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Recently the urea and urinated wastewater electrolysis process has shown promising technology for hydrogen fuel green production in addition to denitrification of wastewater. However, to make the process economically valuable, the electrocatalysts nanoarchitecture, nanometer size, shape, facets, and composition need to be engineered to boost the urea oxidation reaction (UOR). This work demonstrates a simple and novel approach to the synthesis of mesoporous nickel phosphate nanoparticles (meso-NiPO) via chemical deposition from a surfactant liquid crystal template. Typically, the nickel ions dissolved in the aqueous domain of the hexagonal liquid crystalline phase of the Brij®78 template were chemically reacted with the sodium phosphate solution to precipitate the mesoporous nickel phosphate nanoarchitecture after washing up the surfactant. The physicochemical characterizations show the meso-NiPO exhibits an amorphous highly mesoporous structure with a higher specific surface area (43.50 m2/g) compared to the bare nickel phosphate (bare-NiPO, 4.26 m2/g) prepared in the absence of surfactant. The electrochemical performance of meso-NiPO electrocatalyst for the urea oxidation reaction in alkaline solution exhibits superior activity including a lower oxidation onset potential (0.30 V vs. Ag/AgCl), charge transfer resistance (3.35 O) and mass activity of 700.7 mA/cm2 mg at the oxidation potential of 0.6 V vs. Ag/AgCl. Moreover, the meso-NiPO reveals long-term stability, and 97.5% of the steady-state oxidation current was maintained after the 3-hour urea electrolysis test. Using an H-shape urea electrolyzer, the corresponding cathodic hydrogen production rate reached 415 µmol/h and a Faradic efficiency of 96.8 % at an applied bias of 2.0 V. The electroactivity high performance of the mesoporous nickel phosphate is ascribed to the high specific surface area and mesoporous architecture that provide efficient charge transfer, as well as mass transport of the electroactive species. The chemical deposition from a surfactant liquid crystal template has the advantages of a one-pot template, applicable to the synthesis of a wide range of nanomaterials with various compositions and nanoarchitectures at room temperature for application in electrochemical energy production and storage systems.

This work reports the synthesis of nickel/nickel hydroxides nanoflakes (Ni/Ni(OH)2-NFs) at room temperature via a novel chemical deposition and exfoliation from a liquid crystal template mixture. The nickel ions dissolved in the interstitial aqueous domain of the Brij®78 hexagonal liquid crystal template were deposited by a reducing agent of sodium borohydride that concurrently reduces the nickel ions and generates extreme hydrogen gas bubbles, that exfoliated the nickel/nickel hydroxide layers. The Ni/Ni(OH)2-NFs crystal structure, morphology, and surface area characterizations revealed the formation of semi-crystalline α-Ni(OH)2 nanoflakes with a thickness of approximately 10 nm and a specific surface area of about 135 m2/g. The electrochemical measurements of cyclic voltammetry, chronoamperometry, and impedance analysis showed that the Ni/Ni(OH)2-NFs exhibited significant performance for the glucose non-enzymatic oxidation in an alkaline solution in comparison to the bare-nickel hydroxide (bare-Ni(OH)2) deposited without surfactant. The Ni/Ni(OH)2-NFs electrode showed superior glucose oxidation activity over the bare-Ni(OH)2 catalyst with a sensitivity of 1.078 mA mM−1 cm−2 with a linear concentration dependency range from 0.2 to 60 mM and a detection limit of 0.2 mM (S/N = 3). The enhanced electrochemical active surface area and mesoporosity of the 2D nanoflakes make the Ni/Ni(OH)2-NFs a promising catalyst in the application of glucose non-enzymatic sensing.

