Surfactants are widely used to stabilise emulsions across chemical, pharmaceutical, and environmental processes, yet conventional systems often lack controllability once formed. Smart surfactants capable of reversible emulsification and demulsification therefore offer a promising route toward adaptive formulations, especially when activated by non-invasive light stimuli. In this study, a morpholine-functionalised, photoswitchable azobenzene surfactant (MBAB) was synthesised to enable controllable reversible emulsion through trans-cis photoisomerisation. Using MBAB, a stable, reversible oil-in-water emulsion (MBAB/CTAB/n-hexane/water) was constructed, exhibiting repeatable demulsification and re-emulsification under alternating ultraviolet and visible light irradiation. Kinetically, the hydrophilicity of morpholine ring enhances interfacial hydration, resulting in robuster interfacial membrane and slower photoresponsive behaviour compared with linear alkyl analogues. Beyond demulsification and re-emulsification function, a reversible phase-transfer emulsion system (MBAB/noctanol/water) was also established, in which UV-induced trans-cis isomerisation increases MBAB's polarity, driving its migration from the n-octanol phase into water, with visible light restoring the original phase distribution. Both systems display excellent cycling stability, maintaining performance over at least ten switching cycles without significant loss of efficiency. Overall, this work provides an effective strategy for designing reversible photoresponsive surfactants and light-switchable emulsions, offering new opportunities for studying stimulus-responsive interfacial assembly and enabling intelligent separation and controlled-release technologies.

In this study, we investigated the friction mechanisms behind the observed changes in friction of niobium diselenide (NbSe2) thin films under varying normal bias voltages. The results show that both the friction force and coefficient of friction (COF) increase with the application of positive and negative bias voltages. These friction changes are significantly affected by the electrostatic force on the sample surface and the electronic excitation during friction leads to energy dissipation, ultimately increasing friction. These findings not only increase our understanding of the interfacial friction phenomenon of nano-electric friction, but also help to control energy dissipation of sliding nanofriction, making electronic control of friction possible.

Efficient separation of Xenon (Xe) and Krypton (Kr) is a significant process for their wide industrial applications and potential environmental concerns. Owing to the inert atomic gases (Xe and Kr) nature with similar physical and chemical properties, it is a great challenge to achieve efficient separation of the Xe/Kr mixture. Herein, we report a series of microporous lanthanide based metal-organic frameworks Ln (BTC) (H2O)& sdot;(DMF)1.1 (Ln-MOF) (Dy-BTC (1), Er-BTC (2), and Yb-BTC (3)) with ultrahigh thermal stability for adsorptive Xe/Kr separation. These three isostructural Ln-MOFs consisted of lanthanide metal ions and 1,3,5-benzene dicarboxylate ligands that possess a square channel with pore sizes of 6-7 angstrom. By substitution of Ln ions, Yb-BTC shows the smallest pore size among the three compounds which enables its obvious higher Xe/Kr selectivity compared with the other two LnMOFs. Yb-BTC exhibits a moderately high Xe uptake of 2.5 mmol/g (298 K and 1 bar), and a significantly high Xe/Kr uptake ratio of 3.8, indicative of its great potential for separation of Xe/Kr mixture. The effective Xe/Kr separation ability of Yb-BTC was also confirmed by a breakthrough experiment.

In this experiment, the novel color developing agent 4-nitroazobenzenesalicylidene fluorescence ketone was used as raw material to determine Sn(IV) by coordination fluorescence method. At the maximum excitation and emission wavelengths (λex/λem = 455 nm/552 nm), the Sn(IV) concentration in the range of 1.50–3.50 µg/mL showed a good linear relationship with the relative fluorescence intensity. The optimum experimental conditions and possible reaction mechanism were studied. The linear regression equation is ΔF = 83.4032–19.7658ρ(µg/mL), r = 0.9992. The detection limit was 0.0771 µg/mL and Ka = 3.66 × 104 M−1. After shielding the interfering ions, trace amounts of Sn(IV) were detected in synthetic water samples, laboratory wastewater, and canned asparagus. The recoveries were 101.64

