Surfactant-free oil/water and bicontinuous microemulsion composed of benzene,ethanol and water

Generally,a microemulsion consists of oil,water,surfactant and sometimes cosurfactant.Herein,we report a novel suffactant-free microemulsion（denoted as SFME） composed of benzene,water and ethanol without the amphiphilic molecular structure of traditional surfactant.The phase behavior of the ternary system was investigated,finding that there were a single-phase region and a two-phase region in ternary phase diagram.The electrical conductivity measurement was employed to investigate the microregion of the single-phase region,and a bicontinuous microregion and a benzene-in-water（O/W） microemulsion microregion were identified,which was confirmed by freeze-fracture transmission electron microscopy（FF-TEM） observations.The sizes of the microemulsion droplets are in the range of 20-50 nm.

Preparation and Characterization of Polyaniline Nanofibers by Template-free Method

In the presence of p-toluene sulfonic acid (TSA) as a dopant, polyaniline (PAni) nanofibers, (about 80^-65 nm in diameter) were successfully synthesized with a chemical template-free method. It was found that the formation probability, morphology, and diameter of the resulting PAni-TSA nanofibers were sensitive to the synthetic conditions, such as reaction temperature, the molar ratio of TSA to aniline, and the concentration of TSA in the polymerization media. The molecular structure was characterized by using the FT-IR, Raman spectra and X-ray diffraction, which shows that the main chain structure of PAni-TSA nanofibers was in agreement with that of granular PAni.

Organotemplate-free Hydrothermal Synthesis of SUZ-4 Zeolite: Influence of Synthesis Conditions

Various conditions were investigated in detail for the novel organic template-free static hydrothermal synthesis of SUZ-4 zeolite in the presence of seeds. The obtained samples were characterized by XRD （X-ray diffraction）, SEM （scanning electron microscope）, TG （thermal gravimetric analysis）, ICP （inductively coupling plasma） elemental analysis, nitrogen sorption isotherm and surface area. The results show that pure SUZ-4 zeolites with high crystallinity are obtained in a broad window of synthesis conditions： seed mass concentration 0.2%-2%, SIO2/A1203 molar ratio 21 25, KOH/SiO2 molar ratio 0.33 0.43, H20/SiO2 molar ratio 7.14-38.1, aging time 24 h, crystallization temperature 160℃, and crystallization time 6-10 d. Also, crystallinity and size of the rod-like SUZ-4 zeolite crystals are found to alter with the conditions.

Template-free hydrothermal synthesis and gas-sensitivity of hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres

Hollow-structured Cu_(0.3)Co_(2.7)O_(4) microspheres have been synthesized by a simple one-pot template-free hydrothermal method with copper sulfate,cobalt acetate and ammonia as raw materials.The products were characterized by powder X-ray diffraction,energy dispersive X-ray analysis,selected area electron diffraction,high-resolution transmission electron microscopy,scanning electron microscopy and BET measurements.The research results show that the hollow Cu_(0.3)Co_(2.7)O_(4) microspheres consist of single-crystalline nanocubes with the diameter of about 20 nm.The formation mechanism of hollow Cu_(0.3)Co_(2.7)O_(4) microspheres is suggested as Ostwald ripening in a solid-solution-solid process,and Cu_(0.3)Co_(2.7)O_(4) microspheres are mesoporous containing two pore sizes of 3.3 and 5.9 nm.The as-prepared Cu_(0.3)Co_(2.7)O_(4) sensors have optimal gas responses to 50×10^(−6) mg/m^(3) C_(2)H_(5)OH at 190℃.

Template-free Synthesis of a Novel 3D Cage-like Nanostructured α-Fe_2O_3

Synthesis of inorganic nanostructures with specific size and well defined morphologies has attracted considerable attention due to their superior electrical, optical, magnetic, and chemical properties. Up to now, various kinds of metal oxide, sulfide, and hydrate with controlled hierarchical and complex morphologies have been successfully synthesized.