Pure tetragonal zirconia nanopowder was prepared via lamellar liquid crystal method combined with a thermal sulfated zirconyl chloride hydrosol. The lamellar liquid crystal region in the sodium dodecyl sulfate/1-decanol/water ternary phase diagram was observed by polarizing optical micrographic images. The impact of the molar ratio R s = [ Z r 4 + ] [ S O 4 2 − ] on the phase and morphology of zirconia was investigated. Results showed that the molar ratio Rs affected the phase structure and morphological characteristic of zirconia particles. Moreover, the morphology was transformed from almost peanut particles to spherical ones, whereas tetragonal phases changed into monoclinic phase with the increase in Rs. [ABSTRACT FROM AUTHOR]

The surface composite and morphology of binary metal sulfides are the key for efficient overall water splitting. However, tuning the morphology and surface composition of binary metal sulfides in a facile way is still a challenge. Herein, binary Fe-Ni sulfides supported on nickel foam (FeNi-S/NF) with different morphology and composition ratio of Fe/Ni have been synthesized through a facile one-step electrodeposition assisted by liquid crystal template (LCT). The binary FeNi-S has improved activity and conductivity compared to single metal sulfides. LCT-assisted porous FeNi-S film composed of uniform nanospheres is obviously different from planar film electrodeposited in water solution. LCT-assisted FeNi-S nanospheres are covered by many interwoven nanosheets, implying more exposed active sites for water splitting. Furthermore, the different Fe/Ni ratios of FeNi-S/NF samples have been systematically studied to explore the influence of Fe-incorporation on intrinsic activity of FeNi-S/NF. And the sample with Fe/Ni ratio (3/1) demonstrates the best activity and excellent stability for overall water electrolysis. Therefore, our work provides a facile and controllable access to binary metal sulfides with excellent performances for overall water splitting. [ABSTRACT FROM AUTHOR]

Recently the urea and urinated wastewater electrolysis process has shown promising technology for hydrogen fuel green production in addition to denitrification of wastewater. However, to make the process economically valuable, the electrocatalysts nanoarchitecture, nanometer size, shape, facets, and composition need to be engineered to boost the urea oxidation reaction (UOR). This work demonstrates a simple and novel approach to the synthesis of mesoporous nickel phosphate nanoparticles (meso -NiPO) via chemical deposition from a surfactant liquid crystal template. Typically, the nickel ions dissolved in the aqueous domain of the hexagonal liquid crystalline phase of the Brij®78 template were chemically reacted with the sodium phosphate solution to precipitate the mesoporous nickel phosphate nanoarchitecture after washing up the surfactant. The physicochemical characterizations show the meso -NiPO exhibits an amorphous highly mesoporous structure with a higher specific surface area (43.50 m2/g) compared to the bare nickel phosphate (bare -NiPO, 4.26 m2/g) prepared in the absence of surfactant. The electrochemical performance of meso -NiPO electrocatalyst for the urea oxidation reaction in alkaline solution exhibits superior activity including a lower oxidation onset potential (0.30 V vs. Ag/AgCl), charge transfer resistance (3.35 O) and mass activity of 700.7 mA/cm2 mg at the oxidation potential of 0.6 V vs. Ag/AgCl. Moreover, the meso -NiPO reveals long-term stability, and 97.5% of the steady-state oxidation current was maintained after the 3-hour urea electrolysis test. Using an H-shape urea electrolyzer, the corresponding cathodic hydrogen production rate reached 415 µmol/h and a Faradic efficiency of 96.8 % at an applied bias of 2.0 V. The electroactivity high performance of the mesoporous nickel phosphate is ascribed to the high specific surface area and mesoporous architecture that provide efficient charge transfer, as well as mass transport of the electroactive species. The chemical deposition from a surfactant liquid crystal template has the advantages of a one-pot template, applicable to the synthesis of a wide range of nanomaterials with various compositions and nanoarchitectures at room temperature for application in electrochemical energy production and storage systems. [ABSTRACT FROM AUTHOR]

