scholarly journals Local Structure and Redox Properties of Amorphous CeO2-TiO2 Prepared Using the H2O2-Modified Sol-Gel Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2148
Author(s):  
Myungju Kim ◽  
Gwanhee Park ◽  
Heesoo Lee
Keyword(s):  
Oxygen Reduction ◽  
Local Structure ◽  
Sol Gel ◽  
Temperature Shift ◽  
Redox Properties ◽  
Reduction Peak ◽  
Gel Method ◽  
Sol Gel Method ◽  
Peak Broadening ◽  
The Difference

Amorphous CeO2-TiO2 nanoparticles synthesized by the H2O2-modified sol-gel method were investigated in terms of the Ce-O-Ce and Ti-O-Ti linkage, local structure, and redox properties. The decrease in the crystallinity of CeO2-TiO2 by H2O2 addition was confirmed. The metal–oxygen linkage analysis showed the difference in size of the metal–oxygen network between crystalline CeO2-TiO2 and amorphous CeO2-TiO2 due to the O22− formed by H2O2. The local structure of CeO2-TiO2 was analyzed with an extended X-ray absorption fine structure (EXAFS), and the oscillation changes in the k space revealed the disordering of CeO2-TiO2. The decrease in Ce-O bond length and the Ce-O peak broadening was attributed to O22− interfering with the formation of the extended metal–oxygen network. The temperature-programmed reduction of the H2 profile of amorphous CeO2-TiO2 exhibited the disappearance of the bulk oxygen reduction peak and a low-temperature shift of the surface oxygen reduction peak. The H2 consumption increased compared to crystalline CeO2-TiO2, which indicated the improvement of redox properties by amorphization.

scholarly journals Phosphoric acid adsorbed on silica-ceria matrix obtained by sol-gel method: studies of local structure, texture and acid property

2007 ◽  
Vol 18 (5) ◽  
pp. 976-983 ◽  
Author(s):  
Fábio L. Pissetti ◽  
Maria Suzana P. Francisco ◽  
Richard Landers ◽  
Yoshitaka Gushikem
Keyword(s):  
Phosphoric Acid ◽  
Local Structure ◽  
Sol Gel ◽  
Acid Property ◽  
Gel Method ◽  
Sol Gel Method

scholarly journals In-situ investigations of the photoluminescence properties ofSiO2/TiO2binary and Boron-SiO2/TiO2ternary oxides prepared by the sol-gel method and their photocatalytic reactivity for the oxidative decomposition of trichloroethylene

2003 ◽  
Vol 5 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Kyeong Youl Jung ◽  
Seung Bin Park ◽  
Masaya Matsuoka ◽  
Masakazu Anpo
Keyword(s):  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Quenching Efficiency ◽  
Ft Ir ◽  
The Difference ◽  
Relationship Of ◽  
The Relationship ◽  
Photoluminescence Behavior

Photoluminescence behavior ofTiO2,SiO2/TiO2binary and Boron-SiO2/TiO2ternary oxides prepared by the sol-gel method was investigated. The differences in their photocatalytic reactivities ofTiO2-based photocatalysts were interpreted in terms of the relationship of the difference in their photoluminescence characteristics. The addition ofSiO2intoTiO2matrix induced new photoluminescence sites, which were due to anchored titanium oxide species (i.e., the formation of Ti–O–Si bonds) located on the surface. The photoluminescence was found to be very sensitive to the presence of oxygen. These new photoluminescence completely disappeared by the addition of boron intoSiO2/TiO2binary oxide, since the emitting sites having a Ti–O–Si bond were destroyed and the new sites having B–O–Ti or Si–O–B bonds were constructed on the surface, being in agreement with the results obtained by FT-IR measurements. For allTiO2-based photocatalysts, a significant quenching of photoluminescence was observed by the addition of oxygen. It was found that the photocatalytic reactivity ofTiO2-based photocatalysts for the decomposition of trichloroethylene was clearly associated with their relative quenching efficiencies of photoluminescence; photocatalyst showing high quenching efficiency exhibited a high photocatalytic reactivity.

An EXAFS study of the local structure around Zr atoms in Y2O3-stabilized ZrO2 by the sol-gel method

1994 ◽  
Vol 177 ◽  
pp. 179-186 ◽  
Author(s):  
Gianni Antonioli ◽  
Pier Paolo Lottici ◽  
Ivano Manzini ◽  
Guglielmina Gnappi ◽  
Angelo Montenero ◽  
...  
Keyword(s):  
Local Structure ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Exafs Study

The local structure of Sm-doped aluminosilicate glasses prepared by sol–gel method

2000 ◽  
Vol 262 (1-3) ◽  
pp. 183-190 ◽  
Author(s):  
Jisun Jin ◽  
Shinichi Sakida ◽  
Toshinobu Yoko ◽  
Masayuki Nogami
Keyword(s):  
Local Structure ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Aluminosilicate Glasses

Visible light activated photo-catalytic effect and local structure of iron silicate glass prepared by sol-gel method

2013 ◽  
Vol 226 (1-3) ◽  
pp. 747-753 ◽  
Author(s):  
Yusuke Takahashi ◽  
Shiro Kubuki ◽  
Kazuhiko Akiyama ◽  
Katalin Sinkó ◽  
Ernő Kuzmann ◽  
...  
Keyword(s):  
Visible Light ◽  
Silicate Glass ◽  
Local Structure ◽  
Catalytic Effect ◽  
Sol Gel ◽  
Iron Silicate ◽  
Gel Method ◽  
Sol Gel Method ◽  
Iron Silicate Glass

scholarly journals Oxygen Reduction Reaction (ORR) on a Mixed Titanium and Tantalum Oxy-nitride Catalyst Prepared by the Urea-based Sol-gel Method

2014 ◽  
Vol 17 (2) ◽  
pp. 055-065 ◽  
Author(s):  
A. Seifitokaldani ◽  
M. Perrier ◽  
O. Savadogo
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Sol Gel ◽  
Active Surface ◽  
Reduction Reaction ◽  
Active Surface Area ◽  
Gel Method ◽  
Sol Gel Method ◽  
Onset Potential

The electrochemical stability and activity of different compositions of titanium and tantalum oxy-nitride nano-catalysts were investigated for the oxygen reduction reaction (ORR). A new sol-gel method was used to produce a nano-powder mixture of Ti and Ta oxynitride from their alkoxides using urea as a nitrogen source. The precursors prepared by the sol-gel method were annealed in a N2 + 3% H2 atmosphere at determined temperatures (500, 700 and 900 °C) inside a silica tube furnace. X-ray diffraction results proved that by using this method a considerable amount of nitrogen was inserted into the catalyst structure at a relatively low temperature. Energy dispersive spectroscopy showed that the prepared catalyst should be oxidized carbonitride of titanium and/or tantalum. Heat treatment had a major effect on the onset potential by changing the crystallinity of the catalyst, so that the onset potential of titanium oxynitride increased from ca. 0.05 V to 0.65 V vs. NHE by increasing the temperature from 500 to 700 °C. Increasing the Ta concentration also led to a higher onset potential but lower ORR current. For instance, the onset potential for the ORR for tantalum oxynitride heat treated at 700 °C was ca. 0.85 V vs. NHE while this value was ca. 0.65 V vs. NHE for titanium oxynitride. However, the ORR current was 100 times smaller in tantalum oxynitride, most likely because of a low electrochemically active surface area. Electrochemical measurements suggested that an appropriate composition of titanium and tantalum was required to have both a good onset potential and ORR current by improving the catalytic activity and increasing the active surface area and electrical conductivity.

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