtained. The results showed that the product was ultrahigh-molecular-weight polyethylene.
研究领域:
化学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Weikun Chen,Xiao Fu,Xiaoying Liu,Linmin Ye,Youzhu Yuan
N -alkylated piperazines can be synthesized by the thermal catalytic alkylation of piperazine with alkyl halides or alcohols in the presence of supported metal catalysts. However, these processes either discharge large amounts of waste or require harsh conditions. Here, we report the results of N -alkylation of piperazine with lower alcohols (methanol, ethanol, and propanol) without external hydrogen addition at room temperature in the presence of a TiO 2 -supported Pd catalyst (Pd/TiO 2 -P) prepared by photodeposition method. Compared with the catalysts prepared by the conventional chemical reduction or hydrogen reduction, the Pd/TiO 2 -P catalyst showed the highest conversion of piperazine and the best selectivity to N -alkypiperazines. The mechanistic studies indicated that this phenomenon occurs via tandem photocatalytic reactions involving alcohol dehydrgenation to aldehyde, aldehyde condensation with piperazine to enamine, and enamine hydrogenation to N -alkylated piperazines. Considering the experimental results of methanol isotope kinetics, the α-C–H cleavage of methanol to form hydroxymethyl radical (·CH 2 OH) was proven to be the rate-determining step in the N -alkylation reaction of piperazine with low carbon alcohols. The characterization and control experiments revealed that the size of Pd nanoparticles and the valence of Pd species were vital to the reaction. The Pd/TiO 2 -P catalyst with an average of 2.5 ± 0.5 nm Pd particles and approximately 68% Pd 0 species on surfaces presented the highest activity for the photocatalytic tandem reactions of methanol dehydrogenation and enamine hydrogenation.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Xuesong Liu,Peng Jiang,Yong Chen,Yaoguang Wang,Qiaoling Ding,Zhiming Sui,Hongfeng Chen,Zhongyun Shen,Xiaodong Wu
Two Ce-W-Ti mixed oxide catalysts were prepared by wet impregnation (CeW/Ti-I) and mechanical mixing (Ce/W/Ti-M) methods. CeW/Ti-I catalyst exhibits over 80% NO x conversion and nearly 100% N 2 selectivity at 200–550 °C. The superior catalytic performance is associated with the high dispersion of active CeO 2 and acidic WO 3 on TiO 2 and the synergistic effects among different components. The X-ray Diffraction, Raman spectroscopy, Nitrogen physisorption, X-ray photoelectron spectroscopy, H 2 temperature-programmed reduction, temperature-programmed desorption of ammonia and infrared spectroscopy were performed. It is found that the formation of solid solutions, as well as the high specific surface area, would increase the amounts of Ce 3+ , oxygen vacancies and acid sites in the catalyst. These broaden the operating temperature window of NH 3 -SCR reaction and enhance the N 2 selectivity by facilitating “fast SCR” reaction at low temperatures and inhibiting the unselective oxidation of NH 3 at high temperatures.
研究领域:
催化化学
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环境科学
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产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
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2017
·Vol. 35
·期 7
·866-873
·
IF 1.692
Liang Hua-qing,Zhou Qi-hua,Long Yong-jiang,Wei Wan-chu,Liang Guo-dong,Wu Qing,Gao Hai-yang,Zhu Fang-ming
Herein, we demonstrate the synthesis of a well-defined diblock copolymer consisting of isotactic polystyrene ( i PS) and linear polyethylene, isotactic polystyrene-block-polyethylene ( i PS- b -PE), by the combination of sequential monomer addition and hydrogenation. Isospecific living polymerization of styrene and living trans -1,4-polymerization of 1,3-butadiene were catalyzed by 1,4-dithiabutandiyl-2,2′-bis(6-cumenyl-4-methylphenoxy) titanium dichloride (complex 1) activated by triisobutyl aluminum modified methylaluminoxane (MMAO) at room temperature to provide highly isotactic polystyrene ( i PS) and 1,4- trans -polybutadiene (1,4- trans -PBD) with narrow molecular weight distribution. Furthermore, the iPS-b-1,4- trans -PBD was synthesized via sequential monomer addition in the presence of complex 1 and MMAO. The hydrogenation of the 1,4- trans -PBD block was promoted by RuCl 2 (PPh 3 ) 3 used as a catalyst to produce i PS- b -PE.
研究领域:
高分子化学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Fan Yang,Lulu Zhang,Feifei Li,Zhipeng Zhang,Luyao Cui,Rui Li,Caimei Fan,Jianxin Liu
Hydrogen spillover effects will significantly improve the activity of photocatalytic hydrogen evolution reactions (HER), while their introduction and optimization require the construction of an excellent metal/support structure. In this study, we have synthesized Ru/TiO 2-x catalysts with controlled oxygen vacancy (OVs) concentrations using a simple one-pot solvothermal method . The results show that Ru/TiO 2-x3 with the optimal OVs concentration exhibits an unprecedentedly high H 2 evolution rate of 13604 μmol·g −1 ·h −1 , which was 45.7 and 2.2 times higher than that of TiO 2-x (298 μmol·g −1 ·h −1 ) and Ru/TiO 2 (6081 μmol·g −1 ·h −1 ). Controlled experiments, detailed characterizations, and theoretical calculations have revealed that the introduction of OVs on the carrier contributes to the hydrogen spillover effect in the metal/support system photocatalyst and that the process of hydrogen spillover in this system can be optimized by modulating the OVs concentration. This study proposes a strategy to decrease the energy barrier of hydrogen spillover and enhance photocatalytic HER activity. Moreover, it investigates the effect of OVs concentration on the hydrogen spillover effect in the photocatalytic metal/supports system.
