查找使用阿拉丁产品的科研文献

Synergistic enhancement of size and electronic effects in Ni-based catalysts via Ni–Al interfacial interaction modulation for N-ethylcarbazole hydrogenation

Shiyuan Wang,Peiya Li,Shuhan Lu,Bo Wang,Qinchuan Shi,Jiahui Wang,Fusheng Yang,Bin Wang,Tao Fang

Developing both high-performance and cost-effective hydrogenation catalysts is of strategic importance for advancing the industrialization of liquid organic hydrogen carrier (LOHC) technology. Herein, a series of Ni-based catalysts supported on Ni/Al mixed metal oxides (Ni/NiAl-MMO) are prepared by in-situ topotactic transformation of NiAl-LDH precursors. The synergistic enhancement mechanism, which is regulated by the Ni–Al interfacial interactions and the anchoring effect of precursors, is systematically investigated with respect to the influence on the size and electronic structure of active metal nanoparticles, as well as on the catalytic performance in N-ethylcarbazole (NEC) hydrogenation. The results show that the optimized Ni/Ni 1 Al 2 -MMO-500 catalyst achieved both small size and high electron density of active metal particles. The synergistic size and electronic enhancement endow the catalyst with superior catalytic activity in NEC hydrogenation, exceeding all reported Ni-based catalysts and exhibiting catalytic efficiency comparable to that of the widely used commercial precious metal hydrogenation catalyst, 5 wt% Ru/Al 2 O 3 , with high catalytic performance sustained across five NEC hydrogenation cycles.

Filiform Corrosion Inhibition of Zn–Al–Mg-Coated Steel by Ti–Zr Conversion Coating: Crucial Role of Benzotriazole-5-Carboxylic Acid

Haiqing Liu,Muhammad Jawad,Jingmao Zhao,Baomin Fan,Mohammad Tabish,Muhammad Mubeen,Mubashar Mahmood,Jingbao Wang

Under-film filiform corrosion (FFC) poses a significant challenge to the durability and reliability of Zn–Al–Mg-coated steel (ZM-steel), necessitating the development of advanced protective strategies. Herein, benzotriazole 5-carboxylic acid (BTC)-modified titanium zirconium (TiZr) conversion coatings (CCs) were developed as a sustainable solution to mitigate FFC, enhance corrosion resistance, and improve the adhesion of epoxy (EP) coatings on ZM-steel. Through electrochemical impedance spectroscopy, potentiodynamic polarization, FFC, and neutral salt spray (NSS) tests, the optimized BTC-TiZr CC, prepared in a Ti–Zr solution containing 0.5 g/L BTC, a treatment temperature of 25 °C, and a short immersion duration of 120 s, exhibited superior corrosion resistance, robust adhesion strength, and exceptional FFC inhibition. Metal–organic complexes (MOCs) of Ti/Zr/Zn with BTC were identified alongside mixed Ti/Zr/Zn/Al/Mg oxides and fluorides within the BTC-TiZr CC. BTC not only exerted strong corrosion inhibition efficacy for ZM-steel but also facilitated the formation of MOCs with metal ions in TiZr conversion solutions (CSs). Density functional theory calculations revealed that BTC preferentially adsorbs onto the MgZn2 phase, effectively suppressing its dissolution within the ZM layer. These findings establish BTC-TiZr CCs as a promising, environmentally friendly solution for advanced corrosion protection of ZM-steel, especially FFC suppression.

Insight into the impact of the Al distribution in ZSM-5 zeolite on deep hydrogenation of phenanthrene over Pt/HZSM-5

Chuan-Hao Zhang,Qi Dong,Fei Wang,Ning-Yue Lu,Feng Yu,Bin-Bin Fan,Rui-Feng Li

Deep hydrogenation of polycyclic aromatic hydrocarbons (PAHs) into jet fuel is an important strategy for the upgrading of light cycle oil (LCO). Zeolite-supported metal catalysts have exhibited good catalytic performance for hydrogenation of PAHs under relatively mild conditions. However, the impacts of acidity variations in zeolite supports, arising from the differences in framework Al (Al F ) distribution on the catalytic behavior of zeolite-supported metal catalysts in the deep hydrogenation of PAHs remains unclear. Herein, two series of mesoporous ZSM-5 samples, that is ZSM-5-E- x and ZSM-5-F- x , with the differences in Al F distribution but similar Si/Al ratios, were prepared in the crystallization system with or without NaOH. The results of NH 3 -TPD, Pyridine-IR, N 2 adsorption-desorption and SEM reveal that two series of HZSM-5 samples have similar acid density and acid strength, textural properties, morphology and particle size. However, the results of XPS, 27 Al MAS NMR, 2,6-Ditert-butylpyridine-IR, catalytic cracking of 1,3,5-triisopropylbenzene and the controlled reactions as well as DFT calculation indicate that the higher enrichment degree of Al F on the external surface and the suitable arrangement mode of Al F in ten-membered ring (10-MR) of HZSM-5-F- x compared to HZSM-5-E- x in case of the similar Si/Al ratios, result in Pt/HZSM-5-F- x exhibiting remarkably-improved deep hydrogenation performance of phenanthrene (PHE) compared to Pt/HZSM-5-E- x . Particularly, the selectivity to perhydrophenanthrene (PHP) over Pt/HZSM-5-F-50 can reach above 99.0% at a conversion of PHE (>99.0%). Furthermore, Pt/HZSM-5-F-50 exhibits well reusability. This work helps to clarify the impact of Al F distribution in ZSM-5 on catalytic hydrogenation performance for PAHs, providing valuable guidance for design and development of efficient catalysts for the hydrogenation of PAHs.

