scholarly journals Low Temperature HCHO Detection by SnO2/TiO2@Au and SnO2/TiO2@Pt: Understanding by in-situ DRIFT Spectroscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2049
Author(s):  
Abulkosim Nasriddinov ◽  
Vadim Platonov ◽  
Alexey Garshev ◽  
Marina Rumyantseva
Keyword(s):  
Low Temperature ◽  
Chemical Precipitation ◽  
Surface Reactivity ◽  
Precipitation Method ◽  
Impregnation Method ◽  
Drift Spectroscopy ◽  
Au Nps ◽  
Sensor Properties ◽  
In Situ Drift

In this work we analyze the effectiveness of decoration of nanocrystalline SnO2/TiO2 composites with gold nanoparticles (Au NPs) and platinum nanoparticles (Pt NPs) in enhancing gas sensor properties in low-temperature HCHO detection. Nanocrystalline SnO2/TiO2 composites were synthesized by a chemical precipitation method with following modification with Pt and Au NPs by the impregnation method. The nanocomposites were characterized by TEM, XRD, Raman and FTIR spectroscopy, DRIFTS, XPS, TPR-H2 methods. In HCHO detection, the modification of SnO2 with TiO2 leads to a shift in the optimal temperature from 150 to 100 °C. Further modification of SnO2/TiO2 nanocomposites with Au NPs increases the sensor signal at T = 100 °C, while modification with Pt NPs gives rise to the appearance of sensor responses at T = 25 °C and 50 °C. At 200 °C nanocomposites exhibited high selectivity toward formaldehyde within the sub-ppm concentration range among different VOCs. The influence of Pt and Au NPs on surface reactivity of SnO2/TiO2 composite and enhancement of the sensor response toward HCHO was studied by DRIFT spectroscopy and explained by the chemical and electronic sensitization mechanisms.

scholarly journals Insight into the Promoting Role of Er Modification on SO2 Resistance for NH3-SCR at Low Temperature over FeMn/TiO2 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 618
Author(s):  
Huan Du ◽  
Zhitao Han ◽  
Xitian Wu ◽  
Chenglong Li ◽  
Yu Gao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalyst Surface ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Tio2 Catalyst ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
So2 Resistance ◽  
Fast Scr

Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism. DRIFTS.

Size Controllable Synthesis and Characterization of CuO Nanostructure

2018 ◽  
Vol 915 ◽  
pp. 98-103 ◽  
Author(s):  
Duygu Candemir ◽  
Filiz Boran
Keyword(s):  
Freeze Drying ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peg 4000 ◽  
Structure Morphology ◽  
Cuo Nanostructure

In this study, copper oxide (CuO) nanostructures were successfully prepared by adding EG (ethylene glycol) and PEG (4000, 8000) (polyethylene glycol) via an in-situ chemical precipitation method. EG and PEG (4000, 8000) were effective for changing the particular size of CuO and we examined the effects of drying type such as freeze drying, muffle and horizontal furnace on the size of CuO nanostructure. The structure, morphology and elemental analysis of CuO nanostructure were analyzed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Also, the CuO nanostructures showed excellent electrical conductivity by the changing of PEG’s molecular weight and drying processes.

Steam reforming of ethanol over mesoporous Rh/CeZrO2: Mechanistic evaluation using in situ DRIFT spectroscopy

2016 ◽  
Vol 94 (4) ◽  
pp. 752-760 ◽  
Author(s):  
Pankaj Kumar Sharma ◽  
Navin Saxena ◽  
Vimlesh Kumar Bind ◽  
Prasun Kumar Roy ◽  
Arti Bhatt
Keyword(s):  
Steam Reforming ◽  
Drift Spectroscopy ◽  
Steam Reforming Of Ethanol ◽  
In Situ Drift

Synthesis and Characterization of Modified Diatomite-Leaf-Like CuO Nanosheet Composites

2018 ◽  
Vol 915 ◽  
pp. 93-97
Author(s):  
Filiz Boran
Keyword(s):  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Morphology ◽  
Cuo Nanosheets ◽  
20 Nm ◽  
Modified Diatomite

In this work, firstly we described the effect of freeze drying on modification of raw diatomite. And then, modified diatomite-leaf-like copper oxide (CuO) nanosheet composite was successfully prepared by surfactant-free in-situ chemical precipitation method. The structure, morphology and elemental analysis of CuO nanosheets and its composite were analyzed by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDAX). Dimensions of leaf-like CuO nanosheets were approximately determined as 160 nm in width, 320 nm in length and 20 nm in thickness. According to the EDAX spectrum, leaf-like CuO nanosheets composed of Cu and O atoms without any impurity and also uniformly covered the entire surface of modified diatomite.

