查找使用阿拉丁产品的科研文献

Anodic Dissolution Behavior of Zirconium in n-Butanol Solutions Containing Bun4NBr

Xiyun YANG,Ling RAN,Shenghai YANG

Anodic dissolution of zirconium in Bun4NBr-containing n-butanol solutions was investigated using cyclic voltammetry, linear sweep voltammetry and potentiostatic current–time transient and scanning electron microscopy (SEM). Zirconium did not exhibit active dissolution due to passivation in the potential region of 0.2 to 1.2 V vs. SCE. The zirconium dissolution in passive state was under mass transfer control. Pitting corrosion took place as a result of passivity breakdown by Br− anions and the typical steady-state pitting potential was between 1.55–1.60 V vs. SCE in n-butanol solutions containing 0.08 M Bun4NBr. SEM images confirmed the occurrence and the intensification of pits with an increase of potential. Increasing Bun4NBr concentration accelerated the pit nucleation and growth. The reaction order leading to pit nucleation process was 1.0 with respect to bromide anions. The dissolution of zirconium in n-butanol solution produced Zr(OC4H9)4.

Homopolymerization and copolymerization of N-substituted maleimides with chiral anionic initiators

Yi-Ling Huang,Jing Cao,Wei Hu,Sai Liang

Novel optically active anionic initiators bearing a chiral oxazole substituent on the fluorene ring, ( S )-1-(9H-fluoren-2-yl)-4-isopropyl-4,5-dihydrooxazole lithium (Li-( S )-1-FIDH) and ( S )-2-(9H-fluoren-2-yl)-4-isopropyl-4,5-dihydrooxazole lithium (Li-( S )-2-FIDH), were prepared. Anionic homopolymerizations of achiral N -substituted maleimide (RMI) with the chiral initiators were investigated. The optically active polymers obtained were attributed to asymmetric induction of the chiral initiators. The very crowded chiral initiator Li-( S )-1-FIDH was found to play a better asymmetric induction role in the polymers than Li-( S )-2-FIDH. Anionic copolymerization of ( R )-(+)- N -1-phenylethyl maleimide and optically inactive RMI with Li-( S )-1-FIDH were also studied. © 2014 Society of Chemical Industry

Experimental and Modeling Investigation of n-Decane Pyrolysis at Supercritical Pressures

Zhenjian Jia,Hongyan Huang,Weixing Zhou,Fei Qi,Meirong Zeng

The pyrolysis mechanism of fuel under supercritical conditions is an important concern for developing regenerative cooling technology of advanced aircraft using hydrocarbon fuel as the primary coolant. n-Decane as a component of some jet fuels was studied at the temperature range from 773 to 943 K in a flow reactor under the pressure of 3, 4, and 5 MPa. Gas chromatograph/mass spectrometry was used to analyze the pyrolysis products, which were mainly alkanes from C1–C9 and alkenes from C2–C9. A kinetic model containing 164 species and 842 reactions has been developed and validated by the experimental results including the distributions of products and the chemical heat sink of fuel. The decomposition pathways of n-decane were illustrated through the reaction flux analysis. It is concluded that the C4–C9 alkanes are mainly generated by the recombinations of alkyls, while the small alkanes (C1–C3) are formed by H-abstraction reactions by C1–C3 alkyl radicals. The applicability at supercritical pressure and high fuel concentration condition of previous models was discussed, and the performance of the present model in reproducing the experimental data is reasonably good.

Self-powered photodetector based on a CsPbBr3/n-Si Schottky junction

Feng Hua,Xin Du,Zhenyu Huang,Yiting Gu,Jianfeng Wen,Fuchi Liu,Junxue Chen,Tao Tang

Self-powered photodetectors (SPPDs) are attracting considerable publicity due to their superiority over conventional photodetectors (PDs) in terms of high sensitivity, fast response, and no need for an external power supply. Halide perovskites are much anticipated in SPPDs for their unusual photoelectronic properties. This work developed a Schottky junction ${{\rm CsPbBr}_3}/{\rm n} \text{-} {\rm Si}$ SPPD by growing stable all-inorganic ${{\rm CsPbBr}_3}$ microcrystals on an n-Si substrate using a solution method. At zero bias, such Schottky SPPD has a very weak dark current (0.3 pA), a wide linear dynamic range (LDR, 110 dB), a sizeable on–off ratio (${\gt}{{10}^3}$), and high detectivity (${1.05} \times {{10}^{11}}\;{\rm Jones}$). Through the research of this project, it is expected to obtain a way to prepare Schottky photodiodes with high stability and self-driving capability.