Template-Free Bipotentiostatic Deposition of Thermoelectric BixTey Nano Arrays

Monodispersed Bi-Tenano arrays are achieved via template-free bipotentiostatic deposition. The diameter and length of individual nanorod is ~80 nm and ~250 nm respectively. The electrodeposition process is demonstrated to follow a two-step mechanism: an instantaneous reductive potential is applied to form dispersive nuclei, then a reverse oxidative potential strips partial Bi atoms to prevent further cross-growth. Repeatedly, the nano arrays film is obtained eventually. The thermoelectric properties of the obtained Bi-Tenano arrays such as electrical resistance, carrier density, Seebeck coefficient and power factor are measured to be 2.438 × 10-4?Ω·m, 4.251 × 1020 cm-3, -25.892 μV·K-1, 2.750 × 10-6 W·m-1·K2, respectively.

Design of Cadmium Hydroxyapatite Hierarchical Structures with Adjustable Morphology by a Template-free Hydrothermal Route

Cadmium hydroxyapatite（Cd-Hap） hierarchical structures with novel morphologies were successfully synthesized via a simple template-free and mild hydrothermal method. By properly monitoring the initial pH value of the reaction solutions, the morphology of the Cd-Hap crystals could be tuned to be bunch-like（consist of nanosized cuboids）, quasi peanut-like（consist of nanoparticles） and flower-like（consist of assembled bundles units）. On the basis of a series of contrast experiments over time, the probable growth mechanism and fabrication process of the products were proposed. The optical and photocatalytic properties of the obtained Cd-Hap hierarchical structures were firstly investigated. The results showed that pure Cd-Hap could only absorb UV light with wavelength shorter than -350 nm while hydroxyapatite supported Ag3PO4 composites showed a pronounced photocatalytic activity upon decomposition of methyl orange dye in aqueous solution under visible light irradiation. The support of hydroxyapatite can also greatly reduce the cost of expensive Ag3PO4 photocatalysts in practical applications.

Template-Free Hydrothermal Synthesis of β-FeOOH Nanorods and Their Catalytic Activity in the Degradation of Methyl Orange by a Photo-Fenton-Like Process

The rod-shaped form of crystalline β-FeOOH (akaganeite) was prepared by the template-free hydrothermal method with urea as the homogeneous precipitant. X-ray diffraction, field-emission scanning electron microscope and Fourier transform infrared spectrum were used to characterize the resulting products. The degradation of methyl orange (MO) was studied using the prepared nanostructure materials in a photo-Fenton-like process. MO degradation was effectively achieved by hydroxyl radicals that were generated in the heterogeneous catalysis process. Specific surface area of the prepared β-FeOOH was an important factor affecting the efficiency of MO degradation, which depended on the synthesis conditions such as the reaction temperature, the initial concentration of urea and FeCl3.6H2O as well as the n(urea)/n(Fe3+) ratio. The photodegradation efficiencies slightly decreased with the increase of initial pH in the range of 4.5 - 9.5, which indicated the prepared β-FeOOH catalyst can well overcome the drawback of a narrow pH range of homogeneous Fenton reaction. β-FeOOH catalysts loading and H2O2 concentration also play important effect on the degradation efficiency of MO. The prepared β-FeOOH showed good ability of reuse for multiple trials.

Template-Free Synthesis of Aligned Polyaniline Nanorods/Tubes and Copper/Copper Hydroxide Nanowires for Application as Fillers in Polymer Nanocomposites

Aligned polyaniline nanorods were synthesized in the presence of salicylic acid. Nanorods and nanotubes were also formed in the presence of camphorsulfonic acid (CSA) and para-toluenesulfonic acid (pTSA). Electrical conductivity measurements showed that the aligned nanorods had better electrical conductivity than the non-aligned nanostructures. Nanospheres were also observed in some cases. The formation of elongated nanostructures or spheres depended on the aniline monomer to surfactant molar ratio. This method in which nanostructures are formed using soft templates is often referred to as the template-free approach. Our success motivated us to explore the feasibility of obtaining similar metallic nanostructures without the use of a template. We successfully synthesized copper and copper hydroxide nanowires. While the copper nanowires formed as a mesh, the copper hydroxide nanowires formed as winding bundles. Upon switching the order in which the reactants were added, copper hydroxide nanoribbons were formed instead of bundles. Characterization of these nanostructures was done using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and the Four-point probe to measure electrical conductivity. Both metallic and organic nanowires that are fabricated by template-free methods are potential candidates for use as fillers in polymer nanocomposites. Polymer nanocomposites are found to be used in many advanced modern applications such as thermal interface materials in electronic devices which continue to be miniaturized, aerospace engineering where lightweight and robustness are important, sensors, medicine and catalytic activity.

