One-pot synthesis of nano titanium dioxide in supercritical water

AbstractSupercritical hydrothermal synthesis of nanosized metal oxides is of great interest for scholars due to its one-pot and readily realizing commercial production process. Hydrothermal synthesis of nanosized TiO2 in subcritical and supercritical water was investigated with different reaction temperatures (250–450°C), time (3–10 min), precursor species (Ti(SO4)2, TiCl4), and the addition of a surfactant (CH3(CH2)5NH2). TiO2 synthesized under supercritical state has a higher degree of crystallinity when compared with TiO2 obtained from subcritical state, which is attributed to a higher reaction rate. Extending reaction time from 3 to 10 min leads to the growth of crystal and broader size distribution (36.66 ± 8.5 nm). More uniform products can be obtained when Ti(SO4)2 acting as the precursor compared with TiCl4 being the precursor. The application of surfactant CH3(CH2)5NH2 in the synthesis makes chemical bonding between the particle surface and organic ligand. It affects the growth direction of TiO2 crystal; as a result, rod-like TiO2 crystal is obtained.

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Organic-ligand-assisted supercritical hydrothermal synthesis of titanium oxide nanocrystals leading to perfectly dispersed titanium oxide nanoparticle in organic phase

Journal of Nanoparticle Research ◽

10.1007/s11051-006-9186-2 ◽

2007 ◽

Vol 9 (6) ◽

pp. 1067-1071 ◽

Cited By ~ 20

Author(s):

Tahereh Mousavand ◽

Jing Zhang ◽

Satoshi Ohara ◽

Mitsuo Umetsu ◽

Takashi Naka ◽

...

Keyword(s):

Hydrothermal Synthesis ◽

Titanium Oxide ◽

Organic Phase ◽

Organic Ligand ◽

Oxide Nanoparticle ◽

Supercritical Hydrothermal Synthesis

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Supercritical hydrothermal synthesis of UO2+x: stoichiometry, crystal shape and size, and homogeneity observed using 23Na-NMR spectroscopy of (U, Na)O2+x

CrystEngComm ◽

10.1039/d1ce00996f ◽

2021 ◽

Author(s):

Chihiro Tabata ◽

Kenji Shirasaki ◽

Ayaki Sunaga ◽

Hironori Sakai ◽

Dexin Li ◽

...

Keyword(s):

Hydrothermal Synthesis ◽

Nmr Spectroscopy ◽

Supercritical Water ◽

Uranium Dioxide ◽

Nitrate Solution ◽

Starting Material ◽

Crystal Shape ◽

Supercritical Hydrothermal Synthesis ◽

23Na Nmr ◽

Shape And Size

The hydrothermal synthesis of pure uranium dioxide under supercritical water (SCW) conditions was investigated using a starting material composed of a uranyl(vi) nitrate solution at 450 °C.

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Supercritical Hydrothermal Synthesis of Ultra-Fine Copper Particles Using Different Precursors

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.744.493 ◽

2017 ◽

Vol 744 ◽

pp. 493-497 ◽

Cited By ~ 1

Author(s):

Pan Pan Sun ◽

Shu Zhong Wang ◽

Yan Hui Li ◽

Tuo Zhang

Keyword(s):

Hydrothermal Synthesis ◽

Supercritical Water ◽

Fine Particles ◽

Copper Ions ◽

Synthesis Method ◽

Reaction Times ◽

Copper Particles ◽

Supercritical Hydrothermal Synthesis ◽

Ultra Fine Particles ◽

Fine Copper

Supercritical hydrothermal synthesis is a green synthesis method for metal and metal oxide ultra-fine particles. Ultra-fine copper particles are of great interests for the researchers because of the excellent performance in recent years. In this paper, supercritical hydrothermal synthesis of copper ultra-fine particles with three different precursors (CuSO4, Cu(NO3)2, Cu(HCOO)2) are reported. This thesis reports that different products are produced with different precursors. Also, three kinds of reaction mechanisms with different precursors in supercritical water were explained. The conversion of copper ions in the reaction of Cu(HCOO)2 in supercritical water is the highest, the value reaches 100.0%. In the process of synthesizing ultra-fine copper particles, different additional HCOOH concentrations (0, 0.1 mol/L, 0.2 mol/L) and different reaction times (5 mins, 10 mins) were applied. Zero-valent ultra-fine copper particles without impurity were synthesized. The synthesized copper ultra-fine particles were cubic aggregations with micro-meter size