The EALD-Al2O3/CTPEN composite films with Al-O-C chemical bonding exhibit enhanced moisture barrier and mechanical properties for encapsulation

Yunle Yao,Rui Pan,Hua Cheng,Yi Gong,Lin Chen,Xian Zhang,Meng Xue,Xingyou Tian

Encapsulation is a crucial technology for isolating and protecting moisture-sensitive materials. However, traditional organic-inorganic composite films often exhibit poor adhesion at the interface and high gas permeability, making stable operation difficult. In this work, an enhanced atomic layer deposition (EALD) method was used to uniformly deposit a layer of thickness-controlled alumina on a Polyethylene Naphthalate (PEN) film with oxygen-containing polar groups(CTPEN) on its surface, successfully producing a high-barrier composite film (EALD-Al 2 O 3 /CTPEN) with Al-O-C chemical bonds. The designed CTPEN film significantly enhanced the adhesion of alumina, thereby improving the performance of the composite film. Moreover, the mechanical properties of the composite film were significantly enhanced, with the elongation at break of EALD-Al 2 O 3 /CTPEN at 72 % being considerably higher than that of ALD-Al 2 O 3 /PEN at 44 %, and the tensile strength reaching 220 MPa. At the same time, EALD-Al 2 O 3 /CTPEN maintained excellent light transmission, exceeding 85 %. Humidity -sensitive resistors encapsulated with EALD-Al 2 O 3 /CTPEN exhibited stable operating performance in both air and humidity-sensitive environments, confirming the superior barrier properties of the composite film. This EALD-Al 2 O 3 /CTPEN composite layer holds promise as a prospective encapsulation layer for future flexible devices.

Regulating Si/Al Role of MCM-41 with Graphite Carbon-Coated Co NPs for Efficient Hydrogenation of Furfural to Furfuryl Alcohol

Zhouxiao Zhai,Jingce Bi,Yi Wang,Ningning Liu,Linshan Wang,Xia Zhang,Zhuopeng Wang,Yide Han

Graphical In this work, a mesoporous molecular sieve with graphite carbon-coated Co NPs (Co@CN/Al-MCM-41) was successfully synthesized by vacuum-injecting the precursor solution into the MCM-41 molecular sieve and subsequent calcination. Experimental results demonstrate that Co@CN/Al0.1-MCM-41 exhibits excellent catalytic performance in the hydrogenation of FF. Its excellent catalytic performance is primarily attributed to the interaction between Co species and Al species of MCM-41, including the reduction effect, electron transfer, and enhancement of acid density. The catalytic hydrogenation of furfural (FF) to furfuryl alcohol (FOL) using metal-loaded mesoporous molecular sieves represents a significant research area. In this work, a mesoporous molecular sieve with graphite carbon-coated Co NPs (Co@CN/Al-MCM-41) was successfully synthesized by vacuum-injecting the precursor solution into the MCM-41 molecular sieve and subsequent calcination. Using Co@CN/Al 0.1 -MCM-41 as the catalyst, the selective hydrogenation of FF to FOL achieved a conversion rate of 91.2% under mild conditions at 120 °C, which is 2.85 times higher than that of Al-free Co@CN/MCM-41, with an FOL selectivity of 97.2%. The experimental results revealed a strong correlation between FF conversion and the Si/Al ratio of MCM-41 molecular sieve. Increasing the Al species content facilitated the formation of more Co NPs active sites because of the strong electrostatic interaction, thereby promoting the activation of FF and hydrogen and enhancing the catalytic activity of Co@CN/Al 0.1 -MCM-41. Additionally, Co@CN/Al 0.1 -MCM-41also exhibited stable performance over five consecutive cycles, which was attributed to the formation of graphite carbon-coated Co NPs structure during the synthesis process. This simple fabrication strategy provides a novel approach for the modification of mesoporous molecular sieves with excellent catalytic activities.

