pH Value Of Precursor Solution Research Articles

Effective abatement of naphthalene from flue gas by V-W/Ti catalyst: Study of vanadium species and reaction mechanism

The removal of naphthalene is important but deficient, so that the available V-W/Ti catalysts (1.0 wt% V2O5/TiO2) were prepared for its efficient abatement in this work. Especially, influences of different existence status of vanadium species on naphthalene elimination were investigated via changing the pH value of precursor solution. With the increase of precursor solution acidity, more highly polymeric vanadium species were formed on the catalyst surface. The redox capability was enhanced markedly as a consequence of the stronger electron transfer between V/W and Ti that induced more surface active oxygen and V5+, whereas the catalytic activity was obviously boosted and almost 90 % conversion of naphthalene was achieved at 293 °C. Moreover, the weaker chemisorption between naphthalene and V-W/Ti catalyst allowed the deeper conversion to COx. GC–MS manifested that naphthalene seemed to be an organic component that was difficult to be totally degraded. Naphthalene oxidation was in the following pathway of naphthalene → 1,4-naphthoquinone → phthalic anhydride → phthalates → benzene → benzoquinone → maleic anhydride → COx/H2O. The opening of aromatic ring in phthalic anhydride and benzene ring in benzene were proven to be the rate-controlling step based on in-situ DRIFTS results. The key of naphthalene oxidation was the complete degradation of various intermediates.

Controlled Growth of WO3 Photoanode under Various pH Conditions for Efficient Photoelectrochemical Performance.

Herein, the effects of the precursor solution's acidity level on the crystal structure, morphology, nucleation, and growth of WO3·nH2O and WO3 nanostructures are reported. Structural investigations on WO3·nH2O using X-ray diffraction and Fourier-transform infrared spectroscopy confirm that the quantity of hydrate groups increases due to the interaction between H+ and water molecules with increasing HCl volume. Surface analysis results support our claim that the evolution of grain size, surface roughness, and growth direction on WO3·nH2O and WO3 nanostructures rely on the precursor solution's pH value. Consequently, the photocurrent density of a WO3 photoanode using a HCl-5 mL sample achieves the best results with 0.9 mA/cm2 at 1.23 V vs. a reversible hydrogen electrode (RHE). We suggest that the improved photocurrent density of the HCl-5 mL sample is due to the efficient light absorption from the densely grown WO3 nanoplates on a substrate and that its excellent charge transport kinetics originate from the large surface area, low charge transfer resistance, and fast ion diffusion through the photoanode/electrolyte interface.

Synthesis of Ag3PO4/Ag4P2O7 by microwave-hydrothermal method for enhanced UV–visible photocatalytic performance

Ag3PO4/Ag4P2O7 photocatalysts were successfully synthesized by microwave-hydrothermal method. Tuning the properties of photocatalysts was achieved using different amount of acetic acid (CH3COOH) and sodium hydroxide (NaOH) to adjust pH value of precursor solution (pH = 4, 7, 10 and 12). The crystal structure, morphology and optical property of samples were characterized and explained. The photocatalytic activity of sample was determined by degradation of rhodamine B (RhB) and methyl orange (MO) under a wavelength range of 350–700 nm irradiation. The results demonstrated that the change in shape of particles was not observed whereas the average particle size was decreased with increasing pH value because of the high hydroxide ions (OH−). The sample synthesized in the solution with the pH of 10 exhibited excellent photocatalytic performance and stability because of the highest surface area and the present of Ag4P2O7 on the surface of particles. The highest photodegradation efficiency was 99.34 and 96.12% by degrading RhB and MO, respectively. The enhancement of photocatalytic performance of Ag3PO4/Ag4P2O7 was discussed. The active species trapping experiments showed that the h+ was the main active species to decompose the dye molecules.

Effect of pH values on the structural, morphological and sensing properties of ZnO nanostructure

