A highly active K/Cu-Mn-O catalyst for the removal of nitric oxide in indoor air

2017 ◽  
Vol 28 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Chan Wang ◽  
Feng Li ◽  
Zishu Sun ◽  
Qijun Song
Keyword(s):  
Nitric Oxide ◽  
Indoor Air ◽  
Photoelectron Spectroscopy ◽  
Elimination Rate ◽  
Surface Concentration ◽  
Precipitation Method ◽  
X Ray ◽  
Highly Active ◽  
Metal Nitrates ◽  
Co Precipitation

Nitric oxide is a frequently encountered pollutant in indoor air. It could have a number of harmful effects on human health even at low concentration. Aiming to improve the indoor air quality, an environment-friendly method was developed for the elimination of nitric oxide at ppm level based on a low temperature effective catalyst potassium-doped copper–manganese oxide (K/Cu-Mn-O). The catalyst was obtained through a co-precipitation method using metal nitrates in aqueous solution and the precipitate was calcinated at 400℃ for 5 h. After impregnation with K, the best catalytic activity was observed for the K/Cu-Mn-O catalyst with a Cu/Mn ratio of 1:2 and surface concentration of doping K 7.03% (7.4 mg/g). The composition and the structure of the catalyst were comprehensively characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller. The results showed that the potassium doping improved the adsorption ability of catalyst, and promoted the formation of the nitrate salt, and thereby further improved the elimination rate of nitric oxide. Finally, the possible reaction mechanisms are discussed.

Hydroformylation of Dicyclopentadiene over Rh Catalysts Supported on Fe2O3, Co3O4 and Fe2O3–Co3O4 Mixed Oxide

2017 ◽  
Vol 42 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Yubo Ma ◽  
Zhixian Gao ◽  
Wumanjiang Eli
Keyword(s):  
Mixed Oxide ◽  
Photoelectron Spectroscopy ◽  
Supported Catalyst ◽  
Precipitation Method ◽  
X Ray ◽  
Analysis Techniques ◽  
Rh Catalyst ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Effect Of The Support

Rh catalysts supported on Fe2O3, Co3O4 and Fe2O3–Co3O4 mixed oxide were prepared by the co-precipitation method. The effect of the support on the performance of the Rh catalysts for the hydroformylation of dicyclopentadiene was investigated using X-ray photoelectron spectroscopy, H2-temperature-programmed reduction, H2-temperature-programmed desorption and Brunauer–Emmett–Teller analysis techniques. The results indicated that the Fe2O3–Co3O4 supported catalyst had a higher dispersion of Rh and thus more Rh+ sites. As a result, the Fe2O3–Co3O4 supported Rh catalyst exhibited higher activity compared with counterparts supported on Fe2O3 and Co3O4.

scholarly journals Bio-assisted preparation of efficiently architectured nanostructures of γ-Fe2O3 as a molecular recognition platform for simultaneous detection of biomarkers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sasikala Sundar ◽  
V. Ganesh
Keyword(s):  
Electron Microscopy ◽  
Iron Oxide ◽  
Photoelectron Spectroscopy ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Precipitation Method ◽  
Limit Values ◽  
X Ray ◽  
Co Precipitation ◽  
The Individual

Abstract Magnetic nanoparticles of iron oxide (γ-Fe2O3) have been prepared using bio-assisted method and their application in the field of biosensors is demonstrated. Particularly in this work, different nanostructures of γ-Fe2O3 namely nanospheres (NS), nanograsses (NG) and nanowires (NW) are prepared using a bio-surfactant namely Furostanol Saponin (FS) present in Fenugreek seeds extract through co-precipitation method by following “green” route. Three distinct morphologies of iron oxide nanostructures possessing the same crystal structure, magnetic properties, and varied size distribution are prepared and characterized. The resultant materials are analyzed using field emission scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometer and Fourier transform infrared spectroscopy. Moreover, the effect of reaction time and concentration of FS on the resultant morphologies of γ-Fe2O3 nanostructures are systematically investigated. Among different shapes, NWs and NSs of γ-Fe2O3 are found to exhibit better sensing behaviour for both the individual and simultaneous electrochemical detection of most popular biomarkers namely dopamine (DA) and uric acid (UA). Electrochemical studies reveal that γ-Fe2O3 NWs showed better sensing characteristics than γ-Fe2O3 NSs and NGs in terms of distinguishable voltammetric signals for DA and UA with enhanced oxidation current values. Differential pulse voltammetric studies exhibit linear dependence on DA and UA concentrations in the range of 0.15–75 µM and 5 μM – 0.15 mM respectively. The detection limit values for DA and UA are determined to be 150 nM and 5 µM. In addition γ-Fe2O3 NWs modified electrode showed higher sensitivity, reduced overpotential along with good selectivity towards the determination of DA and UA even in the presence of other common interferents. Thus the proposed biosensor electrode is very easy to fabricate, eco-friendly, cheaper and possesses higher surface area suggesting the unique structural patterns of γ-Fe2O3 nanostructures to be a promising candidate for electrochemical bio-sensing and biomedical applications.

