Synthesis, Characterisation, and Photocatalytic Behaviour of Mesoporous ZnS Nanoparticles Prepared Using By-Product Templating

2017 ◽  
Vol 70 (10) ◽  
pp. 1099 ◽  
Author(s):  
Hosein B. Motejadded Emrooz ◽  
Ali R. Rahmani ◽  
Francisco J. Gotor
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Diffuse Reflectance Spectroscopy ◽  
High Surface ◽  
Ultrasonic Waves ◽  
Soft Template ◽  
Bandgap Energy ◽  
Zns Nanoparticles

High surface area mesoporous ZnS nanoparticles (MZN) were obtained with the aid of the by-product of the synthesising reaction. This by-product, namely NaNO3, can be considered as a soft template responsible for the formation of pores. Ethanol and water were chosen as the synthesis media. Ultrasonic waves were used as an accelerator for the synthesis of MZNs. Photocatalytic activities of the synthesised samples for the degradation of methylene blue (MB) were investigated under ultraviolet irradiation. Synthesised specimens were characterised using field emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, diffuse reflectance spectroscopy, N2-physisorption, and FT-IR spectroscopy. Results indicated that the synthesis media has a pronounced effect on the surface properties of the final porous particles by several mechanisms. The specific surface area of the MZN samples synthesised in water and ethanol were determined to be 53 and 201 m2 g−1, respectively. The difference in the specific surface area was attributed to the weak solvation of S2− ions (Na2S·5H2O in ethanol) and also to the by-product of the synthesis reaction. The photocatalytic behaviour of the mesoporous ZnS nanoparticles synthesised in these two media were investigated and the results have been interpreted with the aid of effective surface area, pore volume, and bandgap energy of the specimens.

scholarly journals Adsorption of pharmaceuticals from aqueous solutions using biochar derived from cotton gin waste and guayule bagasse

Biochar ◽  
2020 ◽  
Author(s):  
Marlene C. Ndoun ◽  
Herschel A. Elliott ◽  
Heather E. Preisendanz ◽  
Clinton F. Williams ◽  
Allan Knopf ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Functional Groups ◽  
Specific Surface Area ◽  
High Surface ◽  
Strong Interactions ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Cotton Gin Waste ◽  
Cotton Gin

Abstract Biochars produced from cotton gin waste (CG) and guayule bagasse (GB) were characterized and explored as potential adsorbents for the removal of pharmaceuticals (sulfapyridine-SPY, docusate-DCT and erythromycin-ETM) from aqueous solution. An increase in biochar pyrolysis temperature from 350 οC to 700 οC led to an increase in pH, specific surface area, and surface hydrophobicity. The electronegative surface of all tested biochars indicated that non-Coulombic mechanisms were involved in adsorption of the anionic or uncharged pharmaceuticals under experimental conditions. The adsorption capacities of Sulfapyridine (SPY), Docusate (DCT) and Erythromycin (ETM) on biochar were influenced by the contact time and solution pH, as well as biochar specific surface area and functional groups. Adsorption of these pharmaceutical compounds was dominated by a complex interplay of three mechanisms: hydrophobic partitioning, hydrogen bonding and π–π electron donor–acceptor (EDA) interactions. Despite weaker π–π EDA interactions, reduced hydrophobicity of SPY− and increased electrostatic repulsion between anionic SPY− and the electronegative CG biochar surface at higher pH, the adsorption of SPY unexpectedly increased from 40% to 70% with an increase in pH from 7 to 10. Under alkaline conditions, adsorption was dominated by the formation of strong negative charge-assisted H-bonding between the sulfonamide moiety of SPY and surface carboxylic groups. There seemed to be no appreciable and consistent differences in the extent of DCT and ETM adsorption as the pH changed. Results suggest the CG and GB biochars could act as effective adsorbents for the removal of pharmaceuticals from reclaimed water prior to irrigation. High surface area biochars with physico-chemical properties (e.g., presence of functional groups, high cation and anion exchange capacities) conducive to strong interactions with polar-nonpolar functionality of pharmaceuticals could be used to achieve significant contaminant removal from water. Graphic Abstract

Polyhedral oligomeric silsesquioxane as a recyclable soft template to synthesize mesoporous polymeric carbon nitride with enhanced photocatalytic hydrogen evolution

2021 ◽  
Vol 5 (1) ◽  
pp. 112-116
Author(s):  
Zhiwei Liang ◽  
Lei Liu ◽  
Xiaojia Zhuang ◽  
Zicheng Tang ◽  
Haiping Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Specific Surface Area ◽  
Carbon Nitride ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Soft Template ◽  
Photocatalytic Hydrogen Evolution ◽  
Oligomeric Silsesquioxane ◽  
Polymeric Carbon

A novel recyclable template was used to prepare mesoporous polymeric carbon nitride with prominently increased specific surface area and photoactivity.