In the present investigation ZnO thin films have been prepared by sol-gel spin coating technique with different pH values. The effect of pH values of precursor solution on the crystal structural, morphological and humidity sensing properties of ZnO nanostructures have been investigated using different characterization technique. The crystal structure and phase analysis has been examined by powder X-ray diffraction (PXRD) technique. The PXRD pattern clearly revealed the ZnO thin films have hexagonal wurtzite crystal structure. The average crystallite size of ZnO thin films have been calculated using Scherer formula and found to be ~24 nm to ~30 nm. The microstrain (ɛa) and (ɛc) of ZnO thin films for different pH values 8 and 11, have been calculated and found to be 7.59, 0.1017; 7.57, 0.1094 respectively. The scanning electron microscopy (SEM) image depicts the formation of spherical nanostructurewith diameter range 80 to 95 nm distributed throughout the surface. The atomic force microscopy (AFM) image also shows the spherical nanostructureconsistently distributed throughout the surface with diameter range 75 to 80 nm.It was also found that increasing the pH values from 8 to 11 modified the grains and grains boundary. The humidity sensing properties of ZnO thin films prepared from pH values of 8 to 11 and found to be lower hysteresis loss, less aging effect and good sensitivity in the range of 8.37 MΩ/%RH to 12.25 MΩ/%RH respectively

Controlling crystal structures of vanadium oxides via pH regulation and decoupling crystallographic perspective on zinc storage behaviors

Rechargeable aqueous zinc–ion batteries (RAZIBs) hold tremendous promise for large–scale energy storage applications on account of high materials abundance, cost–effectiveness, and intrinsic safety. To date, vanadium–based oxides have been widely investigated as promising candidates for RAZIBs. The crystal structure of vanadium oxide plays a decisive role in determining Zn2+ storage behavior. In this work, we reveal that vanadium oxides with various crystal structures can be obtained from different V5+ solute species by controlling the pH value of the precursor solution. The results indicate that layered Zn0.15V2O5·0.76H2O obtained at pH = 1 exhibits reduced charge−transfer resistance and promoted Zn2+ transport kinetics. As a result, the sample demonstrates remarkable Zn2+ storage capability, that is, high capacity (320 mAh g–1 at 1 A g–1), promising rate capability (227 mAh g–1 at 8 A g–1), and reliable cycle performance (184 mAh g–1 after 3000 cycles at 4 A g–1). Controlling the pH value of precursor solution to 4 and 6, the samples are characterized as mixed–phase compounds containing ‘‘inactive’’ components (ZnV2O6 and/or water−deficient (NH4)2V6O16), leading to inferior electrochemical performance. For the pH = 10 sample, the obtained Zn2(OH)3VO3 is unfit for Zn2+ storage with negligible capacity. The reaction chemistries of vanadium oxides and the crystallographic perspective on Zn2+ storage properties are revealed, providing a new insight into the development of high−performance cathodes for RAZIBs.

PH-induced structural evolution, photodegradation mechanism and application of bismuth molybdate photocatalyst

In this work, we have elucidated the pH-induced structural evolution of bismuth molybdate photocatalyst based on a hydrothermal synthesis route. With increasing the pH value of precursor solution, pure Bi2MoO6 was synthesized at pH 2–5, Bi2MoO6-Bi4MoO9 mixture was obtained at pH 7–9, pure Bi4MoO9 was obtained at pH 11, and pure α-Bi2O3 was derived at pH 13. The as-derived samples mainly present particle-like shapes but with different particle sizes (except the observation of Bi2MoO6 nanowires in sample S-pH9). The photocatalytic performances between the samples were compared via the degradation of methylene blue (MB) under irradiation of simulated sunlight. The Bi2MoO6 sample synthesized at pH 2 exhibited the highest photodegradation performance (η(30 min) = 89.8 %, kapp = 0.05007 min−1) among the samples. The underlying photocatalytic mechanism and degradation pathways of MB were systematically analyzed. Moreover, the photodegradation performance of the Bi2MoO6 photocatalyst was further evaluated at different acidic-alkaline environments as well as in degrading various color and colorless organic pollutants, which provides an important insight into its practical application.

Densely packed Ga2O3 nanostructured film via pH-controlled crystal growth and memristive properties

Gallium Oxide (Ga2O3) nanostructured film is deposited via a single step aqueous method by controlling the pH value of precursor solution. The uniformity, density and crystallite size varies when the pH of precursor solution changes from pH 6 to pH 9. The as-deposited nanostructured film is present in hydroxide crystalline phase which gets converted to a mixed phase (‘α’ and ’β’) when heat treated at 600 ​°C. The densely packed Ga2O3 nanostructured film (at pH 8) shows better electrical conductivity and stable current density of 10−8 A/cm2. The memristive measurement for densely packed nanostructured film results in ROFF/RON ratio in order of 102, whereas the Vset and Vreset values are observed to be 2.7V and −3.1V respectively. This single step process is suitable for deposition of good quality, large crystallite, densely packed nanostructured Ga2O3 films that can be utilized in various electronic and optoelectronic applications.