scholarly journals Effect of Y Modified Ceria Support in Mono and Bimetallic Pd–Au Catalysts for Complete Benzene Oxidation

Catalysts ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 283 ◽  
Author(s):  
Lyuba Ilieva ◽  
Anna Venezia ◽  
Petya Petrova ◽  
Giuseppe Pantaleo ◽  
Leonarda Liotta ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Benzene Oxidation ◽  
Total Oxidation ◽  
Pd Catalysts ◽  
X Ray ◽  
Close Relationship ◽  
Ceria Support ◽  
Co Precipitation

Mono metallic and bimetallic Pd (1 wt. %)–Au (3 wt. %) catalysts were prepared using two ceria supports doped with 1 wt. % Y2O3. Yttrium was added by impregnation or co-precipitation. The catalyst synthesis was carried out by deposition–precipitation method, with sequential deposition–precipitation of palladium over previously loaded gold in the case of the bimetallic samples. The obtained materials, characterized by X-ray powder diffraction (XRD), High resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR) techniques, were tested in the complete benzene oxidation (CBO). The results of the characterization analyses and the catalytic performance pointed to a close relationship between structural, redox, and catalytic properties of mono and bimetallic catalysts. Among the monometallic systems, Pd catalysts were more active as compared to the corresponding Au catalysts. The bimetallic systems exhibited the best combustion activity. In particular, over Pd–Au supported on Y-impregnated ceria, 100% of benzene conversion towards total oxidation at the temperature of 150 °C was obtained. Comparison of surface sensitive XPS results of fresh and spent catalysts ascertained the redox character of the reaction.

scholarly journals Synthesis of DME by CO2 hydrogenation over La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts

2017 ◽  
Vol 23 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Yajing Zhang ◽  
Yu Zhang ◽  
Fu Ding ◽  
Kangjun Wang ◽  
Wang Xiaolei ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Direct Synthesis ◽  
Catalytic Performance ◽  
Co2 Hydrogenation ◽  
Precipitation Method ◽  
X Ray ◽  
Temperature Programmed ◽  
And Performance ◽  
Co Precipitation ◽  
Adsorption Desorption

A series of La2O3-modified CuO-ZnO-ZrO2/HZSM-5 catalysts were prepared by an oxalate co-precipitation method. The catalysts were fully characterized by X-ray diffraction (XRD), N2 adsorption-desorption, hydrogen temperature pro-grammed reduction (H2-TPR), ammonia temperature programmed desorption (NH3-TPD), and X-ray photoelectron spectroscopy (XPS) techniques. The effect of the La2O3 content on the structure and performance of the catalysts was thoroughly investigated. The catalysts were evaluated for the direct synthesis of dimethyl ether (DME) from CO2 hydrogenation. The results displayed that La2O3 addition enhanced catalytic performance, and the maximal CO2 conversion (34.3%) and DME selectivity (57.3%) were obtained over the catalyst with 1% La2O3, which due to the smaller size of Cu species and a larger ratio of Cu+/Cu.

Effect of Noble Metals on Selective Detection of LPG Based on SnO2

1996 ◽  
Vol 459 ◽  
Author(s):  
A. Ratna Phani ◽  
M. Pelino
Keyword(s):  
Photoelectron Spectroscopy ◽  
Noble Metals ◽  
Electrical Response ◽  
Base Material ◽  
High Sensitivity ◽  
Precipitation Method ◽  
X Ray ◽  
Spectroscopy Studies ◽  
Metal Doped ◽  
Co Precipitation

ABSTRACTThe present investigation deals with the electrical response of noble metal doped SnO2 to improve the selectivity for Liquid Petroleum Gas (LPG) in the presence of CO and CH4. Addition of small amounts of nobel metals (Pd, Pt and Rh) to the base material SnO2 is carried out by co-precipitation method. X-ray diffraction and X-ray photoelectron spectroscopy studies are carried out to find out the crystalline phase and chemical composition of the SnO2. The sensor element has been tested for cross selectivity to reducing gases by measuring sensitivity versus sintering temperatures and sensitivity versus operating temperatures. The sensor elements with the composition of Pd (1.5 wt%) andPt (1.5 wt%) in the base material SnO2 sintered at 800°C showed high sensitivity towards LPG at an operating temperature of 350°C suggestingthe possibility to utilize the sensor for the detection of LPG.