Synthesis and Characterization of Porous Mo-W Oxide Nanostructures

2008 ◽  
Vol 8 (12) ◽  
pp. 6445-6450
Author(s):  
F. Paraguay-Delgado ◽  
Y. Verde ◽  
E. Cizniega ◽  
J. A. Lumbreras ◽  
G. Alonso-Nuñez
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Synthesis Method ◽  
Atomic Ratio ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After

The present study reports the synthesis method, microstructure characterization, and thermal stability of nanostructured porous mixed oxide (MoO3-WO3) at 550 and 900 °C of annealing. The material was synthesized using a hydrothermal method. The precursor was prepared by aqueous solution using ammonium heptamolibdate and ammonium metatungstate, with an atomic ratio of Mo/W = 1. The pH was adjusted to 5, and then the solution was transferred to a teflon-lined stainless steel autoclave and heated at 200 °C for 48 h. The resultant material was washed using deionized water. The specific surface area, morphology, composition, and microstructure before and after annealing were studied by N2 physisorption, scanning electron microscopy (SEM), analytical transmission electron microscopy (TEM), and X-Ray diffraction (XRD). The initial synthesized materials showed low crystallinity and high specific surface area around (141 m2/g). After thermal annealing the material showed higher crystallinity and diminished its specific surface area drastically.

scholarly journals Combination of mesoporous titanium dioxide with MoS2 nanosheets for high photocatalytic activity

2017 ◽  
Vol 19 (2) ◽  
pp. 56-60 ◽  
Author(s):  
Loghman Karimi
Keyword(s):  
Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Dye Degradation ◽  
Hydrothermal Process ◽  
Bet Analysis ◽  
Mesoporous Titanium Dioxide

Abstract This study presents a facile approach for the preparation of MoS2 nanosheet decorated by porous titanium dioxide with effective photocatalytic activity. Mesoporous titanium dioxide nanostructures first synthesized by a hydrothermal process using titanium (III) chloride and then the MoS2/TiO2 were prepared through mixing of MoS2 nanosheet with mesoporous titanium dioxide under ultrasonic irradiation. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) analysis. The results showed that the nanocomposite has mesoporous structure with specific surface area of 176.4 m2/g and pore diameter of 20 nm. The as-prepared MoS2/TiO2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under sunlight irradiation, which could be attributed to synergistic effect between the molybdenum disulfide nanosheet and mesoporous titanium dioxide. The photocatalytic performance achieved is about 2.2 times higher than that of mesoporous TiO2 alone. It is believed that the extended light absorption ability and the large specific surface area of the 2D MoS2 nanosheets in the nanocomposite, leading to the enhanced photocatalytic degradation activity.

Structure and Catalytic Soot Combustion of Perovskite La-Mn-O Hollow Microfibers via Gel-Precursor Transformation Process

2012 ◽  
Vol 538-541 ◽  
pp. 2289-2292
Author(s):  
Xiao Xiao Meng ◽  
Feng Lin He ◽  
Jiang Ying Shen ◽  
Xiang Qian Shen
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Surface ◽  
Thermo Gravimetric Analysis ◽  
Transformation Process ◽  
High Catalytic Activity ◽  
Gravimetric Analysis ◽  
Soot Combustion ◽  
Aspect Ratios

The nanocrystalline perovskite La-Mn-O hollow microfibers were prepared by the gel-precursor transformation process from reagents of metal salts and citric acid. The gel precursor and resultant products were characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The specific surface area was measured by the Brunauere-Emmette-Teller method. The catalytic performance of soot combustion was evaluated by thermo-gravimetric analysis under model conditions. The nanocrystalline La-Mn-O hollow microfibers calcined at 650 °C for 6 h are characterized with diameters of 2-8 µm, aspect ratios (length/diameter) about 5-15, a micro-tunnel with an estimated ratio 1/3 of the hollow diameter to fiber diameter, and a high specific surface area of 36.7 m2/g that is 1.9 times higher than the counterpart nanosized powder. This nanocrystalline La-Mn-O hollow microfibers catalyst exhibit a high catalytic activity for the soot combustion, with a low T50 of 397°C, which is largely owing to the high surface area and the micro-tunnel structure.