MoS x as a promising electrocatalyst for hydrogen evolution reaction (HER) has the active sites of rims and edges and inert sites of basal plane. A strategy to activate MoS x is to produce more unsaturated S or S vacancies on the inert plane by designing unique nanostructure. Herein, we report a facile electrodeposition assisted by liquid crystal template (LCT) to prepare MoS x film on ITO substrate (MoS x (LCT)). XPS confirms the state of Mo and S of the obtained MoS x film. SEM shows that there are many uniform disk bulges with the diameter of about 100 nm on the surface of MoS x (LCT), which may provide more rims and edges of MoS x . While the electrodeposited MoS x film in water (MoS x (H 2 O)) is a smooth plane structure. The electrochemical measurements show MoS x (LCT) exhibits an ultrahigh activity for HER with the small onsetpotential very close to that of Pt/C, which may be due to not only the uniform disk bulges but also the more unsaturated S atoms of MoS x (LCT). The electrodeposition assisted by LCT may be a novel strategy to prepare novel nanostructure and activate MoS x -based electrocatalysts for HER. [ABSTRACT FROM AUTHOR]

Nickel hydroxide nanoflakes (Ni(OH)-NF) were prepared by chemical deposition and in situ exfoliation of nickel hydroxide layers confined in the aqueous domain of the liquid crystalline hexagonal template of Brij®78 surfactant. Using excess of sodium borohydride as a reducing agent generates concurrent excessive dynamic hydrogen bubbles which exfoliated and fragmented the nickel hydroxide layers precipitated within the soft hexagonal template. The physicochemical characterizations of Ni(OH)-NF by using surface area analyser, X-ray diffraction (XRD), XPS and transmission electron microscope (TEM) showed the formation of α-Ni(OH) nanoflakes with thickness of 2-3 nm and have about 450 m g surface area which is 20 times higher than that for bare nickel (bare-Ni) deposited without surfactant template. The electrocatalytic activity of the Ni(OH)-NF catalyst for urea electrolysis was studied by cyclic voltammetry and chronoamperometry techniques. The Ni(OH)-NF has shown a superior activity for the electrochemical oxidation of urea in alkaline solution and exhibits more than tenfold increase in activity in comparison with the bare-Ni deposit. The enhancement of urea electrooxidation activity was related to the superficial enhancement in the electroactive surface area of Ni(OH)-NF. This new approach of deposition and in situ exfoliation by using liquid crystal template and hydrogen bubbles offers a new platform to nanostructuring wide range of catalysts with better catalytic performance. [ABSTRACT FROM AUTHOR]

Electrochemical properties of nickel on a gold disk electrode from aqueous hexagonal lyotropic liquid crystalline phase in Brij 78 as supporting electrolyte through the electrochemical techniques of cyclic voltammetry (CV) and convolution -deconvolution voltammetry, coupled with method of digital simulation was investigated. Scan rate effect on the peak height and on the peak position was indicated. It was found that scanning the potential in the cathodic direction produced two peaks, corresponding to the reduction of Ni2+ to Ni metal. Also reversing the potential to the anodic direction was characterized by nickel dissolution. [ABSTRACT FROM AUTHOR]

Highlights: [•] Embedding of CNTs in the mesoporous titania (MT) showed high photoactivity. [•] Embedding of CNTs in the nanophase titania protected the mesoporous framework. [•] Embedding of CNTs in the nanophase titania inhibited undesirable grain growth. [•] Embedding of CNTs in the nanophase titania suppressed phase transformation. [•] Embedding of CNTs in the nanophase titania increased the thermal stability of MT. [Copyright &y& Elsevier]