Reinforcement and reconfiguration of framework Al in P@ZSM-5 zeolite via in-situ phosphating strategy for efficient methanol-to-propylene

Yimin Zhang,Yun Zu,Ke Yan,Yuan Zhu,Yibin Luo,Enhui Xing,Qiang Li,Lijuan Song,Tan Li,Yi Mei,Xingtian Shu

In this work, a "bottom-up" strategy was proposed to one-step, in-situ synthesize P@ZSM-5 zeolites in a sodium-free system by elaborately self-designed tetrapropylphosphonium hydroxide as a new member of MFI-type zeolite organic templates inventory, and the interaction of phosphorus species with framework aluminum was investigated in detail. Multiple advanced characterizations confirm that the tetrahedrally-coordinated bidentate P IV -O 2 -Al IV structures are precisely customized and uniformly scattered in the zeolite channels. After experiencing harsh hydrothermal treatment (100 %H 2 O, 800 °C, 17 h), this new structure endows excellent hydrothermal stability of zeolite (crystallinity retention beyond 95 %) and reinforces its Brønsted acidity. Furthermore, methanol-to-propylene tests show that directly synthetic P@ZSM-5 zeolite performs extraordinarily long lifetime (180 h, WHSV = 1 h −1 ), enviable propylene selectivity (60.4 %) and propylene/ethylene ratio ( ca. 4.3) compared to the counterparts, which is benefited from encouragingly olefinic cycle pathway. These findings afford value-filled opportunities in novel catalyst production mode and understandings for phosphorus-zeolite chemistry . Synopsis -A "bottom-up" strategy was demonstrated to one-step, in-situ synthesize P@ZSM-5 zeolite in a sodium-free system by elaborately self-designed tetrapropylphosphonium hydroxide. The resultant P@ZSM-5 catalyst with hyperuniformly-stable bidentate P IV -O 2 -Al IV structures exhibited extraordinarily long lifetime (180 h) and enviable propylene selectivity (60.4 %).

Preparation of Ti3SiC2-based diamond composites by Ni–Al assisted self-propagating reaction of Ti–SiC–C system in microwave field

Mian Yang,Kaihua Chen,Shenghui Guo,Ming Hou,Jiyun Gao,Junwen Zhou,Shuhao Shi,Li Yang

In this paper, the self-propagating reaction of the Ti–SiC–C system for synthesising Ti 3 SiC 2 -based diamond composites is ignited by the combustion of Ni–Al alloy powders in a microwave field. The heating curves of Ni–Al-assisted microwave sintering show that the self-propagating reaction could be successfully ignited after heating samples to 685.2 °C in a microwave field for 456 s. This finding indicates that ignition could occur at temperatures below the diamond graphitisation temperature (727 °C). X-ray diffraction analysis indicates that the sintered samples primarily comprise Ti 3 SiC 2 , TiC, Ti 5 Si 3 and C. Scanning electron microscopy coupled with energy dispersive spectroscopy observations demonstrates that the diamond grains are tightly bonded with the surrounding matrix and are intact. The best wear ratio of 302.26 was obtained for the Ti 3 SiC 2 -bonded diamond composite when the diamond grain size was 140/170 mesh and the molar ratio of Ti, SiC and C was 3:1.1:0.9.

Synthesis of microcrystalline brownmillerite Ca2(Al,Fe)2O5 and its influence of mechanical properties to the class G oil-well cement

Xiaowei Cheng,Yongsheng Yang,Yongqiang Yang,Kaiqiang Liu,Kaiyuan Mei,Zaoyuan Li,Xiaoyang Guo,Wenhui Duan

The effect of Si/Al ratio on the catalytic performance of hierarchical porous ZSM-5 for catalyzing benzene alkylation with methanol

Hualei Hu,Jinghui Lyu,Jiayao Rui,Jie Cen,Qunfeng Zhang,Qingtao Wang,Wenwen Han,Xiaonian Li

Ethylbenzene is the major side product in benzene alkylation with methanol and it is difficult to be suppressed over hierarchical porous ZSM-5. Moreover, the separation of ethylbenzene from xylene still remains a great challenge. Our research indicated that ethylbenzene formation could be highly suppressed by changing the Si/Al ratio of the catalyst. Hierarchical porous ZSM-5 catalysts with different Si/Al ratios were prepared via reducing the amount of Al in the solvent evaporation assisted dry gel conversion method. In this method, tetra-n-propylammonium hydroxide was used as the direct agent to create micropores, and hexadecyltrimethoxysilane was added to create additional porosities by forming organic assemblies which occupied a certain space between zeolitic walls. The catalyst with a Si/Al ratio of 1800 could achieve high benzene conversion (59.5%) and high xylene selectivity (39.0%) as well as excellent suppression of ethylbenzene formation (<0.1%).