CVD Synthesis of Multi-Walled Carbon Nanotubes onto Different Catalysts at Low Temperature

NANO ◽  
2018 ◽  
Vol 13 (04) ◽  
pp. 1850036 ◽  
Author(s):  
Guiqiang Diao ◽  
Hao Li ◽  
Hao Liang ◽  
Iryna Ivanenko ◽  
Tetiana Dontsova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Low Temperature ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Lithium Ion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs) were synthesized onto a series of individual and bimetallic catalysts by the chemical vapor deposition (CVD) of acetylene at low temperature (600[Formula: see text]C). The catalysts were prepared by two methods, i.e., precipitation and sol–gel, with two different carriers – MgO and Al2O3. The catalysts were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric (TG) analysis, low-temperature adsorption of nitrogen. The yield of the MWCNTs was calculated in two ways, while the highest yield of 800% was achieved onto the two-component NiO/Co2O3/MgO catalyst, SEM and transmission electron microscopy (TEM) results confirm that uniform tube-like structure MWCNTs with the yield of 410% were obtained onto Co2O3/Al2O3 catalyst. These MWCNTs are smooth and pointing in the same direction. Their tube diameter is about 20[Formula: see text]nm, which is the smallest around all observed MWCNTs. Moreover, nonuniform curved bamboo-like MWCNTs with nozzles in the yield of 760% were obtained onto NiO/V2O3/MgO catalyst. Their diameter ranges from 25[Formula: see text]nm to 50[Formula: see text]nm. Results show that single-component catalyst promotes the growth of uniform and smaller nanotubes. Among the as-grown nanotubes, their specific surface area increases and average pores diameter reduces after the treatment with concentrated nitric acid at reflux and washing condition. The largest specific surface area (305[Formula: see text]m2/g) and average pores diameter (26[Formula: see text]m2/g) are processed to MWCNTs grown onto the NiO/Co2O3/MgO catalyst. MWCNTs with such large structural adsorption characteristics and purity of more than 99% obtained with yield 800% show potential use for preparation of nanocomposites as anode materials in lithium ion batteries.

scholarly journals N, S-Codoped Activated Carbon Material with Ultra-High Surface Area for High-Performance Supercapacitors

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1982
Author(s):  
Qinghua Yuan ◽  
Zhuwen Ma ◽  
Junbiao Chen ◽  
Zhenrui Huang ◽  
Zeming Fang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Specific Capacitance ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Material ◽  
High Surface ◽  
Koh Activation ◽  
Supercapacitor Electrode ◽  
Tobacco Stalk

The recycling of macromolecular biowastes has been a problem for the agriculture industry. In this study, a novel N, S-codoped activated carbon material with an ultrahigh specific area was produced for the application of a supercapacitor electrode, using tobacco stalk biowastes as the carbon source, KOH as the activating agents and thiourea as the doping agent. Tobacco stalk is mainly composed of cellulose, but also contains many small molecules and inorganic salts. KOH activation resulted in many mesopores, giving the tobacco stem-activated carbon a large specific surface area and double-layer capacitance. The specific surface area of the samples reached up to 3733 m2·g−1, while the maximum specific capacitance of the samples obtained was up to 281.3 F·g−1 in the 3-electrode tests (1 A·g−1). The doping of N and S elements raised the specific capacitance significantly, which could be increased to a value as high as 422.5 F·g−1 at a current density of 1 A·g−1 in the 3-electrode tests, but N, S-codoping also led to instability. The results of this article prove that tobacco stalks could be efficiently reused in the field of supercapacitors.