Synthesis and bacterial inhibition of novel Ag2S–N–CQD composite material

Wang Kunjie,Liang Lei,Xu Jialin,Li Hongxia,Du Mei,Zhao Xiaoliang,Zhang Deyi,Feng Huixia,Fan Haiyan

The present work aims to combine carbon quantum dots (CQDs) with the good water solubility, biocompatibility, and low toxicity and nano-sized silver sulfide with excellent antibacterial effect in the synthesized composite. The composite was further treated with polyethyleneimine (PEI) and conjugated with graphene oxide (GO). The as-prepared composite Ag 2 S–CQDs–PEI–GO exhibits a core of Ag 2 S with the size of 20–50 nm and the shell of CQDs with the average particle size of 1.8 nm. The core shell structure is loaded on the template of PEI–GO. Strong antibacterial effect was observed on Ag 2 S–CQDs composite against four strands of bacteria Staphylococcus aureus ( S. aureus ), Escherichia coli ( E. coli ), Enterococcus faecalis ( E. faecalis ), and Pseudomonas aeruginosa ( P. aeruginosa ). We briefly discussed the bacteriostatic mechanism of the composite. The as-prepared composite has huge potential in the development of biomedicine.

Highly Sensitive Triethylamine Sensors Enabled by Co3O4/ZnO p-n Heterojunctions

Lin Wang,Haili Huang,Dongdong Zhang,Hung-Chun Wu,Meiling Li,Huilin Hou,Weiyou Yang,Xuhui Yu,Zonghua Wang

Triethylamine (TEA) is a typically volatile organic compound that poses significant environmental and health risks, due to its high toxicity and volatility. Currently, the exploration of TEA sensors based on semiconductor ZnO is still suffered by their intrinsically low sensitivity, slow response/recovery times, and poor selectivity. Herein, we develop the highly-sensitive TEA sensors based on rationally-designed Co 3 O 4 /ZnO p-n heterojunctions, in which the clustered Co 3 O 4 are incorporated into porous ZnO nanosheets. As a result, at the given operating temperature of 260 °C, the as-constructed sensors exhibit an overall enhanced performance with an excellent response of 140.5 to 100 ppm TEA, swift response/recovery times of 6/60 s and high selectivity, representing their promise toward practical applications in advanced TEA sensors.

Preparation of ZnNb2O6/N-doped carbon composites for lithium ion storage

Xuefeng Li,Jing Li,Rai Nauman Ali,Zhi Wang,Guojing Hu,Bin Xiang

Recently, conductive M-Nb-O composites have gained much attention as a novel lithium ion storage anode material. However, the conductivity and rate performance of M-Nb-O composites still need to be further enhanced. Herein, we have designed a facile strategy to prepare ZnNb 2 O 6 /N-doped carbon (ZnNb 2 O 6 /NC) which is derived from Nb 2 O 5 @zeolitic imidazole frameworks precursor. The ZnNb 2 O 6 /NC exhibits advanced energy storage properties including high initial capacity (673 mA h g −1 at 100 mA g −1 ), superior reversible specific capacity (412.6 mA h g −1 until 100 cycles at 100 mA g −1 ), long-term cyclic stability and excellent rate capability (470.5 mA h g −1 after 800 cycles at a relatively high current density of 2 A g −1 ).

Synthon Polymorphism and π–π Stacking in N-Phenyl-2-hydroxynicotinanilides

Yunping Zhoujin,Xing Yang,Mingtao Zhang,Ju Guo,Sean Parkin,Tonglei Li,Faquan Yu,Sihui Long

A lactam–lactam dimer (LLD) and lactam NH···O═C (amide) catemer (LAC) are two competing motifs in N-phenyl-2-hydroxynicotinanilides (PHNAs). Steric effects play an important role in determining the outcome of this competition, and in general, PHNAs with no or negligible steric hindrance take on a near-planar conformation and form LLDs, rather than the widely observed amide NH···O═C hydrogen-bond chains. Conversely, those with significant steric hindrance are forced to take on a twisted conformation and form a lactam NH···O═C (amide) hydrogen bond. Nevertheless, steric factors are not the only criteria, as an LLD and an LAC have been observed in the two polymorphs (1-I and 1-II) of 2-hydroxy-N-m-tolyl-nicotinamide (namely 2-oxo-1,2-dihydropyridine-3-carboxylic acid m-tolylamide, compound 1), although the molecules in both forms have a nearly identical conformation, in contrast to five other newly synthesized PHNAs (2–6), whose crystal structures are sustained on the LLD. Thus, synthon polymorphism is possible in conformationally planar PHNAs. Theoretical studies were performed to provide an explanation for this observation. The lattice energies of the two forms of 1 showed only an insignificant difference. A Hirshfeld analysis revealed that the loss of stability due to less hydrogen bonding in 1-II is compensated by the participation of π–π stacking. Other than the commonly observed LLD in the crystals, π–π stacking provides a significant stabilization for each crystal, with its particular effects being dependent on the substitution pattern of the compound. A noncovalent interaction (NCI) analysis further provided a visual demonstration of the important intermolecular interactions. Potentially the other planar compounds could behave in a similar manner.

