POLYMER DEGRADATION AND STABILITY
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2016
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IF 3.12
Huali Xie,Xuejun Lai,Hongqiang Li,Xingrong Zeng
Fabricating an effective synergism between the condensed phase (char-forming) and the gas phase (free-radical quenching) is recently considered to be a very promising way to prepare high-efficient intumescent flame retardants . In this work, a novel hindered amine phosphorous-nitrogen macromolecular charring agent (HAPN) with free-radical quenching capability was synthesized and characterized. Then it was combined with ammonium polyphosphate (APP) to flame-retard polypropylene (PP). The flame retardancy and thermal stability of PP/HAPN/APP mixtures were investigated by limiting oxygen index (LOI), vertical burning test (UL-94), cone calorimetric test (CCT) and thermogravimetric analysis (TGA). When the content of HAPN/APP was 25 wt%, PP/HAPN/APP could self-extinguish at 36 s after igniting in the oxygen concentration of 29.5% and achieve a UL-94 V-0 rating. Meanwhile, the peak heat release rate (PHRR), total heat release rate (THR), average heat release rate (AV-HRR) and average mass loss rate (AV-MLR) were significantly decreased. The flame retardant mechanism of HAPN/APP was explored and the results revealed that there was an effective synergism between the condensed phase and the gas phase during the combustion. In the condensed phase, HAPN could make PP involve into the char-forming reaction to promote the formation of compact and firm intumescent char layer. Simultaneously, the nitroxyl radical generated by HAPN could effectively restrain and even extinguish the flame in the gas phase by quenching the active free-radicals.
研究领域:
高分子化学
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材料科学
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阻燃材料
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热稳定性
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燃烧性能
✓ 已验证
DOI
高影响因子
RSC Advances
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2017
·Vol. 7
·期 72
·45420-45431
·
IF 3.108
Jiuli Guo,Huanhuan Yu,Feng Dong,Baolin Zhu,Weiping Huang,Shoumin Zhang
A highly efficient and stable Au–Cu/hydroxyapatite (HAP, Ca10(PO4)6(OH)2) catalyst was reported. HAP was prepared through a deposition–precipitation method. Au–Cu/HAP catalysts were obtained by a two-step impregnation approach. The samples were characterized by XRD, TEM, SEM, UV-Vis, ICP, XPS, H2-TPR, and O2-TPD. CO oxidation reaction was carried out to evaluate the catalytic performance of samples. TEM and UV-Vis results showed that the metallic particles supported on Au–Cu/HAP were smaller than those on Au/HAP, and they were highly dispersed on the HAP support. Patterns of XPS revealed that CuO nanoparticles were formed in the Cu/HAP catalyst, while CuO and Cu2O species coexisted in Au–Cu/HAP catalyst. Based on the O2-TPD data, the addition of copper to Au/HAP gave rise to more new O2 adsorption sites and bigger O2 adsorption capacity. The catalysis results indicated that the Au–Cu/HAP was capable of obtaining higher efficiency and stability compared with Au/HAP and Cu/HAP for CO oxidation. It was likely that the synergistic interaction between gold and CuOx phase created the most active sites on Au–Cu/HAP and was responsible for the enhanced activity and stability in comparison with Au/HAP and Cu/HAP.
研究领域:
催化化学
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材料科学
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环境化学
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纳米催化
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表面科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2023
·
IF 6.2
Jing Jiang,Jiayi Zhang,Baihao Wu,Sheng Tu
The regulation of the metal-support interaction in heterogeneous catalysts can promote the activation of reactants, which is beneficial for the hydrolytic dehydrogenation reaction. Herein, the hydrolytic dehydrogenation of dimethylamine borane (DMAB) is systematically studied on the oxygen vacancy (O v ) enriched Pt-Co 3 O 4 heterogeneous catalyst with the metal-support interaction. It is found that the metallic Pt site facilitates the adsorption of DMAB molecules and the O v on Co 3 O 4 support as an electron-rich center cooperates with the adjacent Pt site to dissociate water molecules. The in situ Raman and attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy reveal the effective activation and cleavage of the O-H in water and the B-H in DMAB over the Pt-Co 3 O 4 catalyst. The optimal Pt-Co 3 O 4 catalyst exhibits the extraordinary activity for the catalytic hydrolysis of DMAB at 303 K, delivering a high specific hydrogen generation rate (64063 mL min −1 g pt −1 ) and a competitive turnover frequency (TOF, 23880 mol H2 mol Pt −1 h −1 ). This performance outperforms most of the reported heterogeneous catalysts for DMAB dehydrogenation . More importantly, the Pt-Co 3 O 4 catalyst achieves the desirable on-demand hydrogen production by using special chemical switches. This finding provides the fundamental understanding of metal-oxide systems with the collaborative interfacial catalysis for boosting DMAB dehydrogenation .
