Low-temperature route to nanoscale P3N5 hollow spheres

2003 ◽  
Vol 18 (10) ◽  
pp. 2359-2363 ◽  
Author(s):  
Hongzhou Gu ◽  
Yunle Gu ◽  
Zhefeng Li ◽  
Yongcheng Ying ◽  
Yitai Qian
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hollow Spheres ◽  
Molar Ratio ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Influence Of Temperature On ◽  
Wide Gap ◽  
20 Nm ◽  
High Degree

Nanoscale hollow spheres of amorphous phosphorus nitride (P3N5) were synthesized by reacting PCl3 with NaN3 at 150–250 °C. Transmission electron microscope images show that the hollow spheres have a diameter of 150–350 nm, and the thickness of the shell is 20 nm. A very small amount of curly films were also found in the sample prepared at 150 °C. The infrared spectrum indicates a high degree of purity. X-ray photoelectron spectroscopy indicates the presence of P and N, with a molar ratio of 1:1.62 for P:N. Ultraviolet-visible absorption spectroscopy shows an absorption band at 265–315 nm. Under photoluminescent excitation at 230 nm, the P3N5 emits ultraviolet light at 305 nm. With a band gap of 4.28 eV, the products may be a wide gap semiconductor. A possible mechanism and the influence of temperature on the formation of the hollow spheres are also discussed.

scholarly journals Heterogeneous Fenton-like oxidation of p-hydroxybenzoic acid using Fe/CeO2-TiO2 catalyst

2019 ◽  
Vol 79 (7) ◽  
pp. 1276-1286 ◽  
Author(s):  
Tijani Hammedi ◽  
Mohamed Triki ◽  
Mayra G. Alvarez ◽  
Jordi Llorca ◽  
Abdelhamid Ghorbel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Molar Ratio ◽  
Hydroxybenzoic Acid ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Temperature Programmed

Abstract This paper is built on the Fenton-like oxidation of p-hydroxybenzoic acid (p–HBZ) in the presence of H2O2 and 3%Fe supported on CeO2-TiO2 aerogels under mild conditions. These catalysts were deeply characterized by X-ray diffraction (XRD), hydrogen temperature programmed reduction (H2-TPR), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS). The effect of thermal treatment, pH (2–3, 5, 7), H2O2/p–HBZ molar ratio (5, 15, 20, 25) and reaction temperature (25 °C, 40 °C and 60 °C) on the catalytic properties of supported Fe catalysts are studied. Our results highlight the role of CeO2 and the calcination of the catalyst to obtain the highest catalytic properties after 10 min: 73% of p–HBZ conversion and 52% of total organic carbon (TOC) abatement.

scholarly journals Preparation of Fe-DopedTiO2Nanotubes and Their Photocatalytic Activities under Visible Light

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang
Keyword(s):  
Visible Light ◽  
Visible Region ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Ultrasonic Assisted ◽  
Uv Visible

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.

scholarly journals Synthesis and Characterization of Heterostructure Pd/Bi2WO6 Nanocomposites with Enhanced Properties of Visible-Light-Driven Photocatalyst

2021 ◽  
Author(s):  
Anukorn Phuruangrat ◽  
Jarupat Teppetcharat ◽  
Panudda Patiphatpanya ◽  
Phattranit Dumrongrojthanath ◽  
Somchai Thongtem ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Pd Nanoparticles ◽  
Cubic Phase ◽  
Xenon Lamp ◽  
Visible Absorption ◽  
X Ray ◽  
Visible Light Driven ◽  
20 Nm