The Effects of SiO2 and CeO2 Addition on the Performances of MnOx/TiO2 Catalysts

2016 ◽  
Vol 69 (10) ◽  
pp. 1180
Author(s):  
Juhua Luo ◽  
Hongkai Mao ◽  
Xu Wang ◽  
Wei Yao
Keyword(s):  
Low Temperature ◽  
Pore Diameter ◽  
Catalytic Reduction ◽  
Pure Tio2 ◽  
Precipitation Method ◽  
Impregnation Method ◽  
Average Pore ◽  
Reduction Of No ◽  
No Conversion ◽  
Co Precipitation

A TiO2-SiO2 mixed oxide was obtained by a co-precipitation method. MnOx-CeO2/TiO2-SiO2 were prepared by an impregnation method and their activity towards the selective catalytic reduction of NO with NH3 at low temperature were evaluated. Compared with pure TiO2, TiO2-SiO2 exhibited an evidently larger surface area and pore volume, and a smaller average pore diameter with narrow distribution. The NO conversion of the MnOx/TiO2-SiO2 catalyst could be improved by the addition of an appropriate amount of CeO2 in the temperature range of 100–180°C. MnOx-CeO2/TiO2-SiO2 with 10 wt-% CeO2 showed the highest activity with 96 % NO conversion at 180°C.

HIGH PRESSURE EFFECTS ON ELECTRICAL RESISTIVITY AND DIELECTRIC PROPERTIES OF NANOCRYSTALLINE SnO2

2006 ◽  
Vol 05 (04n05) ◽  
pp. 471-477 ◽  
Author(s):  
P. THANGADURAI ◽  
A. CHANDRA BOSE ◽  
S. RAMASAMY ◽  
R. KESAVAMOORTHY ◽  
T. R. RAVINDRAN
Keyword(s):  
High Pressure ◽  
Dielectric Properties ◽  
Complex Impedance ◽  
Chemical Precipitation ◽  
Pressure Effects ◽  
Precipitation Method ◽  
Grain Sizes ◽  
Electrical And Dielectric Properties ◽  
High Pressure Effects

Rutile structured nanocrystalline tin oxide (nano- SnO 2) was prepared by chemical precipitation method with different grain sizes. Its electrical and dielectric properties were studied using complex impedance spectroscopy under different hydrostatic pressures. These studies showed a transition in nano- SnO 2 under high-pressure. The transition pressures obtained from both the resistivity and dielectric measurements agree with each other and increase considerably with decrease in grain size. In order to find whether the transition under pressure is structural related or not, in situ high pressure Raman spectroscopy was done up to 3.38 GPa at room temperature. No structural change was observed and the transition may be due to the co-operative phenomenon of the change in band gap and better connectivity between grain boundaries.

scholarly journals In situ synthesis of PANI/CuO nanocomposites for non-enzymatic electrochemical glucose sensing

2020 ◽  
Vol 3 (2) ◽  
pp. 9
Author(s):  
Gul Rahman ◽  
Mustifuz Ur Rahman ◽  
Zainab Najaf
Keyword(s):  
Copper Oxide ◽  
Copper Substrate ◽  
Chemical Precipitation ◽  
Glucose Sensing ◽  
In Situ Synthesis ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Vis Spectroscopy ◽  
Composite Formation

We report the in situ synthesis of polyaniline/copper oxide (PANI/CuO) nanocomposites and their characterization as electrocatalyst for non-enzymatic electrochemical glucose detection. Copper oxide (CuO) nanoparticles were prepared by wet chemical precipitation method followed by thermal treatment while the composites of PANI and CuO were synthesized by in situ chemical polymerization of aniline with definite amount of CuO. X-ray diffraction (XRD) results revealed that the composites are predominantly amorphous. The composite formation was confirmed by fourier transform infrared (FTIR) and UV-Vis spectroscopy analysis. The surface morphology was greatly altered with the amount of CuO in composite structure. PANI/CuO nanocomposites were coated on copper substrate to investigate their electrocatalytic activity for glucose sensing. PANI/CuO with 10 wt. % CuO exhibited good response towards electrochemical glucose oxidation.

Sign in / Sign up

Export Citation Format

Share Document