Effect of Gallium and Indium Co-Substituting on Upconversion Properties of Er/Yb:Yttrium Aluminum Garnet Powders Prepared by the Co-Precipitation Method

2016 ◽  
Vol 16 (4) ◽  
pp. 3517-3521 ◽  
Author(s):  
Wei Zhang ◽  
Yun-Ling Liang ◽  
Zheng-Fa Hu ◽  
Zu-Yong Feng ◽  
Ma Lun ◽  
...  
Keyword(s):  
Emission Spectrum ◽  
Infrared Spectra ◽  
Formation Process ◽  
Photoelectron Spectroscopy ◽  
Blue Shift ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermo Gravimetry ◽  
Co Precipitation

Gallium and Indium co-substituted Yb, Er:YAG was fabricated through the chemical co-precipitation method. The formation process and structure of the Ga3+ and In3+ substituted phosphor powders were characterized by the X-ray diffraction, thermo-gravimetry analyzer, infrared spectra, and X-ray photoelectron spectroscopy, and the effects of Ga3+ and In3+ concentration on the luminescence properties were investigated by spectrum. The results showed that the blue shift occurred after the substitution of Ga3+ and In3+ for Al3+ in matrix, and the intensity of emission spectrum was affected by the concentration of Ga3+ and In3+.

scholarly journals Assessing magnetic and inductive thermal properties of various surfactants functionalised Fe3O4 nanoparticles for hyperthermia

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Arunima Rajan ◽  
Madhulika Sharma ◽  
Niroj Kumar Sahu
Keyword(s):  
Magnetic Susceptibility ◽  
Relaxation Time ◽  
Photoelectron Spectroscopy ◽  
Precipitation Method ◽  
Ammonium Bromide ◽  
Inductive Heating ◽  
Magnetic Studies ◽  
X Ray ◽  
Heating Efficiency ◽  
Co Precipitation

Abstract This work reports the fabrication of magnetite (Fe3O4) nanoparticles (NPs) coated with various biocompatible surfactants such as glutamic acid (GA), citric acid (CA), polyethylene glycol (PEG), polyvinylpyrrolidine (PVP), ethylene diamine (EDA) and cetyl-trimethyl ammonium bromide (CTAB) via co-precipitation method and their comparative inductive heating ability for hyperthermia (HT) applications. X-ray and electron diffraction analyses validated the formation of well crystallined inverse spinel structured Fe3O4 NPs (crystallite size of ~ 8–10 nm). Magnetic studies confirmed the superparamagnetic (SPM) behaviour for all the NPs with substantial magnetisation (63–68 emu/g) and enhanced magnetic susceptibility is attributed to the greater number of occupations of Fe2+ ions in the lattice as revealed by X-ray photoelectron spectroscopy (XPS). Moreover, distinctive heating response (specific absorption rate, SAR from 130 to 44 W/g) of NPs with similar size and magnetisation is observed. The present study was successful in establishing a direct correlation between relaxation time (~ 9.42–15.92 ns) and heating efficiency of each surface functionalised NPs. Moreover, heat dissipated in different surface grafted NPs is found to be dependent on magnetic susceptibility, magnetic anisotropy and magnetic relaxation time. These results open very promising avenues to design surface functionalised magnetite NPs for effective HT applications.

Effect of Zn2+ and F− Co-Modification on the Structure and Electrochemical Performance of Li4Ti5O12 Anode Material

NANO ◽  
2017 ◽  
Vol 12 (05) ◽  
pp. 1750054 ◽  
Author(s):  
Aijia Wei ◽  
Wen Li ◽  
Lihui Zhang ◽  
Xiaohui Li ◽  
Xue Bai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Coating Layer ◽  
Rate Capability ◽  
Precipitation Method ◽  
Charge Capacity ◽  
X Ray ◽  
Modification Process ◽  
Co Precipitation ◽  
A Charge

Zn[Formula: see text] and F[Formula: see text] ions are successfully used to modify pure Li4Ti5O[Formula: see text] via a co-precipitation method followed by calcination at 400[Formula: see text]C for 5[Formula: see text]h in an Ar atmosphere in order to further investigate the reaction mechanism of the fluoride modification process. Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. After the modification process, no ZnF2 coating layer is formed on the surface of Li4Ti5O[Formula: see text], instead, F[Formula: see text] ions react with Li4Ti5O[Formula: see text] to generate a new phase, composed of a small amount of anatase TiO2, rutile TiO2, LiF, and Zn[Formula: see text] ions are suspected to form a ZnO coating layer on Li4Ti5O[Formula: see text] particles. The electrolyte reduction decomposition is suppressed in Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] due to the ZnO coating layer. 1[Formula: see text]wt.% Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] exhibits the best rate capability, which leads to a charge capacity of 236.7, 227.8, 222.1, 202.7, 188.9 and 150.7[Formula: see text]mAh g[Formula: see text] at 0.2C, 0.5C, 1C, 3C, 5C and 10C, respectively, between 0[Formula: see text]V and 3[Formula: see text]V. Furthermore, 1[Formula: see text]wt.% Zn[Formula: see text] and F[Formula: see text] co-modified Li4Ti5O[Formula: see text] exhibits 96.0% charge capacity retention at 3C rate after 200 cycles, which is significantly higher than that of pure Li4Ti5O[Formula: see text] (78.4%).