Facile synthesis of hierarchical NaX zeolite from natural kaolinite for efficient Knoevenagel condensation

Zeolite catalysts have found extensive applications in the synthesis of various fine chemicals.However,the micropores of zeolites impose diffusion limitations on bulky molecules,greatly reducing the catalytic efficiency.Herein,we explore an economic and environmentally friendly method for synthesizing hierarchical NaX zeolite that exhibits improved catalytic performance in the Knoevenagel condensation reaction for producing the useful fine chemical 2-cyano-3-phenylacrylate.The synthesis was achieved via a low-temperature activation of kaolinite and subsequent in-situ transformation strategy without any template or seed.Systematic characterizations reveal that the synthesized NaX zeolite has both intercrystalline and intra-crystalline mesopores,smaller crystal size,and larger external specific surface area compared to commercial NaX zeolite.Detailed mechanism investigations show that the inter-crystalline mesopores are generated by stacking smaller crystals formed from in-situ crystallization of the depolymerized kaolinite,and the intra-crystalline mesopores are inherited from the pores in the depolymerized kaolinite.This synthesis strategy provides an energy-saving and effective way to construct hierarchical zeolites,which may gain wide applications in fine chemical manufacturing.

Coupling WO_(3-x) dots-encapsulated metal-organic frameworks and template-free branched polymerization for dual signal-amplified electrochemiluminescence biosensing

Developing accurate and sensitive DNA methyltransferase(MTase) analysis methods is essential for early clinical diagnosis and development of antimicrobial drug targets. In this work, by coupling WO_(3-x) dotsencapsulated metal-organic frameworks(MOFs) as co-reactants and terminal deoxynucleotidyl transferase(Td T)-mediated template-free branched polymerization, a dual signal-amplified electrochemiluminescent(ECL) biosensor was constructed to detect DNA adenine methylation(Dam) MTase. The employment of WO_(3-x) dots-encapsulated MOFs(i.e., NH_(2)-UIO66@WO_(3-x) ) was not only beneficial for biomolecule conjugation because of the abundant amino groups but also led to a 7-fold enhanced ECL response due to the increased loading of WO_(3-x). Moreover, Td T-mediated template-free branched polymerization promoted the capture of ECL emitters on the electrode surface, achieving 20-fold enhanced signal amplification. The presented ECL biosensor demonstrated a low detection limit of 2.4 × 10^(-4)U/m L, and displayed high reliability for the detection of Dam MTase in both spiked human serum and E. coli cell samples, and for the screening of potential inhibitors. This study opens a new avenue for designing a dual signal amplificationbased ECL bioassay for Dam MTase and screening inhibitors in the fields of clinical diagnosis and drug development.

Template-free synthesis of hollow carbon-based nanostructures from MOFs for rechargeable battery applications

Hollow carbon-based nanostructures(HCNs)have found broad applications in various fields,particularly rechargeable batteries.However,the syntheses of HCNs usually rely on template methods,which are time-consuming,low-yield,and environmentally detrimental.Metal-organic frameworks(MOFs),constructed by organic ligands and inorganic metal nodes,have been identified as effective platforms for preparing HCNs without adding extra templates.This review summarized the recent progress in template-free synthesis of HCNs enabled by MOFs and their applications in rechargeable batteries.Different template-free strategies were introduced first with mechanistic insights into the hollowing mechanism.Then the electrochemical performances of the HCNs were discussed with highlight on the structure-function correlation.It is found that the built-in cavities and nonporous for HCNs is of critical importance to increase the storage sites for high capacity,to enhance charge and mass transport kinetics for high-rate capability,and to ensure the resilient electrode structure for stable cycling.Finally,the challenges and opportunities regarding MOFs-derived HCNs and their applications in rechargeable batteries were discussed.