研究领域:
催化化学
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纳米材料科学
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能源化学
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表面科学
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多相催化
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氢能存储与释放
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
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2019
·
IF 7.723
Yuanyuan Ma,Zhongling Lang,Jing Du,Likai Yan,Yonghui Wang,Huaqiao Tan,Shifa Ullah Khan,Yang Liu,Zhenhui Kang,Yangguang Li
Selective reduction of nitroarenes is extremely valuable in industrial chemical production. The main reduced products are usually aniline derivatives obtained using single-component noble- or transition-metal catalysts; however, other important products such as hydrazobenzene derivatives always involve in harsh conditions and multiple reaction steps. Here, we realize an unexpected switchable reduction of nitroarenes into aniline or hydrazobenzene derivatives with high yield and selectivity just by controlling the molar ratio of nitroarenes to N 2 H 4 ·H 2 O with a nickel–tungsten carbide composite nanocatalyst loaded on carbon (Ni-WC/C). A series of control experiments and density functional theory (DFT) calculations indicate that the multiple interfaces between Ni and WC can induce a synergistic effect, significantly modulating the electronic structure of the Ni-WC/C catalyst, and endowing the catalyst with switchable selectivity and high activity for the reduction of nitroarenes by hydrogenation. This synergistic multi-interfacial catalyst may offer a new way to design and explore highly efficient and selective catalysts for the controllable reduction of nitroarenes and similar hydrogenation reactions.
研究领域:
催化化学
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有机合成
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纳米材料
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表面科学
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工业化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Jing Jiang,Wei Wei,Zhen Ren,Yang Luo,Xinzhi Wang,Ying Xu,Mingming Chang,Lunhong Ai
Developing efficient catalysts for the dehydrogenation of ammonia borane (AB) is important for the safe storage and controlled release of hydrogen, but it is a challenging task. In this study, we designed a robust Ru-Co 3 O 4 catalyst using the Mott-Schottky effect to induce favorable charge rearrangement. The self-created electron-rich Co 3 O 4 and electron-deficient Ru sites at heterointerfaces are indispensable for the activation of the B-H bond in NH 3 BH 3 and the O H bond in H 2 O, respectively. The synergistic electronic interaction between the electron-rich Co 3 O 4 and electron-deficient Ru sites at the heterointerfaces resulted in an optimal Ru-Co 3 O 4 heterostructure that exhibited outstanding catalytic activity for the hydrolysis of AB in the presence of NaOH. The heterostructure had an extremely high hydrogen generation rate (HGR) of 12238 mL min −1 g cat -1 and an expected high turnover frequency (TOF) of 755 mol H2 mol Ru -1 min −1 at 298 K. The activation energy needed for the hydrolysis was low (36.65 kJ mol −1 ). This study opens up a new avenue for the rational design of high-performance catalysts for AB dehydrogenation based on the Mott-Schottky effect.