scholarly journals Differentiating Nanomaghemite and Nanomagnetite and Discussing Their Importance in Arsenic and Lead Removal from Contaminated Effluents: A Critical Review

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2310
Author(s):  
Juan A. Ramos-Guivar ◽  
Diego A. Flores-Cano ◽  
Edson Caetano Passamani
Keyword(s):  
Heavy Metal ◽  
Iron Oxides ◽  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Magnetic Circular Dichroism ◽  
Cost Evaluation ◽  
Precipitation Method ◽  
Lead Removal ◽  
X Ray ◽  
Co Precipitation

Arsenic and lead heavy metals are polluting agents still present in water bodies, including surface (lake, river) and underground waters; consequently, the development of new adsorbents is necessary to uptake these metals with high efficiency, quick and clean removal procedures. Magnetic nanoparticles, prepared with iron-oxides, are excellent candidates to achieve this goal due to their ecofriendly features, high catalytic response, specific surface area, and pulling magnetic response that favors an easy removal. In particular, nanomagnetite and maghemite are often found as the core and primary materials regarding magnetic nanoadsorbents. However, these phases show interesting distinct physical properties (especially in their surface magnetic properties) but are not often studied regarding correlations between the surface properties and adsorption applications, for instance. Thus, in this review, we summarize the main characteristics of the co-precipitation and thermal decomposition methods used to prepare the nano-iron-oxides, being the co-precipitation method most promising for scaling up processes. We specifically highlight the main differences between both nano-oxide species based on conventional techniques, such as X-ray diffraction, zero and in-field Mössbauer spectroscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism, the latter two techniques performed with synchrotron light. Therefore, we classify the most recent magnetic nanoadsorbents found in the literature for arsenic and lead removal, discussing in detail their advantages and limitations based on various physicochemical parameters, such as temperature, competitive and coexisting ion effects, i.e., considering the simultaneous adsorption removal (heavy metal–heavy metal competition and heavy metal–organic removal), initial concentration, magnetic adsorbent dose, adsorption mechanism based on pH and zeta potential, and real water adsorption experiments. We also discuss the regeneration/recycling properties, after-adsorption physicochemical properties, and the cost evaluation of these magnetic nanoadsorbents, which are important issues, but less discussed in the literature.

Phosphate removal from aqueous solution by Fe-La binary (hydr)oxides: A study of batch experiments and mechanisms

2021 ◽  
Author(s):  
Haijing Duan ◽  
Lin Zhang ◽  
Yu-long Wang ◽  
Yanhong Liu ◽  
Yangyang Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Efficiency ◽  
Ph Value ◽  
Phosphate Removal ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Batch Experiments ◽  
Exchange Reactions ◽  
X Ray ◽  
Co Precipitation

Abstract In this study, Fe-La binary (hydr)oxides were prepared by a co-precipitation method for phosphate removal. Various techniques, including secondary electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), powder X-ray diffraction (p-XRD) and Brunauer-Emmett-Teller (BET) surface area analysis, were employed to characterize the synthesized Fe-La binary (hydr)oxides. Batch experiments indicated that the performance of phosphate removal by Fe-La binary (hydr)oxides was excellent and increased with increasing La contents. The kinetics study showed that the adsorption was rapid and described better by the pseudo-second-order equation. The maximum adsorption capacities of Fe/La 3:1, Fe/La 1:1 and Fe/La 1:3 binary (hydr)oxides at pH 4.0 calculated by Langmuir model were 49.02, 69.44 and 136.99 mg/g, respectively. The uptake of phosphate was highly affected by solution pH and significantly reduced with the increase of pH value. The analyses of p-XRD, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) suggested that the predominant mechanisms of phosphate removal involved surface hydroxyl exchange reactions and co-precipitation of released La3+ and phosphate ions, which resulted into the formation of amorphous phase of rhabdophane (LaPO4∙0.5H2O). The results show great potential for the application on the treatment of phosphate decontamination for their high efficiency of phosphate removal.

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