scholarly journals Complete Benzene Oxidation over Mono and Bimetallic Pd—Au Catalysts on Alumina-Supported Y-Doped Ceria

2020 ◽  
Vol 10 (3) ◽  
pp. 1088
Author(s):  
Tabakova ◽  
Ilieva ◽  
Petrova ◽  
Venezia ◽  
Karakirova ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Cost Effective ◽  
Catalytic Performance ◽  
Benzene Oxidation ◽  
Doped Ceria ◽  
Mechanical Mixing ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
High Performing ◽  
Catalyst Composition

The protection of environment and human health stimulates intensive research for abatement of volatile organic compounds (VOCs) in the atmosphere. Complete catalytic oxidation is an efficient, environmentally friendly and economically feasible method for elimination of VOCs. This study aims to design high performing and cost-effective catalytic formulations by exploration of appropriate and economically viable supports. Alumina-supported ceria (30 wt.%) and Y2O3 (1 wt.%)-doped ceria were prepared by mechanical mixing and were used as support of mono Au (2 wt.%) and Pd (1 wt.%) and bimetallic Pd-Au catalysts. The characterization by textural measurements, X-ray powder diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), EPR (electron paramagnetic resonance) and temperature-programmed reduction (TPR) was carried out in order to clarify the relationship between catalyst composition, textural, structural and surface properties, reducibility and catalytic performance for complete benzene oxidation. Among all studied catalysts, Pd-based catalysts exhibited the best combustion activity. In particular, monometallic Pd on alumina supported Y-doped ceria attained 100% of complete benzene conversion at 180 °C. These catalytic materials have potential to meet stringent emission regulations in an economical and effective way.

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 NiO-NiFe2O4-rGO Magnetic Nanomaterials for Activated Peroxymonosulfate Degradation of Rhodamine B

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 384 ◽  
Author(s):  
Xiaochen Xu ◽  
Yanfang Li ◽  
Guoquan Zhang ◽  
Fenglin Yang ◽  
Ping He
Keyword(s):  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Heterogeneous Catalysts ◽  
Degradation Process ◽  
Catalytic Performance ◽  
Active Species ◽  
Environmental Benefits ◽  
Magnetic Nanomaterials ◽  
Paramagnetic Resonance ◽  
X Ray

Magnetic spinel ferrites that act as heterogeneous catalysts and generate powerful radicals from peroxymono-sulfate (PMS) for the degradation of organic pollutants have received much attention in recent years due to the characteristic of environmental benefits. In this study, NiO-NiFe2O4-rGO magnetic nanomaterials were synthesized using a calcinated Ni-Fe-LDH-rGO precursor. The morphology, structure, and chemical constitution were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM). The catalytic performance of NiO-NiFe2O4-rGO nanoparticles was thoroughly evaluated for peroxymonosulfate (PMS) activation and its removal of rhodamine B (RhB) from water. The influence of different process parameters on the RhB degradation efficiency was examined. Further, the catalytic stability was evaluated. Under optimized conditions, the NiO-NiFe2O4-rGO/PMS system was very efficient; RhB fully degraded after 40 min at room temperature. Quenching experiments and electronic paramagnetic resonance (EPR) results suggested that SO4−· and OH· were the main active species in the degradation process. Moreover, NiO-NiFe2O4-rGO catalyst was stable without any apparent activity loss after three cycling runs.

Jellyfish-like few-layer graphene nanoflakes: high paramagnetic response alongside increased interlayer interaction

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander Ulyanov ◽  
Dmitrii Stolbov ◽  
Serguei Savilov
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Sensitivity ◽  
Paramagnetic Centers ◽  
Interlayer Interaction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Graphene Nanoflakes ◽  
Few Layer Graphene ◽  
Electron Paramagnetic ◽  
Hydrocarbon Pyrolysis

Abstract Jellyfish-like graphene nanoflakes (GNF), prepared by hydrocarbon pyrolysis, are studied with electron paramagnetic resonance (EPR) method. The results are supported by X-ray photoelectron spectroscopy (XPS) data. Oxidized (GNFox) and N-doped oxidized (N-GNFox) flakes exhibit an extremely high EPR response associated with a large interlayer interaction which is caused by the structure of nanoflakes and layer edges reached by oxygen. The GNFox and N-GNFox provide the localized and mobile paramagnetic centers which are silent in the pristine (GNF p ) and N-doped (N-GNF) samples. The change in the relative intensity of the line corresponding to delocalized electrons is parallel with the number of radicals in the quaternary N-group. The environment of localized and mobile electrons is different. The results can be important in GNF synthesis and for explanation of their features in applications, especially, in devices with high sensitivity to weak electromagnetic field.