Improvement of humidity sensing performance and dielectric response through pH variation in CaCu3Ti4O12 ceramics

The internal barrier layer capacitors mechanism of CaCu3Ti4O12 (CCTO) ceramics contribute a colossal dielectric constant within it. However, the enormous dielectric loss limits its application in devices. In this work, we have improved the dielectric response of CCTO by adjusting the pH value of precursor solution during the synthesis process, followed by a relatively shorter period of sintering. The synthesized powders were characterized by XRD, FESEM, UV-Vis DRS, PL, and micro-Raman measurement techniques to study the structural, morphological, optical, and lattice vibration properties of the powder. A systemic investigation of the humidity sensing characteristics of all the samples was done at five different frequencies viz—100 Hz, 120 Hz, 1 kHz, 10 kHz, and 100 kHz. As the relative humidity (RH) changes from 33% to 95%, the dielectric constant of the CCTO based sensor increases approximately by 343%. The prepared ceramic also possesses a low dielectric loss (tanδ~ 0.32 at 95% RH), linear response (linearity-0.988), and good stability. This report investigates the various contributing factors responsible for different humidity sensing responses and correlates them with the various experimental results obtained by characterizing the prepared samples. The significantly enhanced dielectric response at room temperature makes the pH-adjusted CCTO powder a multifunctional material for humidity sensors and energy storage devices.

Morphology-dependent thermoelectric properties of mixed phases of copper sulfide (Cu2−xS) nanostructures synthesized by hydrothermal method

In this research work we have synthesized copper sulfide (Cu2−xS) nanostructures by the hydrothermal method. The post-sulfurization was performed by using tube furnace to reduce sulfur deficiency and to minimize impurities present in the crystal-lattice. The samples were synthesized by various pH values of precursor solution. The samples were characterized by XRD, RAMAN spectroscopy, SEM, Hall measurements and Seebeck effect. XRD analysis revealed the formation of hexagonal covellite (CuS) and chalcocite (Cu2S) phases of copper sulfide. Despite these phases XRD data also showed the dominating hexagonal digenite (Cu1.8S) phase of copper sulfide. We observed a decreasing trend in average crystalline size with the increasing pH values of the samples from the XRD data. We have found maximum average crystalline size of 39.1679 nm at pH value of 4. The formation of LO mode of hexagonal covellite phase of copper sulfide was observed from RAMAN analysis. The SEM images revealed the formation of flower-like nanostructures at the lowest pH value. It strengthened our argument that the crystallinity of nanostructures is inversely proportional to the pH value. We have achieved maximum values of Seebeck coefficient and conductivity at room temperature as 73.920 µV/K and 0.909 S/cm, respectively. The Seebeck coefficient and conductivity graphs showed an increasing trend due to the energy filtering effect in mesoporous structure. The maximum value of power factor was 4.91 × 10–7 Wm−1 K−2.

Enhanced energy storage ability of UIO66 active material on acid-treated carbon cloth for flexible supercapacitors

Metal organic framework, UIO66, has been regarded as one of potential electroactive materials for supercapacitors (SC), due to high surface area and tunable pore structures. To further improve electrochemical performance of UIO66-based SC, morphology design of UIO66 is necessary. In this work, it is the first time to study the effects of pH value of precursor solution on physical and electrochemical properties of UIO66. The pH values of 1, 2, 4 and 6 of precursor solution is prepared using acetic acid which is also acts as structure-directing agent. The different sizes of UIO66 are obtained by merely changing pH value of precursor solution. The UIO66 octahedron synthesized using pH values of 1 and 6 present the smallest size and similar dimensions to carbon black with irregular spherical morphology and size of around 75 nm which is also in paste. Carbon cloth (CC) substrate is also modified using acid to understand substrate influences on SC performance. The optimized pH value of 1 and 6 is respectively obtained for synthesizing UIO66 on acid-treated CC (ACC) and CC substrates. Due to the extra energy storage from substrate, the electrode with UIO66 prepared using pH value of 6 on ACC (M6/ACC) shows the highest areal capacitance (CA) of 3.87 mF/cm2 at 2.5 A/g. Also, the symmetric SC (SSC) fabricated using M6/ACC electrodes and aqueous medium-based electrolyte shows potential window of 0.9 V, maximum energy density of 36 mWh/kg at 89.94 W/kg, and CA retention of 130% after 10000 times charging and discharging process.