Abstract In this experiment, a newly synthesized chromogenic agent o-vanillin fluorescence ketone was used to establish a method for the determination of Mn(II) by catalytic kinetic fluorescence. At the maximum excitation and emission wavelengths (λex/λem = 495 nm/578 nm) Mn(II) showed a negative correlation with fluorescence intensity in the range of 0.005 ~ 0.025 µg/mL and a good linear relationship between concentration and ΔF value. The optimal experimental conditions were investigated and the possible reaction mechanism was explored. The linear regression equation was ΔF = 937.7714 + 7287.7498ρ (µg/mL), r = 0.9993. The detection limit was 3.690×10− 3 µg/mL. The samples were analyzed after masking the interfering ions, and trace amounts of Mn(II) were detected in tap water, Yellow River water and tea leachate with the spiked recoveries of 99.05%, 100.0% and 103.32%, respectively. Satisfactory results were obtained.

In this experiment, the resonance Rayleigh scattering spectra of the Al(III)-chromium azure S-cetyltrimethyl ammonium bromide system were investigated. The optimal experimental conditions of the system were optimized, the interference of other ions to the system was investigated, and the reaction mechanism was discussed. The results show that: Aluminum(III) forms an anion with chromium azure S in a weakly acidic medium and then forms ionic association with cetyltrimethyl ammonium bromide under electrostatic and hydrophobic effects, which increases the resonance Rayleigh scattering intensity of the system. The mass concentration of Al(III) at 598.1 nm showed a good linear relationship with the resonance Rayleigh scattering intensity in the range of 0.02–0.16 μg/mL with the correlation coefficient of 0.9989 and the detection limit of 1.8 ng/mL. The relative standard deviation (RSDS, n = 6) was less than 1.1

Pt-based metals are very effective catalysts widely adopted in many fields. But the high cost prevents its further industrial application. One of the effective ways to solve the problem is to replace platinum with relatively cheap palladium and its alloy with copper. However, producing Pd/Cu bimetallic catalysts efficiently and economically with controllable particle size and uniform distribution is still challenging, especially when trying to reduce the consumption of precious metals. In this paper, ultrasmall palladium/copper (Pd/Cu) bimetallic catalysts with even dispersion were prepared on multi-walled carbon nanotubes (MWCNTs) by adding polyethylene glycol 400 (PEG 400) as a reducing agent and stabilizer under visible light irradiation at room temperature. The catalytic performance was studied in the catalysis of p-nitrophenol (p-NP) reduction. Of all the bimetallic catalysts produced in different conditions, the best one was obtained under the reaction condition of pH = 7 and violet light irradiation (wavelength 380-435 nm). The average particle size of 0.85 nm, and the apparent rate constant in the catalysis is 1.47 min-1. This research probes the role of visible light as a key kinetic controlling method in the formation of ultrasmall particles (UPs). It proves the effectiveness of using visible light irradiation as an effective and more "green chemistry" approach to get precious metal UPs as catalysts beyond the traditional ultraviolet or laser photochemistry methods.

The reaction of the N,N-diethyl-N'-(p-nitrobenzoyl)thiourea with K2[PtCl4] results in the complex of configurational cis-[Pt(L-kS,O)2], and structurally characterized by elemental analyses, FT-IR, 1H NMR, 13H NMR, UV–Vis spectroscopy, and cis-[Pt(L-kS,O)2] complex have been also characterized by a single-crystal X-ray diffraction study. The cis-[Pt(L-kS,O)2] crystallizes in the monoclinic crystal system, space group P21/c, with Z = 4, and unit cell parameters, a = 15.09299(15) Å, b = 15.26600(14) Å, c = 14.39268(14) Å, α = 90°, β = 107.6347(11)° and γ = 90°. The single-crystal diffraction analysis of the complex shows that the molecular configuration of cis-[Pt(L-kS,O)2] is a slightly distorted square-planar geometry, and both deprotonated ligands (L) contribute one O atom and one S atom coordinate with a central Pt(II) ion. The intermolecular interactions in the cis-[Pt(L-kS,O)2] complex were analyzed using the Hirshfeld surface method, including 2D fingerprint plots. In addition, the fluorescence properties of the compounds at room temperature were also studied. The results show that both ligands and complexes have good fluorescence properties, and the fluorescence intensity of the coordination compound enhances. In this paper, single-crystal X-ray analysis shows cis-[Pt(L-kS,O)2] belongs to monoclinic crystal system, space group P21/c. The connectivity of the ligand to the metal as 2:1 and the platinum atom is coordinated with two N,N-diethyl-N'-(p-nitrobenzoyl)thiourea ligands in a distorted square-planar geometry.