Ni single atoms anchored on nitrogen-doped graphene as H2-Evolution cocatalyst of SrTiO3(Al)/CoOx for photocatalytic overall water splitting

Yuxiang Liu,Xuejun Xu,Sufan Zheng,Shangchun Lv,Hewen Li,Zhichun Si,Xiaodong Wu,Rui Ran,Duan Weng,Feiyu Kang

Aluminum-doped strontium titanate SrTiO 3 (Al), has been demonstrated as the suitable photocatalyst for overall water splitting. Noble metals, such as RhCrO x , are widely applied to accelerate the photocatalytic hydrogen evolution . Herein, Ni single atoms anchored on nitrogen-doped graphene (Ni SA-NG) are adopted to replace noble metal as hydrogen (H 2 ) evolution cocatalysts for SrTiO 3 (Al)/CoO x photocatalyst. The prepared Ni SA-NG/SrTiO 3 (Al)/CoO x photocatalyst exhibits remarkable activity for photocatalytic overall water splitting with the H 2 evolution rate of 498 μmol g −1  h −1 and oxygen (O 2 ) evolution rate of 230 μmol g −1  h −1 , respectively. Ni SA-NG not only improves the efficiency of photogenerated charge transfer and separation through the Ti–O–C bonds acting as the electron transfer freeway, but also provides highly active sites to accelerate the surface H 2 evolution rate. This research provides a valuable method to construct SrTiO 3 -based photocatalyst without noble metal cocatalysts.

Comparative Study of M(Ⅱ)Al (M=Co, Ni) Layered Double Hydroxides for Silicone Foam: Characterization, Flame Retardancy, and Smoke Suppression

Lin-Lin Zhou,Wen-Xiong Li,Hai-Bo Zhao,Bin Zhao

To compare the different actions of the two representative transition metal cations of Co2+and Ni2+in layered double hydroxides (LDHs), CoAl-LDH and NiAl-LDH intercalated with CO32−were synthesized, and the chemical structures, microstructures, and surface areas thereof were successfully characterized. Then, the two LDHs were utilized as flame retardants and smoke suppressants for silicone foam (SiF). The densities, flame retardancy, smoke suppression, thermal stabilities, and compressive strengths of the two SiF/LDHs nanocomposites were investigated. The introduction of LDHs slightly decreased the density of SiF due to the catalytic actions of Co and Ni during the foaming process of SiF. With respect to the flame retardancy, the addition of only 1 phr of either CoAl-LDH or NiAl-LDH could effectively improve the limiting oxygen index of SiF from 28.7 to 29.6%. Based on the results of vertical flame testing and a cone calorimeter test, the flame retardancy and fire safety of the SiF were effectively enhanced by the incorporation of LDHs. In addition, owing to the good catalytic action and large specific surface area (NiAl-LDH: 174.57 m2g−1; CoAl-LDH: 51.47 m2g−1), NiAl-LDH revealed higher efficiencies of flame retardancy and smoke suppression than those of CoAl-LDH. According to the results of energy-dispersive X-ray spectroscopy, Co and Ni participated in the formation of protective char layers, which inhibited the release of SiO2into the gas phase. Finally, the influences on the thermal decomposition and compressive strength for SiF resulting from the addition of LDHs are discussed.Keywords:silicone foam;layered double hydroxides;transition metal;flame retardancy;smoke suppression

Inner-filter effect induced fluorescent sensor based on fusiform Al-MOF nanosheets for sensitive and visual detection of nitrofuran in milk

Xiaoyue Yue,Zijun Zhou,Min Li,Mingsha Jie,Baocheng Xu,Yanhong Bai

Developing highly sensitive and visual methods for rapid detection of antibiotics is significant to ensure food quality and safety. To meet the requirement of nitrofuran antibiotics detection, luminescent fusiform Al(III)-containing metal–organic frameworks (Al-MOF) nanosheets were successfully synthesized by one-step hydrothermal method. And then, the nanosheet served as a fluorescent probe to detect nitrofuran via the inner-filter effect mechanism. The developed sensor allowed sensitive and selective detection of nitrofuran with good linear relationships. And, the detection limit (LOD) values were estimated to be 0.53, 0.838 and 0.583 μM for nitrofurazone, nitrofurantoin and furazolidone detection, respectively. The practical application of the proposed system was verified by HPLC in spiked milk samples with satisfying recoveries ranging from 88.14 to 126.21% and low relative standard deviations of 2.85 ~ 8.13%. Moreover, we designed fluorescent test papers for semi-quantitative detection of nitrofuran via naked-eye colorimetric assay. The established method provides an alternative strategy for semiquantitative detection of nitrofuran.