Oxygen-enriched Fe-N-C electrocatalyst for efficient oxygen reduction reaction

Lang Wang,Yonghang Zhang,Linxiang Zhou,Guangtao Luo,Zhiwei Meng,Haodong Jin,Enze Zhu,Mingli Xu

The cathode's oxygen reduction reaction (ORR) plays a crucial role in a variety of fuel cells. Developing affordable and efficient non-precious electrocatalysts for the ORR poses a major hurdle in the realm of electrochemical energy technologies. This work presents a transition metal-based catalyst, Fe-ONC, in which Fe is loaded in an oxygen-enriched nitrogen-doped carbon (NC) material. Oxygen enrichment of the catalyst was achieved by a pre-oxidation strategy. The XPS analysis reveals that Fe-ONC exhibits a higher abundance of oxidized species. The Fe of Fe-ONC exists in the form of Fe 3 O 4 particles and Fe-N x , respectively, which are uniformly distributed in the NC. The even spread of iron sites and the plentiful presence of oxygen-rich species are key factors in the superior ORR efficiency of Fe-ONC. Fe-ONC's half-wave potential (E 1/2 ) in an alkaline environment (0.1 M KOH) stands at 0.891 V, markedly surpassing the standard commercial Pt/C value (0.840 V). Additionally, Fe-ONC demonstrated enhanced longevity and resistance to ethanol in comparison to commercially available Pt/C. Fe-ONC's outstanding efficacy highlights its potential as an alternative to precious metal catalysts. The document outlines a plan for creating ORR catalytic materials that are sustainable, economical, and efficient.

Co ions doping enhances n-butanol sensing performance of In2O3 nanospheres

Zhiguo Yang,Xingtai Chen,Qiuying Chen,Jiayi Qu,Yujun Guo,Kaiwen Zhou,Tianren Wang,Davoud Dastan,Xiaoning Wang,Feifei Wang,Xiaoming Tan,Xi-Tao Yin,Xiaoguang Ma

In this work, In 2 O 3 nanospheres were synthesized using urea as a carbon template and modified with Co ions. The synthesized materials were characterized using various instruments to obtain information about the elemental composition and morphology of the materials. The results showed that Co ions replaced the lattice position of In ions and synthesized nanospheres aggregated from 20 nm particles. The results of gas sensitivity tests on all the samples showed that the response to 50 ppm n-butanol at 250 °C reached 540 when Co was doped up to 5 at%. In comparison, the sensor showed very low response to benzene gas with good selectivity. The high response of the sensor to n-butanol is due to the increase in vacancy oxygen content and redox reactions due to the multivalent nature of Co ions. The article concludes with a detailed analysis of the sensing mechanism.

Silicene/poly(N-isopropylacrylamide) smart hydrogels as remote light-controlled switches

Tiantian Fang,Xifan Chen,Changyu Yang,Yaqi Cao,Junshi Zhang,WenChao Peng,Yang Li,Fengbao Zhang,Xiaobin Fan

Smart hydrogels with good flexibility and biocompatibility have been widely used. The common near-infrared (NIR) photothermal agents are facing a trade-off between good photothermal-conversion efficiency and high biocompatibility. Therefore, developing new metal-free photothermal agents with low cost, high biocompatibility and excellent phase stability is still in urgent need. In this study, we successfully combined poly( N -isopropylacrylamide) (PNIPAM) with the two-dimensional (2D) silicene nanosheets via the in situ polymerization method. Attributed to the thermal-responsive nature of PNIPAM and the excellent photothermal properties of 2D silicene, the obtained silicene/PNIPAM composite hydrogels exhibited dual thermal and NIR responsive properties. This smart hydrogel showed rapid, reversible and repeatable NIR light-responsive behaviors. The volume of this smart hydrogels can shrink significantly under NIR irradiation and recover to its original size without the NIR irradiation. Remote near-infrared light-controlled microfluidic pipelines and electronic switches based on obtained silicene/PNIPAM composite hydrogels were also demonstrated. This work significantly broadens the application prospects of silicene-based hydrogels in remote light-controlled devices.

Rapid Electrochemical Sensing of Zn(II) Using MesoporousMnO2@N-Graphene Composites

Xiangle Meng,Xiuxiu Dong,Dong Liu,Qijian Niu,Shun Lu,Tianyan You