以可见光作为冷光源,多壁碳纳米管(MWCNTs)为载体,在聚乙二醇(PEG)的水溶液体系中用简单的一步法可控合成了超细铂铜纳米催化剂,并就其在对硝基苯酚(p-NP)还原反应中的催化活性进行了研究.透射电子显微镜(TEM)图显示该催化剂为分散均匀的球状超细铂铜纳米粒子,平均粒径为0.99 nm.X射线衍射(XRD)表征结果显示催化剂的衍射峰介于Pt(fcc)和Cu(fcc)标准衍射峰之间,这说明该催化剂中Pt与Cu以面心立方晶格(fcc)结构的合金形式存在.X射线光电子能谱(XPS)结果证明该催化剂主要以PtCu双金属的同质结构形式存在,但还有少量Pt11和CuⅡ氧化态物质,这与少量Pt0 和Cu0 纳米粒子的自催化氧化有关.研究表明,当Pt:Cu的摩尔比为1∶ 1,反应溶液的pH值为10时,在350～455 nm可见光的照射下合成的催化剂对p-NP的反应速率常数为0.92 min-1,是铂/多壁碳纳米管(Pt/MWCNTs)催化剂的2倍,且稳定性良好.可见光照加速了反应体系的水解速率,影响了水解产物的物种分布.同时,由于双金属催化剂中一定量Cu原子的引入压缩了原来的Pt晶格,这种晶格应变及双金属的协同作用影响了催化剂的选择性和活性.

Based on the H2SO4-Rhodamine B-KBrO3 system, the kinetic fluorescence method was used to determine formaldehyde. The experimental results show that in the sulfuric acid medium, the fading process of oxidized rhodamine B by potassium bromate is inhibited by the catalytic action of formaldehyde. The results showed that the formaldehyde concentration in the range of 0.4 to 4.4 μmol/L had a good linear relationship with lg (IF/I0F) = 0.01385 c (μmol/L) + 0.02353, the correlation coefficient was 0.9974, and the method detection limit was 0.3027 μmol/L. In the determination of formaldehyde in the synthetical water sample and laundry water, the recoveries were 98.68% and 103.20%. The results were consistent with the certified value.

铂金属催化剂是化学工业生产当中催化效率最高的贵金属催化剂之一,广泛用于析氧反应、析氢反应、甲醇氧化反应、氧还原反应、交叉偶联反应以及燃料电池等领域.文章对利用金属两相界面间的不同金属扩散速率差异所导致的柯肯达尔效应为理论基础的中空纳米笼结构铂族金属催化剂的形貌可控合成方法进行了综述.以近年来研究进展为依据,重点评述了利用柯肯达尔效应合成纳米尺度下的金属催化剂的反应机理以及柯肯达尔效应的逆过程形成笼结构的反应机理.最后对今后更进一步的合成方法研究进行了讨论.