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One-pot hydrothermal synthesis of nitrogen-doped reduced graphene oxide for the highly sensitive and simultaneous determination of dihydroxy benzene isomers

Journal of Applied Electrochemistry ◽

10.1007/s10800-021-01563-z ◽

2021 ◽

Author(s):

Ezhilan Jayabal ◽

Aravindan Natarajan ◽

Venkatesan Rengarajan

Keyword(s):

Graphene Oxide ◽

Hydrothermal Synthesis ◽

Simultaneous Determination ◽

Reduced Graphene Oxide ◽

One Pot ◽

Nitrogen Doped ◽

Reduced Graphene ◽

Highly Sensitive

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L-cysteine and urea synergistically-mediated one-pot one-step self-transformed hydrothermal synthesis of p-Ag2S/n-AgInS2 core-shell heteronanoflowers for photocatalytic MO degradation

Applied Surface Science ◽

10.1016/j.apsusc.2021.149279 ◽

2021 ◽

Vol 548 ◽

pp. 149279

Author(s):

Yunhe Li ◽

Ye Liu ◽

Ge Gao ◽

Ying Zhu ◽

Dan Wang ◽

...

Keyword(s):

Hydrothermal Synthesis ◽

Core Shell ◽

One Pot ◽

One Step

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One-pot hydrothermal synthesis: Enhanced MOR and OER performance using low-cost Mn3O4 electrocatalyst

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2020.11.147 ◽

2021 ◽

Vol 46 (27) ◽

pp. 13946-13951

Author(s):

P.C. Nagajyothi ◽

R. Ramaraghavulu ◽

K. Munirathnam ◽

K. Yoo ◽

Jaesool Shim

Keyword(s):

Hydrothermal Synthesis ◽

Low Cost ◽

One Pot

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Super Hybrid Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.700.145 ◽

2011 ◽

Vol 700 ◽

pp. 145-149 ◽

Cited By ~ 1

Author(s):

Tadafumi Adschiri ◽

S. Takami ◽

K. Minami ◽

T. Yamagata ◽

K. Miyata ◽

...

Keyword(s):

Thermal Conductivity ◽

Refractive Index ◽

Supercritical Water ◽

Metal Salt ◽

High Surface ◽

Functional Materials ◽

High Refractive Index ◽

High Thermal Conductivity ◽

Base Catalysts ◽

Supercritical Hydrothermal Synthesis

Various composite materials have been developed, but in many cases problems arise due to the combined materials such as fabrication becoming difficult because of the significant increase in viscosity, and transparency of the polymer is sacrificed. These issues can be overcome by controlling the nanointerface; however, this is considered as a difficult task since nanoparticles (NPs) easily aggregate in polymer matrices because of their high surface energy. Organic functionalization of inorganic NPs is required to increase affinity between NPs and polymers. For fabricating multi-functional materials, we proposed a new method to synthesize organic modified NPs by using supercritical water. Because organic molecules and metal salt aqueous solutions are miscible in supercritical water and water molecules serve as acid/base catalysts for the reactions, hybrid organic/inorganic NPs can be synthesized under the supercritical condition. The hybrid NPs show high affinity for the organic solvent and the polymer matrix, which leads to the fabrication of these super hybrid NPs. How to release the heat from the devices is the bottle neck of developing the future power devices, and thus nanohybrid materials of polymer and ceramics are required to achieve both high thermal conductivity and easy thin film flexible fabrication, namely trade-off functions. Surface modification of the BN particles via supercritical hydrothermal synthesis improves the affinity between BN and the polymers. This increases the BN loading ratio in the polymers, thus resulting in high thermal conductivity. Transparent dispersion of high refractive index NPs, such as TiO2 and ZrO2, in the polymers is required to fabricate optical materials. By adjusting the affinity between NPs and the polymers, we could fabricate super hybrid nanomaterials, which have flexiblility and high refractive index and transparency.

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