研究领域:
材料科学
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催化化学
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Changshun Deng,Xiaorong Zhu,Jun Yao,Yibo Wang,Chenyang Shen,Bingqing Ge,Chaoxiang Li,Nianhua Xue,Luming Peng,Xuefeng Guo,Yan Zhu,Yafei Li,Weiping Ding
The direct oxidation of toluene by O 2 to benzaldehyde with high efficiency is a bright route for the green production of benzaldehyde but still a significant challenge. In this study, we develop a ligand modification strategy by bonding organophosphonic acid (OPA) to VTiO x /γ-Al 2 O 3 to restructure its interface microenvironment for enhancement of toluene oxidation to benzaldehyde. The as-prepared catalyst exhibits excellent selectivity over 99 % under mild conditions. Results of comprehensive characterizations and calculations reveal that the OPA bonding in bidentate with the V 6-coordinated species causes noticeable phase reconstruction between VO x and TiO 2 , thereby generating nearby new reactive oxygen species, which is responsible for the conversion of toluene to benzaldehyde at temperatures as low as ∼50 °C, much lower than that over VO x /TiO 2 (>130°C). The interface microdomain around the bonding site of OPA helps to significantly weaken the methyl C H bond of toluene molecule in reaction manifested as the significant decrease in apparent activation energy. Hence, the current work reveals a novel mechanism of the typical catalyst VO x /TiO 2 under OPA bonding, which is useful to solve the classic difficult reaction of toluene to benzaldehyde by O 2 oxidation.
研究领域:
催化化学
·
绿色化学
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产品关联
DOI
PubMed
高影响因子
HYDROMETALLURGY
·
2019
·
IF 3.465
Wenbo Lou,Yang Zhang,Shili Zheng,Ping Li,Ying Zhang,Yi Zhang,Bo Zhao,Zhefei Li,Wei Jin
China generates a large number of scrapped selective catalytic reduction (SCR) catalysts in the fossil fuel combustion plants every year. As a result, there is a giant quantity of 5 × 10 5 t scrapped V 2 O 5 -WO 3 /TiO 2 SCR catalyst annually worldwide, in which arsenic poisoning is a major cause of catalysts deactivation . In this study, a novel cleaner recovery process of alkaline-acid stepwise leaching was proposed for the high‑arsenic scrapped SCR catalysts to achieve excellent arsenic removal and structural reforming. It is found that arsenic can be completely removed from 1.92% to below the detection limit, and the surface area of regenerated catalysts is restored to 31 m 2 /g (similar to that of commercial catalysts). In the subsequent pickling and regeneration, Na + can be eliminated to obtain anatase-type TiO 2 for further activity recovery. Besides, valuable elements (W, V) have been successfully recycled by leaching the As-containing solid waste with ammonium salt. After replenishing active components, regenerated catalyst exhibits comparable activity with the commercial fresh catalyst, offering a promising method for scrapped catalyst recovery and further understanding of cleaner produces for waste management .
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 22
·10820-10828
·
IF 3.925
Die Hu,Weiquan Li,Ke Yin,Bichun Huang
Mn/TiO2 catalysts were synthesized using a deposition–precipitation method. Ru-doped Mn/TiO2 catalysts were prepared by an incipient-wetness impregnation method. To investigate the interaction between Ru and Mn species, the catalytic performance of Mn/TiO2 and Ru–Mn/TiO2 catalysts in the catalytic oxidation of chlorobenzene (CB) was evaluated. The physicochemical properties of the catalysts were characterized by XRD, HRTEM, XPS, EPR, H2-TPR, O2-TPD and so on. The results showed that the 0.8% Ru-10% Mn/TiO2 catalyst exhibited the best catalytic activity with 99% CB conversion at 250 °C and showed an excellent CO2 yield (95% at 300 °C) and stability. In comparison with the 10% Mn/TiO2 catalyst, the T90 of the Ru–Mn/TiO2 catalyst decreased by 60 °C, which was attributed to the interaction between Ru and Mn species at the interfaces of Ru/Mn. The Ru species increased the concentration of Mn4+ and Ru4+ and reduced the H2 reduction temperature, which was conducive to improving the redox performance of the catalysts. Ru species were highly dispersed on the Mn/TiO2 catalyst surfaces, forming a large number of Ru/Mn interfaces. The interaction between Ru and Mn species at the interfaces of Ru/Mn promoted the formation of oxygen vacancies and surface reactive oxygen species, thus enhancing the catalytic activity.
研究领域:
环境科学
·
催化化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）