Abstract Heterostructure Pd/Bi2WO6 nanocomposites were successful synthesized in ethylene glycol by microwave-assisted deposition method at 300 W for 10 min. Effect of the loaded Pd on phase, composition, morphology and visible-light-driven photocatalytic properties of Bi2WO6 was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fast-Fourier-Transform (FFT) diffraction, UV-visible absorption and X-ray photoelectron spectroscopy (XPS). In this research, good distribution of cubic phase of spherical Pd nanoparticles with particle size of 15–20 nm supported on orthorhombic Bi2WO6 thin nanoplates. The 10% Pd/Bi2WO6 nanocomposites reveal major metallic Pd0 species containing in Bi2WO6 sample. Microwave can be used to synthesize metallic Pd nanoparticles supporting on top of Bi2WO6 nanoplates. Photocatalytic activities of Bi2WO6 loaded with different weight contents of Pd were monitored through photodegradation of cationic rhodamine B (RhB) dye under visible light irradiation of a xenon lamp. The 10% Pd/Bi2WO6 nanocomposites have the highest photocatalytic activity because Pd nanoparticles as electron acceptors promote interfacial charge-transfer through Pd/Bi2WO6 heterojunction.

Synthesis and characterization of pure and nanosized hydroxyapatite bioceramics

2017 ◽  
Vol 6 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Aneela Anwar ◽  
Qudsia Kanwal ◽  
Samina Akbar ◽  
Aisha Munawar ◽  
Arjumand Durrani ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Calcium Nitrate ◽  
Temperature Stability ◽  
Molar Ratio ◽  
Calcium Nitrate Tetrahydrate ◽  
High Temperature Stability ◽  
X Ray ◽  
Transmission Electron ◽  
Nanosized Hydroxyapatite ◽  
Co Precipitation

AbstractSynthetic nanosized hydroxyapatite (HA) particles (<120 nm) were prepared using a co-precipitation technique by adopting two different routes – one from an aqueous solution of calcium nitrate tetrahydrate and diammonium hydrogen phosphate at pH 10 and the other by using calcium hydroxide and phosphoric acid as precursors at pH 8.5 and reaction temperature of 50°C. The lattice parameters of HA nanopowder were analogous to reference [Joint Committee on Powdered Diffraction Standards (JCPDS)] pattern no. 09-432. No decomposition of HA into other phases was observed even after heating at 1000°C in air for 1 h. This observation revealed the high-temperature stability of the HA nanopowder obtained using co-precipitation route. The effects of preliminary Ca/P molar ratio, precipitation, pH and temperature on the evolution of phase and crystallinity of the nanopowder were systematically examined and optimized. The product was evaluated by techniques such as X-ray-diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and Raman spectroscopy analyses. The chemical structural analysis of the as-prepared HA sample was performed using X-ray photoelectron spectroscopy (XPS). After heat treatment at 1000°C for 1 h and ageing for 15 h, the product was obtained as a phase-pure, highly crystalline HA nanorods.

scholarly journals Catalytic Activity of Mixed Al2O3-ZrO2 Oxides for Glucose Conversion into 5-Hydroxymethylfurfural

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 878 ◽  
Author(s):  
Benjamín Torres-Olea ◽  
Sandra Mérida-Morales ◽  
Cristina García-Sancho ◽  
Juan Antonio Cecilia ◽  
Pedro Maireles-Torres
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Molar Ratio ◽  
X Ray ◽  
Zirconium Oxides ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Secondary Reactions ◽  
Temperature Programmed ◽  
Adsorption Desorption

In the present work, a series of catalysts based on aluminum and zirconium oxides was studied for the transformation of glucose into 5-hydroxymethylfurfural. These catalysts were characterized by using experimental techniques, such as X-ray diffraction, N2 adsorption–desorption at −196 °C, X-ray photoelectron spectroscopy, temperature-programmed desorption of NH3 and CO2, and scanning transmission electron microscopy. The catalytic behavior in glucose dehydration was evaluated in a water-methyl isobutyl ketone biphasic system, in the presence of CaCl2, in order to minimize losses due to unwanted secondary reactions. High glucose conversion and 5-hydroxymethylfurfural (HMF) yield values were obtained in the presence of an Al(Zr)Ox catalyst with an Al:Zr molar ratio of 7:3, reaching 97% and 47%, respectively, at 150 °C after 120 min. Under tested conditions, this catalyst retained most of its catalytic activity for four reuses.

