Hollow anatase TiO2 nanoparticles with excellent catalytic activity for dichloromethane combustion

RSC Advances ◽  
2016 ◽  
Vol 6 (66) ◽  
pp. 61610-61614 ◽  
Author(s):  
Haifeng Huang ◽  
Xixiong Zhang ◽  
Xiaojia Jiang ◽  
Kang Dou ◽  
Zhiyi Ni ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Tio2 Nanoparticles ◽  
Hydrothermal Method ◽  
Anatase Tio2 ◽  
High Catalytic Activity

Hollow anatase TiO2 nanoparticles around 11.4 nm in size were prepared by a CTAB-assisted hydrothermal method. The catalyst showed high catalytic activity for dichloromethane (DCM) combustion with 90% DCM conversion at 201 °C.

Efficient visible-light-induced hydrogen evolution from water splitting using a nanocrystalline nickel phosphide catalyst

RSC Advances ◽  
2016 ◽  
Vol 6 (29) ◽  
pp. 24361-24365 ◽  
Author(s):  
Weiming Wu ◽  
Xianyang Yue ◽  
Xiao-Yuan Wu ◽  
Can-Zhong Lu
Keyword(s):  
Catalytic Activity ◽  
Visible Light ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Good Stability ◽  
High Catalytic Activity ◽  
Nickel Phosphide

Nanocrystalline Ni12P5 was synthesized by a simple hydrothermal method. It showed high catalytic activity (10 760 μmol h−1 g−1, TOF = 9.3 h−1) and good stability (15 h) for the hydrogen evolution from water under visible light irradiation.

scholarly journals Obtenção de catalisador nanoestruturado utilizando óxido de ferro suportado em resíduo de cerâmica vermelha

2019 ◽  
Vol 40 ◽  
pp. 94
Author(s):  
Fabiele Schaefer Rodrigues ◽  
Marcela Trojahn Nunes ◽  
Jocenir Boita
Keyword(s):  
Catalytic Activity ◽  
Iron Oxide ◽  
Hydrothermal Method ◽  
Scientific Community ◽  
National Laboratory ◽  
High Catalytic Activity ◽  
Nanostructured Catalyst ◽  
Synchrotron Light ◽  
Object Of Study ◽  
Technological Interest

The use of nanoparticles in the field of catalysis has been the object of study by the scientific community, due to the high catalytic activity that the nanoparticles have in front of some reactions of technological interest. The objective of this work is to obtain a nanostructured catalyst using iron oxide supported on red ceramic residue (RCV), through nanostructures synthesized by the hydrothermal method, measured through the absorption of lightning in the XANES region through the National Laboratory of Synchrotron Light LNLS).

scholarly journals Picosecond Lifetime Hot Electrons in TiO2 Nanoparticles for High Catalytic Activity

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 916
Author(s):  
Bochao Li ◽  
Hao Li ◽  
Chang Yang ◽  
Boyu Ji ◽  
Jingquan Lin ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Tio2 Nanoparticles ◽  
Second Harmonic ◽  
High Energy ◽  
High Catalytic Activity ◽  
Pump Probe ◽  
Decay Component ◽  
High Energy Electrons ◽  
Fundamental Laser ◽  
Photoemission Electron

A large number of studies have examined the origins of high-catalytic activities of nanoparticles, but very few have discussed the lifetime of high-energy electrons in nanoparticles. The lifetime is one of the factors determining electron transfer and thus catalytic activity. Much of the lifetime of electrons reported in the literature is too short for a high transfer-efficiency of photo-excited electrons from a catalyst to the attached molecules. We observed TiO2 nanoparticles using the femtosecond laser two-color pump-probe technique with photoemission electron microscopy having a 40 nm spatial resolution. A lifetime longer than 4 ps was observed together with a fast decay component of 100 fs time constant when excited by a 760 nm laser. The slow decay component was observed only when the electrons in an intermediate state pumped by the fundamental laser pulse were excited by the second harmonic pulse. The electronic structure for the asymmetry of the pump-probe signal and the origin of the two decay components are discussed based on the color center model of the oxygen vacancy.