The hydrolysis of K-2[PtCl4] under visible light, the equilibrium, morphology, and size of Pt NPs combined with CDs, the valence states of Pt element and the bonding of Pt NPs with CDs, the influence of different kinds of cyclodextrin (alpha, beta, gamma-CDs), the acidity of the solution, and the visible light color on the catalytic ability of Pt NPs were all researched by typical approaches. All results prove visible light irradiation is effectively playing a key role in the reaction process to form Pt NPs in a very narrow size distribution. pH = 9, beta-CDs, and purple visible light are the optimized reaction conditions. The Pt-CDs present a high rate constant of 0.88 min(-1)in the catalytic reduction of4-NP. This research is beneficial for expanding photochemical approaches from ultraviolet light to visible light, which is more of green chemistry, low cost, and facile.

Photochemistry to prepare platinum nanoparticles (Pt NPs) is an essential way to control Pt NPs catalyst size distribution. This article reports a series of morphologically controlled syntheses of Pt NPs loaded on modified carbon nanotube (Pt-CNTs). In the synthesis, Polyethylene glycol (PEG) participates in reactions both as a reducing agent and a stabilizer. Visible light irradiation was adopted as a kinetic controlling approach. Typical 4 -nitrophenol ( 4 -NP) reduction was adopted to probe the catalytic performances. Characterizations prove that visible light irradiation is an effective way to control the reaction process. In the optimized reaction conditions, i.e., when the ratio PEG:H 2 O is 1:9, and the pH is 10, the as-prepared Pt NPs are consequently in a very narrow sized distribution with an average diameter of 1.29 nm. The Pt-CNTs present a high reaction rate constant of 0.624 min -1 in the catalytic reduction of 4 -NP. All the research results are beneficial for exploring more green chemistry and facile photochemical approaches in the controlled preparation of Pt nanocatalysts.

Here, platinum nanoparticles were synthesized on multi-walled carbon nanotubes (MWCNTs) in one step under the irradiation of visible light without any extra additives except ethylene glycol (EG) as the reducing agent and stabilizer, and Pt/MWCNTs composites were successfully prepared. The catalytic performance of Pt/MWCNTs was studied in the reduction of p-nitrophenol (p-NP). The morphology and crystal structure of as-synthesized materi-als were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Visible light irradiation promotes the hydrolysis of a [PtCl4]2-precursor in EG aqueous solution. By the electronic effect of the metal interface, the reduc-tion of platinum precursors makes the formation of the uniformly dispersed Pt metal ultra-small particles with an average of 2.1 nm size. The as-prepared Pt/MWCNTs effectively catalyzed the reduction of p-NP to p-aminophenol (p-AP) with NaBH4, exhibiting a high catalytic performance with an apparent rate constant of 0.25 min-1. Further-more, high reusability without significant activity loss presents that Pt/MWCNTs prepared can be an excellent and stable catalyst. The experimental results prove that besides traditional light irradiation methods, e.g. ultraviolet, the proper utilization of visible light is also a very effective method for preparing platinum metal catalysts and the morphology control can be achieved in some simple ways rather than complex reaction conditions.

利用湿化学法的可见光动力学控制策略,在未添加表面活性剂的乙二醇水溶液体系中,以多壁碳纳米管(MWC-NTs)为载体,通过一步法合成了钯多晶纳米催化剂,其平均粒径为16.5 nm.并通过傅立叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、X射线衍射仪(XRD)和透射电子显微镜(TEM)完成了催化剂的微结构、组成和形貌的表征研究.结果表明,在可见光辅助下,乙二醇可以作为还原剂和稳定剂来制备纳米催化剂.由于金属的界面电子效应的影响,钯前驱体倾向于形成粒径比较大的多晶状颗粒.在对硝基苯酚(p-NP)的还原反应中,该催化剂的活化能为29.29 kJ/mol,室温下速率常数为0.2484 min-1,显示出了较高的催化活性.

A catalytic kinetic fluorescence method for the detection of trace bismuth(III) was developed, which focuses on the fading reaction of hydrogen peroxide that oxidizes eosin Y under the acidity of pH 4.50 and 90 degrees C. Experiments showed that bismuth could catalyze the oxidation of eosin Y by hydrogen peroxide; simultaneously, the fluorescence intensity was weakened or lost. The linear relationship between bismuth and eosin Y can be used to determine trace amounts of bismuth. The results showed that the concentration of bismuth in the range of 4.0 x 10(-4) to 4.0 x 10(-3) mu g/L showed a good linear relationship with lg(I-F(0)/I-F), the correlation coefficient was 0.9971, and the detection limit of the method was 1.9 x 10(-5) mu g/L. The method could be used for the determination of bismuth in human hair and water samples.

