MOLECULES
·
2024
·Vol. 29
·期 13
·2959
·
IF 4.2
Hejingying Niu,Jinhua Ma,Lina Gan,Kezhi Li
In this study, a PtSn/Al2O3catalyst with bimetallic uniform distribution in the sphere was synthesized. The PDH performance and characterization analyses, such as with FTIR, XPS, and NH3-TPD, were investigated. The effects of acid on the PDH performance were analyzed. Citric acid (CA) acted as a competing adsorbent in the preparation process of the PtSn/Al2O3catalyst to synthesize the uniform catalyst. Water washing and alkali-treated samples were also studied. SEM line scanning revealed that increased the apparent concentration of Pt metal from 0.23 to 0.30 with citric acid. In contrast to the fresh PtSn/Al2O3catalyst, the addition of citric acid increased the PDH selectivity from 74% to 93%. After alkali or water washing treatments, the catalyst’s selectivity further increased to 96%. Strong acid sites promoted the breaking of C–C bonds during the PDH reaction, resulting in more methane and ethylene byproducts, and decreased catalyst selectivity for fresh PtSn/Al2O3. From the PDH reaction thermodynamic analysis, a relatively sub-atmospheric pressure environment with a lower propane pressure could be the reasonable choice.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Hang Yu,Shanjun Mao,Bing Lu,Hao Wang,Xie Zhang,Menghui Qi,Ruiliang Gao,Yong Wang
Multicomponent reactions such as ammoxidation are highly desirable for chemical synthesis. The complicated reaction network and catalytic active sites involved, however, make it rather challenging for extensive structure–performance relationship investigations and subsequent rational design of an efficient catalyst. In this work, efficient VOx/TiO2 catalysts with concise components and exquisite structure design demonstrated 95% selectivity at 98% conversion under 2070 h–1 for 3-picoline ammoxidation. After clarifying that the oxidative dehydrogenation process is rate-limiting, we assumed that the abundance of reactive surface lattice oxygen at the interface of vanadium–titanium is the key to high productivity and suppression of oxidation side reactions since low reaction temperature is beneficial for enlarging the difference in rates of different energy barriers. In addition, rather than applying the traditional neutralization method with alkaline components, in situ formed V2O5 crystallite was subtly to cover the strong acid sites on VOx/TiO2 catalysts in that the strong adsorption of pyridine nitrogen in 3-cyanopyridine on strong acid sites can lead to severe hydrolysis side reactions.
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
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
In this paper, the Cu-Ce based catalyst using NbOPO 4 (Nb-P) as support was firstly employed for selective catalytic reduction (SCR) of NO by NH 3 . The experimental results had illustrated that such catalyst exhibited well SCR activity and N 2 selectivity within a wide temperature range of 200–450 °C. These superior performances could be mainly attributed to its improved textural properties and strong acidity derived from NbOPO 4 support. More importantly, the sulfur tolerance of the NbOPO 4 supported Cu-Ce sample was found greatly improved compared to TiO 2 and Ti-Nb supported samples, where above 80% SCR activity of Cu-Ce/Nb-P sample was obtained at 250 °C after 10 h reaction running in the presence of 100 ppm SO 2 . This fact was the result of the enhanced acidity and the strong interactions between Cu-Ce oxides and NbOPO 4 support, which could prevent the surface oxygen species from sulfation by SO 2 . As such, these oxygen species strongly associated with NbOPO 4 support still could activate adsorbed NH 3 to fulfill the SCR reaction cycle, leading to its better sulfur resistance. The work would provide some enlightenments to the development of NH 3 -SCR catalysts with high sulfur resistance at medium-high temperature.