scholarly journals Synthesis and Characterization of B/NaF and Silicon Phthalocyanine-Modified TiO2 and an Evaluation of Their Photocatalytic Removal of Carbamazepine

Separations ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 71
Author(s):  
Chukwuka B. Anucha ◽  
IIknur Altin ◽  
Debora Fabbri ◽  
Ismail Degirmencioglu ◽  
Paola Calza ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Total Pore Volume ◽  
Pure Tio2 ◽  
Complete Disappearance ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Bet Analysis ◽  
Silicon Based ◽  
Adsorption Desorption

This study investigated the synthesis of two different types of photocatalysts, namely, boron/sodium fluoride co-doped titanium dioxide (B/NaF-TiO2), and its analogue, a dye-sensitized form of silicon-based axial methoxy substituted phthalocyanine (B/NaF-TiO2SiPc). Structural and morphological characterizations were performed via X-ray diffraction (XRD); Fourier transform infra-red (FTIR); N2 adsorption–desorption at 77 K by Brunauer–Emmett–Teller (BET) and Barrett, Joyner, and Halenda (BJH) methods; transmission electron microscopy (TEM); X-ray photoelectron spectroscopy (XPS); and UV–visible absorption spectroscopy. The estimated crystallite size of pure TiO2 and pure B/NaF-TiO2 was 24 nm, and that of B/NaF-TiO2SiPc was 29 nm, whereas particle sizes determined by TEM were 25, 28, and 31 nm for pure TiO2, B/NaF-TiO2 and B/NaF-TiO2SiPc respectively. No significant differences between B/NaF-TiO2 and B/NaF-TiO2SiPc were observed for surface area by (BET) analysis (13 m2/g) or total pore volume by the BJH application model (0.05 cm3/g). Energy band gap values obtained for B/NaF-TiO2 and B/NaF-TiO2SiPc were 3.10 and 2.90 eV respectively, lower than pure TiO2 (3.17 eV). The photocatalytic activity of the synthesized materials was tested using carbamazepine (CBZ) as the model substrate. Carbamazepine removal after 4 h of irradiation was almost 100% for B/NaF-TiO2 and 70% for B/NaF-TiO2SiPc; however, the substrate mineralization proceeded slower, suggesting the presence of organic intermediates after the complete disappearance of the pollutant.

Morphology Controllable Preparation of Gold Nanoplates through an Eco-Friendly Wet-Chemical Route

2014 ◽  
Vol 887-888 ◽  
pp. 108-111
Author(s):  
Zao Yi ◽  
Jiang Shan Luo ◽  
Xi Bo Li ◽  
Yong Yi ◽  
Xi Bin Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Molar Ratio ◽  
Chemical Route ◽  
X Ray ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Wet Chemical Route ◽  
Controllable Preparation

In this paper a simple eco-friendly wet-chemical way was mentioned to synthesize gold nanoplates. The prepared of the gold nanoplates was a seedless process that carried out by mixing HAuCl4 aqueous solution and Tannic acid (TA) solution at room temperature without the other surfactant and capping agents. The scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) have been used to characterize the shape and composition the prepared gold nanoplates. The molar ratio of HAuCl4 and TA can control the shape and the size of gold nanoplates effectively. This research can provide a simple and eco-friendly way for the prepared gold nanoplates in aqueous solution.

scholarly journals Hydrothermal synthesis of monocopper sulfide for hydrogen peroxide-assisted photodegradation of paraquat

2020 ◽  
Vol 26 (1) ◽  
Author(s):  
Rattabal Khunphonoi ◽  
Kitirote Wantala ◽  
Nurak Grisdanurak
Keyword(s):  
Photoelectron Spectroscopy ◽  
Reaction Rate ◽  
Ageing Time ◽  
Reaction Rate Constant ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Energy Band Gap ◽  
X Ray ◽  
Synthesis Parameters ◽  
Transmission Electron