Abstract: Advances in the nanoscale design of polymeric, “soft” materials and of metallic, “hard” materials can converge at the “interfaces” to form hybrid nanomaterials with interesting features. Novel optical, magnetic, electronic, and catalytic properties are conferred by metal nanoparticles, depending on their morphology (size and shape), surface properties, and long-range organization. We review here the utilization of block copolymers for the controlled synthesis and stabilization of metal nanoparticles. Solvated block copolymers can provide nanoscale environments of varying and tunable shape, dimensions, mobility, local polarity, concentration, and reactivity. In particular, block copolymers containing poly(ethylene oxide) can exhibit multiple functions on the basis of their organization at the intra-polymer level (i.e., crown ether-like cavities that bind and reduce metal ions), and at the supramolecular level (surface-adsorbed micelles, and ordered arrays of micelles). These block copolymers can thus initiate metal nanoparticle formation, and control the nanoparticle size and shape. The physically adsorbed block copolymers, which can be subsequently removed or exchanged with other functional ligands, stabilize the nanoparticles and can facilitate their integration into diverse processes and products. Block copolymers can be further useful in promoting long-range nanoparticle organization. Several studies have elucidated the nanoparticle synthesis and stabilization mechanism, optimized the conditions for different outcomes, extended the ranges of materials obtained and applications impacted, and generalized the scope of this functional polymer-based nanoparticle synthesis methodology. [Copyright &y& Elsevier]

Abstract: This work reports the directional growth of macroscopic ceramic needles by combining a thermo-responsive sulfated hydroxy zirconyl (SHZ) hydrosol with a swollen hexagonal liquid crystal (SHLC). The effect of the molar ratio R s =[Zr4+]/[SO4 2−] on the thermo-stability of both the SHZ hydrosol and the SHLC, and also on the nucleation and 1D-growth of ceramic particles was investigated. The dynamics of the thermo-induced aggregation growth process was monitored in situ by rheological property measurements. The results show that by increasing the R s, the kinetic stability of the system in the sol state increases, leading to the formation of a less branched framework during the thermo-induced aggregation process. Furthermore, the small-angle X-ray diffraction (XRD) results show that the thermo-stability of the SHLC employed as soft template is improved by increasing the R s. Both effects allow us to induce the particle''s nucleation by heating the SHLC template to a moderate temperature (≈50°C), while the kinetics of the needle''s growth is enhanced by increasing the [Zr4+]/[SO4 2−] molar ratio. [Copyright &y& Elsevier]

Abstract: Novel ordered mesoporous cobalt hydroxide films have been successfully electrodeposited on different substrates, i.e., foamed nickel mesh and titanium plate, from cobalt nitrate dissolved in the aqueous domains of the hexagonal lyotropic liquid crystalline phase of Brij 56. Field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM) studies present that the as-deposited films have an interlaced nanosheet-like surface morphology and possess a regular nanostructure with hexagonal arrays of pores of nanometer dimension and extended periodicity. Various electrochemical test results show that the films on both substrates exhibit excellent electrochemical capacitive behavior due to the special ordered mesoporous nanostructure. Furthermore, it is obvious that the ordered mesoporous cobalt hydroxide film on foamed Ni mesh has much higher specific capacitance (maximum: 2646Fg−1) than that of the film on Ti plate (maximum: 1018Fg−1), which is mainly because that the foamed Ni mesh substrate with much larger surface area than Ti plate could enhance the utilization and the capacitance of Co(OH)2 film greatly. [Copyright &y& Elsevier]

Abstract: Novel ordered mesoporous cobalt hydroxide film (designated HI-e Co(OH)2) has been successfully electrodeposited from cobalt nitrate dissolved in the aqueous domains of the hexagonal lyotropic liquid crystalline phase of Brij 56. Experimental electrodeposition parameters such as deposition potentials and deposition temperatures are varied to analyze their influences on the electrochemical capacitor behavior. The films are physically characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to determine the effects of deposition potentials and temperatures on the surface morphology and nanostructure. Electrochemical techniques such as cyclic voltammetry (CV) and chronopotentiometry are applied to systematically investigate the effects of deposition potentials and temperatures on the capacitance of the films. The results demonstrated that the capacitive performance of the HI-e Co(OH)2 film achieved the highest value when it is electrodeposited at −0.75V under the deposition temperature of 50°C. [Copyright &y& Elsevier]