建立了以Co(Ⅱ)为催化剂,催化过氧化氢氧化桑色素使其荧光减弱的催化动力学荧光法.在pH 10.70的Na2B4O7·10H2O-NaOH缓冲溶液中,痕量钴(Ⅱ)离子对0.24％的H2O2溶液氧化4.0×10-7 mol/L的桑色素溶液有明显的催化作用.在最大吸收波长处(λex/λem=416.5nm/556.4nm),体系的荧光强度在一定范围内与Co(Ⅱ)的浓度呈线性相关,线性范围为0.8～8.0 μg/L,检出限为0.14μg/L.考察了体系的共存离子干扰情况,对灰钙土和分子筛样品进行了分析检测,回收率分别为95.0％～ 110.0％和98.9％ ～101.9％.

This paper presents the visible light-assisted synthesis of surfactant-free Pt nanoparticles (Pt-NPs) supported on multi-walled carbon nanotubes (MWCNTs) at ambient condition. Transmission electron microscopy (TEM) images indicate that Pt-NPs with high density and relative small in size (about 2 nm) were monodispersed on the surface of MWCNTs. The characterizations of Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD) and ultraviolet–visible spectroscopy (UV–Vis) prove that visible light irradiation significantly affect the species distribution of [PtCl4]2− precursor in the hydrolysis and then promote hydrolysate Pt oxides loading on MWCNTs. The loading process decides the morphology of Pt-NPs rather than the following precursor reduction, which does not change the morphology but only the valance state of platinum. The catalytic activity of Pt/MWCNTs was tested in subsequent methanol electrochemical reactions and 4-nitrophenol (4-NP) reduction.

: Basedonthecatalytic effects of Cu(II) onKIO 4 oxidizedsafranineT, anewsystemfor determining tracing copper with catalytic kinetic fluorescence method is established.After adding Cu(II), the fluorescence intensity at 580 nm is significantly reduced. Within the concentration range of 2.50 － 32.50 ng ∙ mL － 1 , a linear relationship between the concentration of Cu(II) and lg( F 0 / F ) in the system is observed. Based on this new experiment, the design and implementation of instrumental analysis laboratory is investigated. Meanwhile, in order to achieve high quality of the inquiry experiment teaching, teachers should be responsible for proposition and feasibility.

Aluminum is a class of important metal material that has been widely used in many fields in industrial production.More and more aluminum compounds are discharged into water system along with the wastewater.Therefore, it is very necessary to determine the content of aluminum in water.The resonance Rayleigh scattering spectrum of aluminum(Ⅲ)-aluminon-cetyltrimethylammonium bromide system was investigated.The determination conditions were optimized.The interference of other ions in system was investigated.The reaction mechanism was preliminarily discussed.The determination method of aluminum by resonance Rayleigh scattering was finally established.The results indicated that aluminum could form complex anion with aluminon (aurin tricarboxylic acid, ATA) in weakly acid medium.Then the ion association complex was formed between complex anion and cetyltrimethylammonium bromide (CTMAB) via electrostatic attraction and hydrophobic interaction, leading to the increase of resonance Rayleigh scattering intensity of system.The mass concentration of Al(Ⅲ) in range of 0.02-0.16 μg/mL showed good linearity to the corresponding resonance Rayleigh scattering intensity at 598.1 nm with correlation coefficient of 0.998 9.The detection limit was 1.8 ng/mL.The proposed method was applied for the analysis of actual water sample.The relative standard deviation (RSD, n=6) was not more than 1.1%.The recoveries were between 93.5% and 100.8%.The determination results were consistent with those obtained by atomic absorption spectrometry (AAS).