Mixed Metal Oxide Interfaces: An Experimental and Theoretical Assessment of Secondary Metal Influences in Metal Impregnated Aluminas

1994 ◽  
Vol 368 ◽  
Author(s):  
M. Malaty ◽  
D. Singh ◽  
R. Schaeffer ◽  
S. Jansen ◽  
S. Lawrence
Keyword(s):  
Photoelectron Spectroscopy ◽  
Theoretical Calculations ◽  
Mixed Metal Oxide ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Mixed Metal ◽  
Metal Interactions ◽  
Metal Metal ◽  
Bimetallic System

ABSTRACTStudies of the mixed-metal interface in metal impregnated alumina have indicated the possibility of much metal-metal and metal-substrate interaction. Studies were carried out on NiCu/Al2O3 system which was evaluated to develop a better understanding of the forces that drive modification of the catalytic selectivity of Ni in the presence of Cu. Electron Paramagnetic Resonance (EPR), Powder X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD) and theoretical calculations were carried out on this bimetallic system, using Ni,Ag/Al2O3 as a reference as Ni shows negligible electron perturbation on co-adsorbance with Ag onto alumina. XRD results indicate that gross modification of the electronic fields of Ni and Cu are due to direct coupling and intercalation into the alumina matrix. As a result of this phenomena, these materials may form a good base for the development of novel ceramics based on mixed-metal interactions where the intermetallic perturbations are driven by the substrate effects.

Silver mirror reaction metallized chromatography paper for supercapacitor application

2021 ◽  
Author(s):  
I-Hsuan Chen ◽  
Jung-Hsien Chang ◽  
Ren-Jie Xie ◽  
Chia-Hui Tseng ◽  
Sheng-Rong Hsieh ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Photoelectron Spectroscopy ◽  
Cost Effective ◽  
Water Contact ◽  
X Ray ◽  
Supercapacitor Application ◽  
Resource Limited ◽  
Vis Spectroscopy ◽  
Silver Mirror ◽  
Silver Mirror Reaction

Abstract In this study, the easy-to-operate silver mirror reaction (SMR) was used for metallizing chromatography paper. The SMR-metallized paper was characterized by water contact angle measurements, a surface profiler, X-ray photoelectron spectroscopy, UV-vis spectroscopy, X-ray diffraction, and electrical resistance measurement. The characterization results show that Ag was successfully synthesized on cellulose fibers and was electrically conductive after cyclic bending. Moreover, this SMR-metallized paper was used as electrodes for fabricating a supercapacitor. This SMR-metallized paper could be used for realizing cost-effective flexible electronics applied in on-site biochemical sensing in resource-limited settings.

Use of anti-solvent to enhance thermoelectric response of hybrid-halide perovskite thin films

2022 ◽  
Author(s):  
Shrikant SAINI ◽  
Izuki Matsumoto ◽  
Sakura Kishishita ◽  
Ajay Kumar Baranwal ◽  
Tomohide Yabuki ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Cost Effective ◽  
Performance Tuning ◽  
Charge Carrier Density ◽  
X Ray ◽  
Thermoelectric Energy Harvesting ◽  
Halide Perovskite

Abstract Hybrid halide perovskite has been recently focused on thermoelectric energy harvesting due to the cost-effective fabrication approach and ultra-low thermal conductivity. To achieve high performance, tuning of electrical conductivity is a key parameter that is influenced by grain boundary scattering and charge carrier density. The fabrication process allows tuning these parameters. We report the use of anti-solvent to enhance the thermoelectric performance of lead-free hybrid halide perovskite, CH3NH3SnI3, thin films. Thin films with anti-solvent show higher connectivity in grains and higher Sn+4 oxidation states which results in enhancing the value of electrical conductivity. Thin films were prepared by a cost-effective wet process. Structural and chemical characterizations were performed using x-ray diffraction, scanning electron microscope, and x-ray photoelectron spectroscopy. The value of electrical conductivity and the Seebeck coefficient were measured near room temperature. The high value of power factor (1.55 µW/m.K2 at 320 K) was achieved for thin films treated with anti-solvent.