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
FUEL
·
2018
·
IF 4.908
Zhong-Qiu Liu,Xian-Yong Wei,Fang-Jing Liu,Guang-Hui Liu,Zhi-Min Zong
Trifluoromethanesulfonic acid supported on attapulgite powder (TFMSA/AP) and Mg 2 Si/γ-Al 2 O 3 were facilely prepared by impregnating TFMSA onto AP and Mg 2 Si onto γ-Al 2 O 3 . The extraction residue from Yiwu lignite (YL ER ) was subjected to non-catalytic hydroconversion (NCHC) and catalytic hydroconversion (CHC) over TFMSA/AP and Mg 2 Si/γ-Al 2 O 3 , respectively. Detailed molecular compositions of the soluble portions from the NCHC (SP NCHC ) and CHC over TFMSA/AP (SP CHC-A ) and Mg 2 Si/γ-Al 2 O 3 (SP CHC-B ) were characterized with a gas chromatograph/mass spectrometer. As a result, the yields of SP CHC-A and SP CHC-B are 19.6% and 17.5%, respectively, which are much higher than that of SP NCHC (1.04%), suggesting that both TFMSA/AP and Mg 2 Si/γ-Al 2 O 3 show excellent activity for the CHC of YL ER . Arenes and arenols are predominant in SP CHC-A and SP CHC-B , respectively, while large amounts of alkanoates were detected in SP NCHC . The results indicate that TFMSA/AP effectively catalyzes the cleavage of C ar –C alk and C alk –O bridged bonds (BBs) in YL ER , while Mg 2 Si/γ-Al 2 O 3 significantly promotes the cleavage of C–O BBs in YL ER . Di(1-naphthyl)methane, 1-methylnaphthalene, oxydibenzene, and benzyloxybenzene were used as coal-related model compounds (CRMCs) for the CHC to further explore the catalysis of TFMSA/AP and Mg 2 Si/γ-Al 2 O 3 . The results show that TFMSA/AP not only releases mobile H + but also heterolytically splits H 2 to form an immobile H − and a mobile H + , leading to the cleavage of C alk –C ar and C alk –O BBs in the CRMCs. In contrast, Mg 2 Si/γ-Al 2 O 3 facilitates heterolytically splitting H 2 to an immobile H + and a mobile H − , resulting in the cleavage of C–O BBs in the CRMCs.
研究领域:
化学工程
·
煤炭化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Jun Zhang,Chengyu Li,Jing Gu,Haoran Yuan,Yong Chen
This study aimed to investigate the co-pyrolysis characteristics of strong-acid cation exchange resin (Amberlyst-15, denoted as A15) and cellulose (CE), in which the existing synergistic interaction effects were uncovered. Crucial variables including pyrolytic temperature, A15-to-CE mass ratio and heating rate were taken into consideration. The levoglucosenone (LGO) production from CE and inorganic sulfur-containing species release from functional sulfonic acid groups of A15 were enhanced in a temperature range of below 400 °C. In this regard, the LGO yield achieved approximately 7 wt% at 300 °C with A15-to-CE mass ratio of 1:1. Relatively, elevating the temperature and heating rate accelerated the A15 self-decomposition and small molecule fragments restructuring to give much more monocyclic and polycyclic aromatics. Noticeably, organic sulfur-containing compounds also were produced in an unignorable amount of 8.2% under preset conditions of pyrolytic temperature of 700 °C and heating rate of 20,000 °C/s. The plausible pathway for the co-pyrolysis transformation of A15 and CE was also proposed on the basis of experimental results. The present work will provide a probable and feasible strategy for the high-value utilization of biomass and waste ion-exchange resins, particularly in the aspect of the generation of certain chemicals.
研究领域:
能源与燃料
·
环境科学
·
生物质转化
✓ 已验证
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 64
·34161-34167
·
IF 3.708
Wenpeng Ding,Juan Li,Kang Tao
Solid super acid (SSA) as a kind of green catalyst was introduced into conventional intumescent flame retardant (IFR)/ethylene-vinyl acetate (EVA) composites to increase their flame retardant efficiency. The IFR used was a combination of ammonium polyphosphate coated by melamine resin (MAPP) and pentaerythritol (PER) with weight ratio at 3 : 1. TGA results showed that the SSA promoted the reaction between MAPP and PER. The thermal degradation temperature of the IFR/EVA composites with 1.5 wt% SSA was significantly increased by 95 °C compared to that of IFR/EVA. The UL 94 V-0 rating can be achieved for EVA composites with 13 wt% total amount of IFR and SSA, while the EVA composites with individual 13 wt% IFR only passed the UL-94 V-2 rating. The char residues at 800 °C of SSA/IFR/EVA composites were 5.8 wt%, which was higher than 2.4 wt% of IFR/EVA composites. Many carbon microspheres were observed by SEM which were deposited in the char matrix after the cone calorimeter test. These carbon microspheres had better graphite structure, thus the char was strengthened and could resist more heat and gas flow erosion. The synergistic effect between the gas phase and condensed phase was considered the main factor for the increase of flame retardant properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2016