Epitaxial growth of MnFe2O4 nanosheets arrays for supercapacitor

Due to its isotropic growth habit, preparation of well-defined MnFe2O4 arrays is still a great challenge. In this paper, the MnFe2O4 nanosheets arrays (MFONSAs) have been successfully fabricated on Ni foam (NF) by immersing the NF into the precursor solution and subsequent hydrothermal treatment. According to the results of the control experiments, the pH value of precursor solution has significant effect on the formation of MFONSAs. When the pH is 13, a layer of Ni(OH)2 nanoarrays will be grown on the surface of NF during the immersion process by in situ etching. The (404) and (311) facets of MnFe2O4 will be subsequently growth along with the (111) and (101) facets of Ni(OH)2 seeds by epitaxial growth in the following hydrothermal treatment and well-defined MFONSAs can be obtained. When evaluated as a supercapacitor electrode, the as-prepared MFONSAs exhibit an ultrahigh specific capacity of 302.6 mC cm−2 under the current density of 1 mA cm−2. Furthermore, the asymmetric supercapacitors (ASCs) based on as-obtained MFONSAs cathode and actived carbon (AC) anode displayed an excellent electrochemical behavior with a high energy density of 68.7 mWh cm−2 at 587 mW cm−2 and superior cyclic stability. For a practical application test, a light-emitting diode was immuinated for 50 s by an ASC with only charged 10 s, which demonstrated a potential electrode material in supercapacitor.

Enhancing the cycling stability of all-solid-state lithium-ion batteries assembled with Li1.3Al0.3Ti1.7(PO4)3 solid electrolytes prepared from precursor solutions with appropriate pH values

NASICON-type solid electrolyte powders Li1.3Al0.3Ti1.7(PO4)3 (LATP) are synthesized by spray-drying and assisted sintering processes. The effects of different pH values of the spray-dried precursor solution on the crystallinity, morphology, ionic conductivity, compaction density and cycling stability of the LATP solid electrolyte sheets are investigated. The LATP-6.0 solid electrolyte sheets present the most perfect microstructure with a compaction density of 2.968 g cm−1 and the highest ionic conductivity of 1.182 E−4 S cm−1 with an activation energy of 0.273 eV at room temperature when the pH value of the precursor solution is adjusted to 6.0. Additionally, the assembled LiCoO2/LATP-6.0/Li all-solid-state coin cell delivers commendable cycling stability with a high discharge specific capacity of 150.5 mAh g−1 at 0.1 C after five activation cycles and retains a specific capacity retention rate of 94.28% after 300 cycles with various current densities at room temperature. Moreover, the LATP-6.0 solid electrolyte sheets maintain an intact morphology and uniformly-distributed elements composition after cycling. Based on these excellent results, the use of the LATP-6.0 sheets as solid electrolytes in high-performance all-solid-state lithium-ion batteries is a promising strategy.

Enhanced piezoelectric response of (Ba,Ca)(Ti, Zr)O3 ceramics by super large grain size and construction of phase boundary

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics with super large grain size (>50 μm) have been successfully fabricated by sol-gel method. The effects of pH value of precursor solution on microstructure, electric properties and fatigue behavior were systematically studied. BCZT ceramics with super large grain size (35–55 μm) were prepared by BCZT powders with large particle size (136–221 nm) by controlling the pH value. The grain size and densification of BCZT ceramics decrease with the increase of pH value of precursor solution. XRD results indicate that there is the coexistence of rhombohedral and tetragonal phase in BCZT ceramics synthesized by precursor solution with a pH of 3 and are the coexistence of orthorhombic and tetragonal phase in BCZT ceramics synthesized by precursor solution with a pH of 5 and 7. BCZT ceramics shows obvious diffuse ferroelectric-paraelectric phase transition characteristic and the diffuseness behavior enhances as the pH value increases. The remnant polarization and coercive electric field of BCZT ceramics reduce with the decreased grain size caused by the increase of pH value. The excellent piezoelectric properties (d33 = 585.6 pC/N and d33∗ = 898 pm/V) of BCZT ceramics have been obtained by super large grain size and the construction of phase boundary of tetragonal phase and orthorhombic phase. Furthermore, BCZT ceramics with large grain size still has high fatigue resistance to bipolar electric cycling.