Copper sulfide was prepared by a hydrothermal method at 130°C. The copper to sulfur molar ratio (6-10) and ageing time (24-72 h) were their synthesis parameters. The obtained materials were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscope (TEM), UV-DR spectroscopy and X-ray photoelectron spectroscopy (XPS). In order to obtain monocopper sulfide, CuS, named as covellite, the molar recipe ratio of sulfur to copper should be less than 8 in any hydrothermal ageing time. The morphology showed spherical-like structure with energy band gap of 1.88-2.04 eV. CuS was tested for its photocatalytic degradation of paraquat under visible light irradiation. It exhibited excellent activities in the presence of H<sub>2</sub>O<sub>2</sub>. The kinetic of paraquat degradation was also investigated using Langmuir-Hinshelwood-Hougen-Watson (LHHW) model. The reaction rate constant was three times higher than TiO<sub>2</sub> under the same studied conditions.

Synthesis and Optical Properties of L-Cysteine Hydrochloride-Stabilized CdSe Nanocrystals in a New Alkali System

2008 ◽  
Vol 8 (3) ◽  
pp. 1178-1182 ◽  
Author(s):  
Bin Feng ◽  
Feng Teng ◽  
Ai-Wei Tang ◽  
Yan Wang ◽  
Yan-Bing Hou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Water Soluble ◽  
Molar Ratio ◽  
Cdse Nanocrystals ◽  
X Ray ◽  
Transmission Electron ◽  
Cysteine Hydrochloride

Water-soluble CdSe nanocrystals were synthesized in a new alkali system at lower temperatures by using L-cysteine hydrochloride as a stabilizer and Na2SeSO3 as a selenium source to enable the synthesis of CdSe nanocrystals in a wider range of pHvalues. The CdSe nanocrystal powder was characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy. We systematically investigated the effect of synthesis conditions on the optical properties of the L-cysteine hydrochloride-stabilized CdSe nanocrystals, and found that different sizes of CdSe nanocrystals can be obtained by changing the pHvalue, the molar ratio of L-cysteine hydrochloride to Cd2+, or the refluxing time. The emission maxima of the obtained CdSe nanocrystals can be tuned in a wider range from 477 to 575 nm by changing the pHvalue from 7 to 13. We observed an obvious blue-shift of the absorption and photoluminescence peak position by varying the molar ratio of L-Cys to Cd2+ from 3.5:1 to 2:1 at the same pHvalue. The size of the obtained nanocrystals increased and the full width at half maximum became narrower as reflux time increased. Transmission electron microscopy images indicate that the as-prepared CdSe nanocrystals have a good dispersion, which means that L-cysteine hydrochloride can control the grouping of CdSe nanocrystals excellently as a stabilizer in the new alkali system.

One-Pot Synthesis of Nanodendritic PtIr Alloy with High Electrochemical Activity for Ethylene Glycol Oxidation

NANO ◽  
2017 ◽  
Vol 12 (02) ◽  
pp. 1750026 ◽  
Author(s):  
Xuedong Gao ◽  
Lulu Liu ◽  
Qiyu Wang ◽  
Kun Qi ◽  
Zhao Jin ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Photoelectron Spectroscopy ◽  
Three Dimensional ◽  
One Pot ◽  
X Ray ◽  
Electrochemical Tests ◽  
Transmission Electron ◽  
Ethylene Glycol Oxidation ◽  
Networks Structure ◽  
20 Nm

Nanodendritic Pt-based bimetallic alloys are one promising catalyst with three-dimensional (3D) networks structure composed of integrating branches for electrochemical catalytic reaction. We successfully synthesized dendrites Pt6Ir4 alloy with small size of 20 nm in oleylamine. The dendritic Pt6Ir4 alloy are characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical tests suggest that the as-prepared dendritic Pt6Ir4 alloy exhibits greatly enhanced ethylene glycol oxidation reaction (EGOR) activity than commercial Pt/C with high EGOR mass activity, anti-poisoning and stability.

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