Effects of dry grinding on pyrophyllite

Clay Minerals ◽  
1988 ◽  
Vol 23 (4) ◽  
pp. 399-410 ◽  
Author(s):  
J. L. Pérez-Rodríguez ◽  
L. Madrid Sánchez del Villar ◽  
P.J. Sánchez-Soto
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Grinding Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dry Grinding ◽  
Scanning Electron ◽  
Area Data

AbstractDry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle size were detected by SEM and XRD, resulting in a large increase in specific surface area, up to a maximum of ∼60 m2·g−1. Marked changes in the structure take place between 30 and 32 mins grinding. Longer grinding times increase the degree of disorder and SEM and specific surface area data suggest that aggregation occurs. XRD results indicate that some residual order persists in the degraded structure.

Sol-gel Synthesis of a Novel χSm2Ti2O7/HZSM-5 Composite Photocatalyst for the Promoted Activity on RBR X-3B Degradation

2017 ◽  
Vol 14 (1) ◽  
pp. 17-25
Author(s):  
Wenjie Zhang ◽  
Jiao Yang ◽  
Ling Du
Keyword(s):  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Pyrochlore Phase ◽  
Bandgap Energy ◽  
Powder Materials ◽  
Sol Gel Synthesis ◽  
Adsorption Desorption

Background: Pyrochloro structured Sm2Ti2O7 has photocatalytic activity on degradation of organic substances and on hydrogen evolution from water. Powder materials usually encounter the obstacle of separating from treated water. HZSM-5 zeolite is a kind of porous structured material with large surface area. Its role as a support for Sm2Ti2O7 is interesting. Methods: The supported Sm2Ti2O7 was synthesized using sol-gel method. The composite χSm2Ti2O7/HZSM-5 was characterized by XRD, SEM, TEM, FT-IR/FIR, UV-Vis DRS, N2 adsorption- desorption and XPS measurements. Photocatalytic degradation of Reactive Brilliant Red X-3B (RBR X-3B) was measured to evaluate the activity of the composite. Results: Sm2Ti2O7 is in the pyrochlore phase after loading on the surface of HZSM-5 zeolite. The crystal cell of pyrochlore Sm2Ti2O7 continuously expanses with decreasing Sm2Ti2O7 loading content in the composite. Bandgap energy of Sm2Ti2O7 is enlarged after supporting. The specific surface area of Sm2Ti2O7 was enlarged from 9.8 m2/g to 93 m2/g after loading. Both of the adsorption capacity and photocatalytic activity of the χSm2Ti2O7/HZSM-5 are greater than those of pure Sm2Ti2O7. After 120 min of irradiation, 73.1% of the initial RBR X-3B molecules are decomposed on 70%Sm2Ti2O7/HZSM-5, and only 27.7% of the dye is decomposed on the bare Sm2Ti2O7. Conclusion: Sm2Ti2O7 crystal growth is constrained after loading due to dispersion of Sm2Ti2O7 on the surface of HZSM-5. The specific surface area of Sm2Ti2O7 is significantly enlarged after loading. All the supported samples have greatly enhanced photocatalytic activity as compared to the bare Sm2Ti2O7.

scholarly journals Synthesis and Characterization of Uniform Spherical Nanoporous TiO2Aerogel Templated by Cellulose Alcohol-Gel with Enhanced Photocatalytic Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Zhiming Liu ◽  
Peng Wu ◽  
Shaoli Yang ◽  
Haiying Wang ◽  
Chunde Jin
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermal Method ◽  
X Ray ◽  
Double Beam ◽  
Methyl Orange Dye

The spherical nanoporous TiO2aerogels were prepared by a simple ethanol-thermal method, using spherical cellulose alcohol-gel as the template. The morphology, crystalline structure, pore size, specific surface area, and the photocatalytic activity of obtained TiO2aerogel were separately characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2adsorption-desorption isotherms, and double beam UV-VIS spectrophotometer. The characteristics of TiO2aerogels presented uniform sphere shape, good internal structural morphology, high specific surface area (ranging from 111.88 to 149.95 m2/g), and good crystalline anatase phase. Moreover, methyl orange dye was used as the target pollutant to characterize the photocatalytic activities and the adsorption performance. The photocatalytic experiment shows that the obtained spherical TiO2aerogels had a higher degradation ratio of 92.9% on methyl orange dye compared with aspherical TiO2aerogels prepared from other concentrations of tetrabutyl orthotitanate (TBOT).

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