Hydrothermal Synthesis of PAA-Coated NaYF4:Yb3+, Er3+ Nanophosphors with Predicted Morphology, Phase and Enhanced Upconversion Luminescence Properties

In this study, well-defined PAA-coated NaYF4:Yb3+, Er3+ nanophosphors were synthesized via a poly(acrylic acid) (PAA) mediated hydrothermal process. The rational control of initial reaction conditions, such as hydrothermal temperature, pH value of precursor-solution, added amount of PAA, and molecular weight of PAA ligand, resulted in upconversion of NaYF4:Yb3+, Er3+ phosphors with varying crystal phases (α and β) and morphologies (e.g., nanosphere, submicrorod, microrod, microtube, and microprism). By assessing the upconversion luminescent properties of the synthesized NaYF4:Yb3+, Er3+ phosphors upon excitation by 980 nm infrared light, it was demonstrated that the β-phase NaYF4:Yb3+, Er3+ phosphors generally presented stronger upconversion luminescent than α-phase NaYF4:Yb3+, Er3+ phosphors and orthorhombic phase of YF3:Yb3+, Er3+ sample. Additionally, the β-phase NaYF4:Yb3+, Er3+ phosphors with hollow microtube morphology presented higher upconversion luminescent intensity than phosphors of other morphologies. This may be due to microtubes having larger surface area (inner and outer surfaces), which promoted the absorption efficiency under similar excitation conditions, therefore generating higher luminescent intensity. Findings form this study suggest for precisely controlled growth of other complex rare earth fluoride compounds and provide a reference for exploration of component-, phase- and morphology-dependent upconversion luminescence properties.

Highly stable and sensitive resistive flexible humidity sensors by means of roll-to-roll printed electrodes and flower-like TiO2 nanostructures

Titanium dioxide (TiO2) nanostructure is synthesized and utilized as a sensing material in flexible resistive humidity sensors. The morphology of TiO2 flower-like nanostructure was optimized to possess high surface area by controlling pH value of precursor solution. The electrode was roll-to-roll gravure printed, and synthesized TiO2 nanoflower and protective layer were drop cast on flexible polyimide substrate. The humidity sensor made of TiO2 nanoflower with highest surface area exhibited highest sensitivity of 485.7 RH%−1. Furthermore, it showed comparably good repeatability, little hysteresis, and high degree of chemical stability as well as excellent resistance to random mechanical deformation. High sensitivity and stability of sensors based on TiO2 nanoflower hierarchical structure make them suitable for flexible and/or wearable applications.

Preparation of a novel red KBaGd(MoO4)3:Eu3+ phosphor by sol-gel method and its luminescent properties

For the first time, KBaGd(MoO4)3:Eu3+ phosphors were synthesized by sol-gel method and its structure, morphology and luminescent properties were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), excitation and luminescent spectra. The results show that shape and the particle size distribution of samples synthesized by sol-gel method were more regular and narrower than those synthesized by solid state method. Under the excitation of near UV light (395 nm), an intensive red emission band around 617 nm corresponding to the transition of 5D0→7F2 was observed. The effects of the dose of citric acid, pH value of precursor solution and concentration of Eu3+ ions on the morphology and luminescent properties of the samples were also analyzed. The phosphors show the highest emission intensity as the molar ratio of citric acid to metal ions (C:M) was 2:1, and the optimum concentration of Eu3+ was x = 0.8. The thermal stability of the KBaGd0.2(MoO4)3:0.8Eu3+ phosphor was investigated in the framework of crossover mechanism, and the activation energy was determined to be 0.264eV. Lastly, a red LED was fabricated using the as-synthesized phosphor and its luminescent performances were investigated.

Hydrothermal synthesis of Ni-Co-Cu alloy nanoparticles from low nickel matte

Ni-Co-Cu alloy nanoparticles were synthesized using a hydrothermal method from the low nickel matte. The effects of synthetic parameters such as hydrothermal temperature, pH value of precursor solution, added amount of PVP and reaction time on the chemical compositions, micromorphology and magnetic properties of the prepared products were systematically investigated by X-ray fluorescence (XRF), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), High-resolution TEM (HRTEM) and Vibrating sample magnetometer (VSM). It is indicated that the size of as-prepared Ni-Co-Cu alloy nanoparticles decreased with the increasing of reaction temperature (150 °C-180 °C), pH value (10.0–12.0) and the added amount of PVP (0–1.0 g mL−1). Under the optimal experimental conditions, pure Ni-based alloy (Ni0.95Co0.03Cu0.02) which exhibited good magnetic properties with the saturation magnetization (Ms) value of 48.72 emu g−1 and the coercivity (Hc) value of 126.39 Oe, respectively, was achieved. Moreover, the main impurity ions, such as Fe ions in the leaching solution of low nickel matte, have no effect on the purity of as-prepared alloy nanoparticles. This paper may provide a new way for the synthesis of alloys from natural minerals for the first time.