Abstract: Mesoporous anatase with spherical, rodlike and lamellar morphologies was synthesized by a modified sol–gel method using titanium tetrabutoxide (TBOT) as metal precursor. Polarization microscope (PLM) study indicates that final morphologies are similar to lytropic liquid crystalline structure formed during gelation, and the colloidal phase separation mechanism is used to explain the phenomenon. [Copyright &y& Elsevier]

This work reports the synthesis of nickel/nickel hydroxides nanoflakes (Ni/Ni(OH) 2 -NFs) at room temperature via a novel chemical deposition and exfoliation from a liquid crystal template mixture. The nickel ions dissolved in the interstitial aqueous domain of the Brij®78 hexagonal liquid crystal template were deposited by a reducing agent of sodium borohydride that concurrently reduces the nickel ions and generates extreme hydrogen gas bubbles, that exfoliated the nickel/nickel hydroxide layers. The Ni/Ni(OH) 2 -NFs crystal structure, morphology, and surface area characterizations revealed the formation of semi-crystalline α-Ni(OH) 2 nanoflakes with a thickness of approximately 10 nm and a specific surface area of about 135 m2/g. The electrochemical measurements of cyclic voltammetry, chronoamperometry, and impedance analysis showed that the Ni/Ni(OH) 2 -NFs exhibited significant performance for the glucose non-enzymatic oxidation in an alkaline solution in comparison to the bare -nickel hydroxide (bare -Ni(OH) 2) deposited without surfactant. The Ni/Ni(OH) 2 -NFs electrode showed superior glucose oxidation activity over the bare -Ni(OH) 2 catalyst with a sensitivity of 1.078 mA mM−1 cm−2 with a linear concentration dependency range from 0.2 to 60 mM and a detection limit of 0.2 mM (S/N = 3). The enhanced electrochemical active surface area and mesoporosity of the 2D nanoflakes make the Ni/Ni(OH) 2 -NFs a promising catalyst in the application of glucose non-enzymatic sensing. [ABSTRACT FROM AUTHOR]

Porous sulfated zirconia was prepared using a sol-gel process associated with liquid crystal templates (LCTs). Evaluation was made of the effects of the Zr4+:SO 4 2− molar ratio and aging time on the formation and stability of the lyotropic arrangement of the LCT gel and the features of the resulting mesoporous powders. Polarized light microscopy and small-angle X-ray diffraction (SAXD) analysis of the LCT gel revealed the prevalence of hexagonal mesophase (P6mm) in the sulfated samples. Thermal treatment of the samples resulted in sulfated ZrO 2 ceramic powders whose infrared spectra exhibited bands characteristic of mono- and bi-dentate SO 4 2− groups bonded to ZrO 2. X-Ray diffractograms of the materials showed a mixture of monoclinic and tetragonal phases of zirconia, with the tetragonal phase increasing from 86–90% to 100% as the Zr4+:SO 4 2− molar ratio decreases from 15 to 5. Crystallite sizes of about 9.5 and 4.5 nm were observed for the pristine and sulfated zirconia (Zr4+:SO 4 2− = 5), respectively. The lattice fringe distances observed for selected areas in the electron diffraction patterns and in high-resolution transmission electron micrographs confirmed the mixture of tetragonal and monoclinic crystalline phases. Small-angle X-Ray scattering analysis showed that the gyration radius was around 2 nm and that the particles were organized as a branched network with a fractal surface when sulfate was inserted in the zirconia structure, improving its porous characteristics. The LCT generated pores with greater diameters (up to 4.4 nm) in the sulfated samples, while the surface area increased to 146 m2 g−1. The gel aging process led to the reinforcement of the pore wall structure, prevented shrinkage effects during calcination, and enabled higher surface areas to be achieved. Scanning and transmission electron microscopy analyses showed that the walls of the pores were composed of platelets of irregular shapes, giving rise to mesopores. The porous structure, combined with the presence of acid sites, improved by sulfate groups at the surface of tetragonal zirconia crystallite, makes these materials promising candidates for application as catalysts in dehydration reactions. [ABSTRACT FROM AUTHOR]