Preparation of Novel Ag–Si–TiO2 Composite and Research on Its Photocatalytic Degradation of Formaldehyde

2021 ◽  
Vol 13 (3) ◽  
pp. 371-380
Author(s):  
Yongjun Wu ◽  
Nina Xie ◽  
Lu Yu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Removal Rate ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Formaldehyde Concentration ◽  
Order Kinetic ◽  
Solution Ph ◽  
Visible Absorption ◽  
X Ray ◽  
Co Doped

A novel Ag–Si–TiO2 composite was prepared via sol–gel method for removing residual formaldehyde in shiitake mushroom. The structure of Ag–Si–TiO2 composite was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Ultraviolet-visible absorption spectroscopy (UV-Vis) and N2 adsorption-desorption tests showed that Ag and Si co-doped decreased the band gap, the Brunauer-Emmett-Teller (BET) specific surface area of the samples increased and the recombination probability of electron-hole pairs (e--h+) reduced. Effect on removal rate of formaldehyde with different Ag-Si co-doped content, formaldehyde concentration and solution pH were investigated, and the results showed that 6.0 wt%Ag-3.0 wt%Si-TiO2 samples had an optimum catalytic performance, and the degradation efficiency reached 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation by Ag–Si–TiO2 composite photocatalyst could be described by Langmuir-Hinshelwood first-order kinetic model.

scholarly journals Influence of Sulfur-Containing Sodium Salt Poisoned V2O5–WO3/TiO2 Catalysts on SO2–SO3 Conversion and NO Removal

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 541 ◽  
Author(s):  
Haiping Xiao ◽  
Chaozong Dou ◽  
Hao Shi ◽  
Jinlin Ge ◽  
Li Cai
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Reduction ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Impregnation Method ◽  
So2 Oxidation ◽  
Sodium Salts ◽  
X Ray ◽  
Temperature Programmed ◽  
Physical Features

A series of poisoned catalysts with various forms and contents of sodium salts (Na2SO4 and Na2S2O7) were prepared using the wet impregnation method. The influence of sodium salts poisoned catalysts on SO2 oxidation and NO reduction was investigated. The chemical and physical features of the catalysts were characterized via NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed that sodium salts poisoned catalysts led to a decrease in the denitration efficiency. The 3.6% Na2SO4 poisoned catalyst was the most severely deactivated with denitration efficiency of only 50.97% at 350 °C. The introduction of SO42− and S2O72− created new Brønsted acid sites, which facilitated the adsorption of NH3 and NO reduction. The sodium salts poisoned catalysts significantly increased the conversion of SO2–SO3. 3.6%Na2S2O7 poisoned catalyst had the strongest effect on SO2 oxidation and the catalyst achieved a maximum SO2–SO3-conversion of 1.44% at 410 °C. Characterization results showed sodium salts poisoned catalysts consumed the active ingredient and lowered the V4+/V5+ ratio, which suppressed catalytic performance. However, they increased the content of chemically adsorbed oxygen and the strength of V5+=O bonds, which promoted SO2 oxidation.

Synthesis of Novel g-C3N4/NH2-MIL-88B(Fe) Composite Photocatalysis for Efficient Ciprofloxacin Degradation Under Simulated Sunlight Irradiation

NANO ◽  
2021 ◽  
pp. 2150063
Author(s):  
Jungang Yi ◽  
Kun Wu ◽  
Huadong Wu ◽  
Jia Guo ◽  
Linfeng Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Adsorption Property ◽  
Catalytic Performance ◽  
Step Method ◽  
Area Formula ◽  
Aquatic Life ◽  
X Ray ◽  
Transmission Electron ◽  
Uniform Dispersion ◽  
Composite Photocatalysts

The presence of the antibiotics in the wastewater has posed a huge risk to aquatic life and human health. It is a great significance to develop an effective technology to treat the antibiotics-containing wastewater. In this study, a series of g-C3N4/NH2-MIL-88B(Fe) composite photocatalysts are synthesized through a simple one-step method. The structure and optical properties of prepared photocatalysts are detected by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–Vis absorption spectra (UV–Vis DRS), photoluminescence (PL) spectroscopy and transient photocurrent techniques, respectively. FESEM and TEM show that MOF is uniformly dispersed in petaloid g-C3N4. The uniform dispersion of Fe-MOFs in the heterojunction composites increases the specific surface area ([Formula: see text] of g-C3N4, which results in a great adsorption property for the nanocomposite. The capture experiment shows that [Formula: see text]O[Formula: see text] and h[Formula: see text] are the main active substances in ciprofloxacin (CIP) degradation. These prepared composite photocatalysts exhibit excellent CIP photodegradation activity under visibly light irradiation with an apparent rate constant of 0.0127[Formula: see text]min[Formula: see text] (3.74 times as the rate of single component). The remarkable catalytic performance can be ascribed to the fact that the g-C3N4/NH2-MIL-88B(Fe) heterojunction inhibits the recombination of photoinduced electron–hole pairs and improved the visible light absorption.

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