Anatase TiO2 nanocrystals via dihydroxy bis (ammonium lactato) titanium (IV) acidic hydrolysis and its performance in dye-sensitized solar cells

The conventional way to synthesize anatase TiO2 with dihydroxy bis (ammonium lactato) titanium (IV) (TALH) is adjusting pH value of precursor solution to basic condition. In this paper, we prepared white color anatase TiO2 under acid condition via a hydrothermal route. TEM image shows the TiO2 has a sharp contour and crystallite size is about 5–10 nm. The TiO2 also has specific surface area of 97 m2/g and its average pore diameter is about 8.5 nm after sintering at 500 °C for 30 min. These characters make it to be a proper candidate for DSSCs’ photoanode. By comparing the DSSCs’ performance between the TiO2 we have synthesized (A35) and P25, A35 has energy conversion efficiency of 6.92% without any scattering layers, which was 17.9% higher than P25 photoanode. The higher specific area and good pore diameter distribution of A35 make photoanode absorb more dye molecules. The IPCE curve and dye absorbing experiment further confirmed the above mentioned results. DSSCs’ analysis revealed the white color anatase TiO2 could be achieved under acid condition when using TALH precursor.

具有均一尺寸球形碳气凝胶的制备及其储能研究

用不同pH的碳酸钠溶液作为催化剂催化间苯二酚和甲醛的缩聚反应得到有机凝胶，后经高温碳化得到碳气凝胶。采用SEM、TEM和N2吸脱附测试方法对所得材料进行表征，还通过循环伏安法和恒流充放电测试手段对其电化学性能进行详细的研究。SEM测试结果表明，随着pH数值的增加，所得碳气凝胶颗粒的形貌呈现出由独巨体到球形再到独巨体的变化过程，表明通过调节催化剂的pH可以得到不同形态的碳气凝胶，并且当pH为10.49时所得碳气凝胶材料具有尺寸均一的连续球形结构。N2吸脱附测试结果表明所得球形碳气凝胶材料的比表面积可达526.1 m2/g。循环伏安法和恒流充放电法的测试结果表明同独巨体碳气凝胶相比，粒径高度均一的球形碳气凝胶具有更优异的电化学性能，材料的比电容可以达到85.39 F/g，以其构建的超级电容器比电容可以达到76.72 F/g。 Different pH values of sodium carbonate solution were used as catalyst for condensation of resorcinol and formaldehyde to obtain organic gels. After high temperature carbonization, the organic gels were transformed to carbon aerogels. The obtained materials were characterized by SEM, TEM and N2 adsorption desorption test. In addition, the electrochemical performance, such as cyclic voltammetry and galvanostatic charging and discharging tests, was also conducted. SEM results show that the morphologies of carbon aerogels exhibit the transformation from sole macrosomia to sphere and eventually to sole macrosomia via elevating the pH value of precursor solution. It can be noted that different forms of carbon aerogels can be obtained via regulating the pH of the precursor solution. Especially, when the pH of sodium carbonate solution is 10.49, the prepared carbon aerogels exhibit spherical structure with uniform particle size. N2 adsorption and desorption tests show that the specific surface area of the spherical carbon can up to 526.1 m2/g. Cyclic voltammetry and galvanostatic charging and discharging tests show that the uniformly spherical carbon aerogels expressed more superior electrochemical performance than that of resulted monolithic based carbon aerogels. The specific capacitance of the spherical carbon aerogels can reach 85.39 F/g. Meanwhile, the specific capacitance of spherical carbon aerogels based supercapacitor can get 76.72 F/g.

The synthesis and the photocatalytic degradation property of the nano-MoS2

Recently, the two-dimensional molybdenum disulfide (MoS2) materials have attracted much interest owing to its potential application in optoelectronics and catalyze. In this paper, nano-MoS2was prepared via a hydrothermal method through changing the pH value of the precursor solution. The structure and optical properties are systematically studied. The results indicate that laminated MoS2structure is obtained. The pH value of precursor solution affects the laminated structure. The strong absorption in ultraviolet range and blue emission are observed in the prepared MoS2structures. The photocatalytic properties of MoS2by degrading Rhodamine B under ultraviolet light were observed.