Fabrication of 3D hollow acorn-shell-like PtBi intermetallics via a surfactant-free pathway for efficient ethylene glycol electrooxidation

The synthesis of atomically ordered Pt-based intermetallic electrocatalysts for the direct alcohol fuel cells generally requires the addition of surfactants or the high-temperature annealing.However,some residual surfactants on the surface of the assynthesized catalysts would prevent the exposure of catalytic active sites,the high-temperature annealing process is easy to accelerate the sintering of the metal,which both lead to the decline of electrocatalytic performance.Herein,we construct the atomically ordered bimetallic PtBi intermetallics with clean surfaces and unique three-dimensional hollow acorn-shell-like structure(3D PtBi HASL)by a simple,low-temperature,surfactant-free one-pot synthetic approach.Benefiting from the special hollow structures,the obtained 3D PtBi HASL intermetallics expose abundant accessible active sites.Moreover,the introduction of oxophilic metal Bi can enhance adsorption of OHads,thereby significantly facilitating removal of poisoned intermediates.Density functional theory(DFT)simulations further indicate that formation of the PtBi intermetallic phase with the downshift of the Pt d-band center endows 3D Pt49.4Bi50.6 HASL intermetallics with significantly attenuated COads and enhanced OHads adsorption,bringing about the boosting electrocatalytic property.The mass activity of the 3D Pt49.4Bi50.6 HASL intermetallics for ethylene glycol oxidation reaction is as high as 24.67 A·mgPt^(−1),which is 12.98 times higher than that of commercial Pt/C(1.90 A·mgPt^(−1)).This work may inspire the design of Pt-based intermetallics as high-efficiency anode electrocatalysts for fuel cell applications.

Scalable nanomanufacturing of surfactant-free carbon nanotube inks for spray coatings with high conductivity

Spray-coated carbon nanotube films offer a simple and printable solution for fabricating low cost, lightweight, and flexible thin-film electronics. However, current nanotube spray inks require either a disruptive surfactant or destructive surface functionalization to stabilize dispersions at the cost of the electrical properties of the deposited film. We demonstrate that high-purity few-walled carbon nanotubes may be stabilized in isopropanol after surface functionalization and that optimizing the ink stability dramatically enhances the conductivity of subsequent spray-coated thin films. We consequently report a surfactant-free carbon nanotube ink for spray-coated thin films with conductivities reaching 2,100 S/cm. Zeta-potential measurements, used to quantify the nanotube ink dispersion quality, directly demonstrate a positive correlation with the spray- coated film conductivity, which is the key metric for high-performance printed electronics.

Two dimensional nanocarbons from biomass and biological molecules:Synthetic strategies and energy related applications

Two-dimensional(2D)carbon materials with ultrathin thickness,large lateral size,large surface area,accessible active sites and unique physical-chemical properties have been proven to be attractive electrode materials or catalysts for high-efficient energy storage and conversion materials.However,the conventional synthesis method for 2D carbon materials heavily depends on fossil-based feedstocks and goes through harsh conditions(e.g.,chemical vapor deposition),which are unsustainable and costly.Besides,the top-down method needs to use massive strong acids/oxidants,which is environmentallyunfriendly.Therefore,it is necessary to commit to seek green,sustainable and cost-effective approach for the synthesis of 2D carbon materials.As of now,biomass or biological molecules as carbon-rich resources have been viewed as a promising candidate for the 2D carbon material preparation owing to its abundance,renewability,nontoxicity and low-cost.Especially for nucleobases,as an emerging molecule have been shown great advantages for the construction of 2D materials guided by its multiple hydrogen-bonding interaction.Recently,our group have proposed a rather innovative strategy to produce 2D carbon materials by carbonization of nucleobases which has relatively high electrode potentials.These nucleobases can form planar network structure through hydrogen bonding interaction.Such hydrogenbonding can be stable at relatively high temperature,which confines C-C or C-N polymerization in a 2D plane.As a result,direct carbonization of nucleobases enables the formation of 2D carbon with highly sp2-conjugated and feature of heteroatom doping.This review systematically summarizes the recent development of the strategies to synthesize 2D sustainable carbon materials from biomass and biological molecules.The corresponding electrochemical applications such as lithium ion batteries,supercapacitors and fuel cell are selectively presented.At the end,the summary and future perspectives in this important field are provided to inspire further exploration.