·
IF 2.75
Chen-Hao Ji,Shuang-Mei Xue,Zhen-Liang Xu,Xiao-Hua Ma
In this work, a novel hollow fiber catalytic packing (HFCP) was fabricated of ZrO 2 (shell)/TiO 2 (core) (TZ) solid superacid nanoparticles , perfluorinated sulfonic acid resin (PFSA) and polyethersulfone (PES) via wet-spinning method. TZ was a homemade binary solid superacid nanoparticles with core–shell structure using superfine titania (5 nm) as the core and mesoporous tetragonal phase zirconia as the shell. It was synthesized through the hydrolysis of zirconium oxychloride in the presence of titania nanoparticles and cetyltrimethylammonium bromide (CTAB) hexagonal crystals covered on the titania core and followed by calcination and acidification. HFCPs demonstrated well catalytic performance in the esterification test of ethanol and acetic acid due to the superacid sites on the surface of TZ and PFSA polymer chain. And the superacid sites on the PFSA polymer chain could be sufficiently exposed by the embedding of the nanoparticles. At the same time, HFCPs also showed ultrahigh recovery which was more than 99.5% in 6 runs because of the well integrality benefited from the wet-spinning method. The specific surface area (SSA) and pore size distribution were analyzed by N 2 adsorption–desorption, the result showed that the SSA of HFCPs decreased with the increasing of the PFSA additive amount. The SSA of the HFCP with the best catalytic performance could be up to 90.60 m 2 /g, in which the PFSA weight proportion was 13%. The XRD pattern and HRTEM image showed the HFCPs i.e. the zirconia shell of TZ formed uniform tetragonal phase. Other characterizations such as FT-IR, XPS, SEM and TEM were utilized to determine the chemical composition and morphology of the HFCPs and TZ, the results showed the novel catalytic packing was a suitable catalyst for the acid catalyzed reactions.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 56
·50630-50639
·
IF 3.289
Xiaoqin Fu,Xiaoli Sheng,Yuming Zhou,Zhiwei Fu,Shuo Zhao,Xiaohai Bu,Chao Zhang
Hierarchical zeolite Y was hydrothermally synthesized using ionic liquid 1-methyl-3-[3′-(trimethoxysilyl)propyl]imidazolium chloride, which was added into the conventional synthesis composition for crystalline microporous aluminosilicate as a mesopore-directing agent. An extremely short diffusion path length and abundant exposed acid sites in the hierarchical zeolite Y made it suitable for the catalytic transformation of bulky molecules. Then the catalytic performance of hierarchical zeolites Y was investigated using the alkylation of o-xylene with styrene. The ionic liquid directed hierarchical zeolite Y exhibited a remarkably high catalytic activity and long catalytic lifetime for the production of 1-phenyl-1-xylylethane via alkylation reaction, as compared with that of solely microporous zeolite Y. The distinct catalytic performances of the novel hierarchical zeolite Y could be attributed to the enhancement of medium strong acid amount and its micro–mesoporous structural properties which are favorable for the fast diffusion of products.
研究领域:
催化化学
·
材料科学
·
石油化工
✓ 已验证
产品关联
DOI
高影响因子
TRANSACTIONS OF TIANJIN UNIVERSITY
·
2018
·Vol. 25
·期 2
·143-151
·
IF 0
Du Jianzeng,Li Yonghong,Miao Zhenyu
Novel Ni/ZnO – HZSM-5 adsorbents were synthesized by incipient wetness impregnation. The Ni/ZnO – HZSM-5 adsorbent can achieve deep desulfurization and olefin aromatization at the same time. Thiophene sulfur was removed from 495 to less than 10 ppm via reactive adsorption desulfurization (RADS). Olefins were also converted into aromatics. HZSM-5 did not only support adsorbents but also cooperated with active Ni sites to catalyze olefins into aromatic hydrocarbons. Aromatization of 1-pentene, 2-pentene, 2-methyl-2-butene, and 1-hexene on adsorbents was investigated. The adsorbents were characterized by the Brunauer–Emmett–Teller, X-ray diffraction, temperature-programmed reduction, and temperature-programmed desorption of ammonia and thermogravimetric analysis. The experimental results showed that strong acids on the adsorbent disappeared after HZSM-5 loaded active metal sites, and almost no coke was generated on adsorbents in RADS.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
JOURNAL OF POROUS MATERIALS
·
2019
·Vol. 27
·期 2
·429-440
·
IF 1.947
Wang Yunjie,Yuan Hong,Zhang Zhi,Ke Yihu