Effects of Diameters on the Catalytic Activity of Spherical V-MCM-41 in the Selective Oxidation of Styrene

2012 ◽  
Vol 549 ◽  
pp. 137-140
Author(s):  
Yu Chen ◽  
Hua Qin ◽  
Xiao Bo Shi ◽  
Yan Kong
Keyword(s):  
Catalytic Activity ◽  
Hydrothermal Method ◽  
Selective Oxidation ◽  
Heterogeneous Catalysts ◽  
Molar Ratio ◽  
High Catalytic Activity ◽  
Precise Control ◽  
Mcm 41

Spherical V-MCM-41s with different diameter are synthesized by direct hydrothermal method through the precise control over the molar ratio of NaOH/TEOS. Vanadium supported on spherical MCM-41s is also prepared by impregnation methods. They are used as heterogeneous catalysts for the oxidation of styrene with H2O2 as oxidant. The results suggest that all catalysts have high catalytic activity, which increases with their diameter decreasing.

Anatase TiO2 nanoparticles with controllable crystallinity as a substrate for SERS: improved charge-transfer contribution

RSC Advances ◽  
2015 ◽  
Vol 5 (98) ◽  
pp. 80269-80275 ◽  
Author(s):  
Mengdi Gong ◽  
Xin Jiang ◽  
Juan Du ◽  
Xiuling Li ◽  
Xiaoxia Han ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Tio2 Nanoparticles ◽  
Hydrothermal Method ◽  
Anatase Tio2

Anatase TiO2 nanoparticles were controllably synthesized by a very simple sol-hydrothermal method with the assistance of H2SO4 for improving their SERS performances.

COBALT OXIDE DECORATED FLOWER-LIKE g-C3N4 HYBRID NANOMATERIALS FOR CARBON MONOXIDE OXIDATION

2016 ◽  
Vol 24 (05) ◽  
pp. 1750058 ◽  
Author(s):  
YAN WANG ◽  
JING HUANG ◽  
JIANLIANG CAO ◽  
GAOJIE LI ◽  
ZHANYING ZHANG
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Hydrothermal Method ◽  
Cobalt Oxide ◽  
Reaction Temperature ◽  
High Catalytic Activity ◽  
Total Conversion ◽  
Ft Ir ◽  
Excellent Stability

Co3O4 decorated flower-like g-C3N4 hybrid nanocatalysts were successfully synthesized and prepared via a facial hydrothermal method. The composition and morphology of the as-synthesized Co3O4/g-C3N4 nanocatalysts were characterized by the techniques of XRD, FT-IR, SEM, TEM, XPS and N2-sorption. The analysis results indicated that the as-synthesized samples possess the flower-like structure, which consisted of g-C3N4 nanosheets and Co3O4 nanoparticles with the size about 25[Formula: see text]nm. The as-prepared Co3O4/g-C3N4 catalysts possess high catalytic activity and excellent stability for carbon monoxide (CO) oxidation. The total conversion of Co can be kept for more than 48[Formula: see text]h under the reaction temperature of 120[Formula: see text]C.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

Ordered Intermetallic Nanoparticles with High Catalytic Activity Prepared by an Electrochemically Induced Phase Transformation

2019 ◽  
Author(s):  
Du Sun ◽  
yunfei wang ◽  
Kenneth Livi ◽  
chuhong wang ◽  
ruichun luo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffusion Mechanism ◽  
Reduction Reaction ◽  
Atomic Scale ◽  
High Catalytic Activity ◽  
Ambient Conditions ◽  
Magnetic Devices ◽  
Disordered Alloys ◽  
Ordered Intermetallic ◽  
Intermetallic Nanoparticles

<div> <p>The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi<sub>2</sub> to ordered intermetallic Pd<sub>3</sub>Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi<sub>2</sub> corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd<sub>3</sub>Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions.</p> </div>

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

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