Tunable gold nanostar synthesis with surfactant-free system

Gold nanoparticle is an important photothermal conversion material in photothermal imaging and photothermal therapy research.There are diverse gold nanoparticles,including gold nanospheres,gold nanorods,gold nanocages,gold nanoshells and gold nanostars.Among them,gold nanostar(AuNS)possesses more excellent prospective imaging contrast agent for cancer diagnosis than other shapes of gold nanoparticles because of its larger photon interception area and cross section as well as scattering characteristics.The properties of AuNS are susceptible to synthetic methods and conditions.In this study,we presented surfactant-free methods to synthesize AuNS,discussed the relationship of AuNS characterization with the synthetic conditions and tested its photothermal effect.The results indicated that length and number of branches in AuNSs were the main factor for absorption wavelength in photothermal conversion,and the Au NSs could be more precisely controlled by changing the synthesis conditions.

Preparation and characterization of hollow carambola-shaped silver sulfide microspheres using a microwave-assisted template-free method

A simple and convenient method, free of template, has been proposed to synthesize hollow carambolashaped Ag2 S microspheres with Ag NO3, thiourea（TU）, Na Cl and diethanolamine as reagents using a microwave-assisted method, at low temperatures of below 100 ℃. Powder X-ray diffraction（XRD）,scanning electron microscopy（FESEM） and high resolution transmission electron microscopy（HRTEM）were employed to characterize the morphology and composition of those microspheres. The results indicated that the hollow carambola-shaped silver sulfide microspheres（with high purity and homogeneous morphology） were prepared by an Ostwald ripening process. A possible formation mechanism of hollow carambola-shaped Ag2 S microspheres was proposed.

Environmentally benign synthesis of crystalline nanosized molecular sieves

Zeolites and zeo-type materials with nanosized dimensions are of great practical interest owing to their favorable transport properties,faster adsorption kinetics,and large external surface area.This mini-review presents recent developments in the organic template-free synthesis of nanosized zeolites and related materials.The advantages and challenges of these methods are addressed with particular attention to the green synthesis of nanozeolites.

Template-free synthesis and characterization of K-phillipsite for use in potassium extraction from seawater

Kbphillipsite was prepared using a hydrothermal method. Soluble glass and sodium aluminate were used as raw materials in the absence of an organic template. Investigations regarding the K＋ ions were con- ducted at room temperature to determine the ion-exchange capacity in the seawater sample and the selectivity coefficient of the mixed K＋-Na~ solution. The sample was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and energy dispersion spectroscopy （EDS）. The K＋ ion- exchange capacity is 51 mg/g in seawater and the selectivity coefficient is 75.1 in the mixed K＋-Na＋ solution. The sample has a selectivity preference for K＋, and therefore can be used to selectively extract potassium from seawater. The sample composed of Si, Al, K, Na, and O exhibits a cross-like shape and is a typical K-phillipsite structure.

Synthesis of ZSM-5 zeolite membranes without organic templates using a varying-concentration technique

Template-free nanosized ZSM-5 seeds with an average size of 15 nm were prepared from a synthesis solution with the composition 12Na2O∶100SiO2∶2Al2O3∶2500H2O. By the use of these seeds, thin ZSM-5 zeolite membranes were prepared on the outer surface of a porous α-alumina tube with a pore size of 2 μm in a gel system by varying-concentration synthesis with organic-free template. The first composition synthesis sol-gel was the same as seeds of molar composition and the second one was 12Na2O∶100SiO2∶2Al2O3∶5000H2O at 180 ℃ for 10 h, respectively. XRD shows that the film consists of well-crystallized ZSM-5 zeolite. SEM investigation indicats that the zeolite films on the supports are defect free and the film thickness is approximately 8 μm. The permeances for H2, N2, CH4 and CO2 are 8.94×10-7, 3.27×10-7, 3.9×10-7, 3.14×10-7 and 0.874×10-7 mol·m2·s-1·Pa-1, respectively. The ideal selectivity of membrane at room temperature for H2/CO2, H2/N2, H2/CH4 are 2.84, 2.73 and 2.29, respectively.