A series of ordered mesoporous S 2 O 8 2−/ ZrO 2 –SiO 2 (OMSZS) solid superacids with different calcination temperatures (400–650 °C) was synthesized using zirconium n-propoxide and tetraethyl orthosilicate as the raw materials and P123 as a structure-directing agent by solvent evaporation-post-dipping method. Transmission electron microscopy and small-angle X-ray diffraction results showed that the OMSZS were all ordered. The nitrogen adsorption results indicated that the specific surface area of OMSZS could reach up to 331–385 m 2 /g, whereas the average pore diameters were in the range of 3.1–3.2 nm. The pyridine infrared results mainly displayed Lewis acids, and the ammonia (NH 3 )-temperature programmed desorption characterization showed that the NH 3 desorption of the OMSZS calcined at 550 °C was 61 cm 3 /g STP. The catalytic performance of the OMSZS was investigated by the transesterification reaction of waste frying oil and methanol. The yield of fatty acid methyl ester could reach up to 94% at 200 °C reaction temperature for 6 h. After repeated use for four times, the catalyst still featured good activity and the yield was 78%.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Water Process Engineering
·
2024
·
IF 6.3
Shuang Fu,Yingbo Chen,Xintong Wu,Liu Ye,Linzhe Xu,Xinyu Zhao
Nanofiltration (NF) membranes play a crucial role in wastewater treatment based on their unique separation mechanism. However, conventional polyamide nanofiltration membranes are susceptible to degradation in extreme pH or chlorine environments, resulting in a limited range of applications. In this study, hydrophilic functional coatings were constructed on polyethersulfone (PES) support using the biopolymer materials, κ-carrageenan (κ-CGN) and sodium carboxymethyl cellulose (CMC). The coatings were cross-linked with glutaraldehyde (GA) to form a dense three-dimensional network structure insoluble in water, enabling structural stability in harsh environments. The Na 2 SO 4 retention of the κ-CGN/CMC/PES composite membranes was maintained at 92.1 and 91.4 % after 38 days of immersion in 20 wt% H 2 SO 4 and 2 M NaOH aqueous solutions, respectively. Meanwhile, κ-CGN/CMC/PES maintained a good salt retention (Na 2 SO 4 , ∼90.0 %) after chlorine treatment (72,000 ppm h). The excellent separation performance of the κ-CGN/CMC/PES composite membranes at different pH and concentration of Cr (VI) indicated its wide application for Cr(VI) removal at harsh conditions.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
·
2024
·Vol. 41
·期 3
·809-819
·
IF 1.8
Longwen Yang,Longwen Yang,Aochen Du,Aochen Du,Xingke Zheng,Xingke Zheng,Yun Ye,Yun Ye,Enguo Chen,Enguo Chen,Sheng Xu,Sheng Xu,Tailiang Guo,Tailiang Guo
All-inorganic perovskite quantum dots (PQDs) have excellent photoelectric performance, such as high photoluminescence quantum yield (PLQY), narrow full width at half-maximum (FWHM), and emission spectra covering the visible light wavelength. The emission color can be tuned over the full visible spectral region making them promising for white-light-emitting diodes (WLEDs). Further control over the optical and magnetic properties of PQDs can be achieved through doping of transition metal ions such as ${{\rm Mn}^{2 +}}$ ions. In this paper, a rapid doping method is employed at room temperature by using strong-acid cation-exchange resin during the metal ions doping process, which shortens the doping time, and ${\rm Mn}{:}{\rm CsPb}{({\rm Cl}/{\rm Br})_3}$ QDs were obtained. By controlling the reaction time between strong-acid cation-exchange resin and PQDs, we achieve different levels of manganese doping, resulting in a new, to the best of our knowledge, fluorescence peak at 600 nm. The introduction of strong-acid cation-exchange resin preserves the integrity of the PQD structure, while completing the doping within 30 min. Due to the low cost and mild reaction conditions of resin, it is expected that the ${\rm Mn}{:}{\rm CsPb}{({\rm Cl}/{\rm Br})_3}$ QDs can be mass-produced in large quantities. In addition, in order to provide high-quality white light emission, and prevent anion exchange reactions when mixed with ${{\rm CsPbBr}_3}$ QDs, the ${{\rm CsPbBr}_3}$ QDs are coated with silicon. Finally, by combining ultraviolet-light-emitting diodes (UVLEDs) with the aforementioned PQD mixture, this paper successfully fabricates WLEDs and demonstrates its excellent photoelectric performance. The constructed WLEDs produce warm white light with a high color rendering index (CRI) of 91 and a high correlated color temperature (CCT) of 5966 K, and the luminous efficacy (LE) of WLEDs is ${41}\;{{\rm lmW}^{- 1}}$.
研究领域:
材料科学
·
光电技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）