研究领域:
催化化学
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能源材料
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纳米材料科学
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表面科学
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氢能源技术
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2018
·
IF 6.759
Xiaolong Liu,Qingzhen Han,Wenbo Shi,Cheng Zhang,Erwei Li,Tingyu Zhu
In this work, ruthenium-based bimetallic catalysts of 1Ru-5 M/TiO 2 (M = Co, Ce, Fe, Mn, Cu, Ni) were prepared and evaluated in ethyl acetate oxidation. It was found that 1Ru-5Cu/TiO 2 gave the highest catalytic activity. The influence of CuO content and the preparation method on the catalytic activity was also studied. 1Ru-5Cu/TiO 2 showed great catalytic stability in the on-stream reaction test. The influence of H 2 O on the catalytic activity is presented. The bimetallic catalyst 1Ru-5Cu/TiO 2 showed better catalytic performance than the monometallic catalysts 1Ru/TiO 2 and 5Cu/TiO 2 . XRD, TEM, HAADF-STEM, H 2 -TPR, and XPS characterizations were conducted, and the synergistic effect between Ru and Cu was well presented. In situ FTIR studies were also conducted, and the reaction intermediates were revealed on the catalyst surface. The theoretical calculations suggested that ethyl acetate is more easily adsorbed on the CuO surface, while it reacts more easily on the RuO 2 surface . Accordingly, a reaction mechanism for the catalytic oxidation of ethyl acetate over a Ru-Cu bimetallic catalyst is proposed.
研究领域:
催化化学
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环境化学
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表面科学
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材料化学
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物理化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
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2017
·
IF 6.395
Xiubo Xie,Ming Chen,Peng Liu,Jiaxiang Shang,Tong Liu
Nickel sulfides decorated reduced graphene oxide (rGO) has been produced by co-reducing Ni 2+ and graphene oxide (GO), and is subsequently ball milled with Mg nanoparticles (NPs) produced by hydrogen plasma metal reaction (HPMR). The nickel sulfides of about 800 nm completely in situ change to MgS, Mg 2 Ni and Ni multiple catalysts after first hydrogenation/dehydrogenation process at 673 K. The Mg-5wt%NiS/rGO nanocomposite shows the highest hydrogen desorption kinetics and capacity properties, and the catalytic effect order of the additives is NiS/rGO, NiS and rGO. At 573 K, the Mg-NiS/rGO nanocomposite can quickly desorb 3.7 wt% H 2 in 10 min and 4.5 wt% H 2 in 60 min. The apparent hydrogen absorption and desorption activation energies of the Mg-5wt%NiS/rGO nanocomposite are decreased to 44.47 and 63.02 kJ mol −1 , smaller than those of the Mg-5wt%rGO and Mg-5wt%NiS samples. The best hydrogen desorption properties of the Mg-5wt%NiS/rGO nanocomposite can be explained by the synergistic catalytic effects of the highly dispersed MgS, Mg 2 Ni and Ni catalysts on the rGO sheets, and the more nucleation sites between the catalysts, rGO sheets and Mg matrix.
研究领域:
材料科学
·
纳米科技
·
能源化学
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催化化学
·
储氢材料
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Xin Guan,Huijie Pei,Xiaoyu Chen,Chen Chang,Siyuan Shao,Yu-Mo Zhang,Xingping Zhou,Hui Nie,Xiaolin Xie
The adsorption-catalysis synergy for accelerated conversion of polysulfides is critical toward the electrochemical stability of lithium-sulfur battery (LSB). Herein, a non-metallic polymer network with anion receptor units, trifluoromethanesulfonyl (CF 3 SO 2 -) substituted aza-ether, was in-situ integrated on PE separator, working as an efficient host for anchoring lithium thiophosphates (LPS) as redox mediators and polysulfides through Lewis acid-base interaction. The anchored LPS on the modified PE separator displayed a robust chemical adsorption ability towards polysulfides through the formation of S S bond. Meanwhile, LPS decreased the energy barrier of Li 2 S nucleation and promoted redox reaction kinetics. The battery with LPS decorated separator revealed a long cycling lifespan with a per cycle decay of 0.056 % after 600 cycles, and a competitive initial capacity of 889.1 mAh/g when the of sulfur cathode increased to 3 mg cm −2 . This work developed a new design strategy to promote the utilization of lithium phosphorus sulfide compounds in LSB.
研究领域:
电化学
·
能源材料
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纳米材料
·
界面化学
·
储能技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）