Hydrothermal synthesis of octahedra-based layered niobium oxide and its catalytic activity as a solid acid

2014 ◽  
Vol 4 (12) ◽  
pp. 4250-4257 ◽  
Author(s):  
Toru Murayama ◽  
Junli Chen ◽  
Jun Hirata ◽  
Keeko Matsumoto ◽  
Wataru Ueda

Layered-structure-type niobium oxides were synthesized by the hydrothermal method by using ammonium niobium oxalate as a precursor.

2003 ◽  
Vol 68 (10) ◽  
pp. 1914-1926 ◽  
Author(s):  
Marcelo Boveri ◽  
Javier Agúndez ◽  
Isabel Díaz ◽  
Joaquín Pérez-Pariente ◽  
Enrique Sastre

Solid acid catalysts based on -SO3H-grafted MCM-41 mesoporous silica were prepared as catalysts for the synthesis of biodegradable surfactants leading reactions. The influence of hydrothermal synthesis time on properties of the mesoporous matrix and catalytic activity and selectivity of the catalysts in the stearic acid-glycerol esterification were studied.


RSC Advances ◽  
2016 ◽  
Vol 6 (19) ◽  
pp. 15745-15752 ◽  
Author(s):  
Yi Chen ◽  
Jianzhang Fang ◽  
Shaoyou Lu ◽  
Chaoping Cen ◽  
Cong Cheng ◽  
...  

(Ba, Mg)-codoped Bi12GeO20 was successfully synthesized through the one-step hydrothermal method, and the band gap was greatly narrowed.


2019 ◽  
Vol 43 (17) ◽  
pp. 6794-6805 ◽  
Author(s):  
Yendrapati Taraka Prabhu ◽  
V. Navakoteswara Rao ◽  
Muthukonda Venkatakrishnan Shankar ◽  
Bojja Sreedhar ◽  
Ujjwal Pal

CuO@ZnO nanostructures prepared via a modified hydrothermal method exhibited superior catalytic activity in the removal of organic pollutants and more efficient H2 production.


1992 ◽  
Vol 57 (11) ◽  
pp. 2241-2247 ◽  
Author(s):  
Tomáš Hochmann ◽  
Karel Setínek

Solid acid catalysts with acid strength of -14.52 < H0 < -8.2 were prepared by sulfate treatment of the samples of boehmite calcined at 105-800 °C. Two preparation methods were used: impregnation of the calcined boehmite with 3.5 M H2SO4 or mixing of the boehmite samples with anhydrous aluminum sulfate, in both cases followed by calcination in nitrogen at 650 °C. The catalysts were characterized by measurements of surface area, adsorption of pyridine and benzene, acid strength measurements by the indicator method and by catalytic activity tests in the isomerization of cyclohexene, p-xylene and n-hexane. Properties of the catalysts prepared by both methods were comparable.


2021 ◽  
Author(s):  
Han Gao ◽  
Xianwei Zeng ◽  
Qiang Guo ◽  
Zhi Yang ◽  
Yanwen Deng ◽  
...  

Ca doped CuScO2 (CSO) delafossite oxides with 3-4 μm were synthesized through hydrothermal method using Cu(NO3)2•3H2O, Sc(NO3)3•xH2O as precursor at 240 °C for 24 h in this work. The influence...


Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1040 ◽  
Author(s):  
Getachew Solomon ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Isabella Concina ◽  
Alberto Vomiero

Molybdenum sulfide (MoS2) has emerged as a promising catalyst for hydrogen evolution applications. The synthesis method mainly employed is a conventional hydrothermal method. This method requires a longer time compared to other methods such as microwave synthesis methods. There is a lack of comparison of the two synthesis methods in terms of crystal morphology and its electrochemical activities. In this work, MoS2 nanosheets are synthesized using both hydrothermal (HT-MoS2) and advanced microwave methods (MW-MoS2), their crystal morphology, and catalytical efficiency towards hydrogen evolution reaction (HER) were compared. MoS2 nanosheet is obtained using microwave-assisted synthesis in a very short time (30 min) compared to the 24 h hydrothermal synthesis method. Both methods produce thin and aggregated nanosheets. However, the nanosheets synthesized by the microwave method have a less crumpled structure and smoother edges compared to the hydrothermal method. The as-prepared nanosheets are tested and used as a catalyst for hydrogen evolution results in nearly similar electrocatalytic performance. Experimental results showed that: HT-MoS2 displays a current density of 10 mA/cm2 at overpotential (−280 mV) compared to MW-MoS2 which requires −320 mV to produce a similar current density, suggesting that the HT-MoS2 more active towards hydrogen evolutions reaction.


RSC Advances ◽  
2015 ◽  
Vol 5 (44) ◽  
pp. 34761-34768 ◽  
Author(s):  
B. Nageswara Rao ◽  
P. Ramesh Kumar ◽  
O. Padmaraj ◽  
M. Venkateswarlu ◽  
N. Satyanarayana

Porous α-Fe2O3 nanostructures were developed in the presence of a base catalyst by a rapid microwave assisted hydrothermal method.


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