Sunlight-Driven AO7 Degradation with Perovskites (La,Ba)(Fe,Ti)O3 as Heterogeneous Photocatalysts

Perovskites of the (La,Ba)(Fe,Ti)O3 family were prepared, characterized, and utilized as heterogeneous photocatalysts, activated by natural sunlight, for environmental remediation of Acid Orange 7 (AO7) aqueous solutions. Catalysts were prepared by the ceramic (CM) and the complex polymerization (CP) methods and characterized by XRD, SEM, EDS, and band gap energy. It was found that catalytic properties depend on the synthesis method and annealing conditions. In the photocatalytic assays with sunlight, different AO7 initial concentrations and perovskite amounts were tested. During photocatalytic assays, AO7 and degradation products concentrations were followed by HPLC. Only photocatalysis with BaFeO3-CM and BaTiO3-CP presented AO7 removals higher than that observed for photolysis. However, photolysis leads to the formation of almost exclusively amino-naphthol and sulfanilic acid, whereas some of the perovskites utilized form less-toxic compounds as degradation products, such as carboxylic acids (CA). Partial substitution of Ba by La in BaTiO3-CM does not produce any change in the photocatalytic properties, but the replacement of Ti by Fe in the La0.1Ba0.9TiO3 leads to reduced AO7 removal rate, but with the formation of CAs. The best AO7 removal (92%) was obtained with BaFeO3-CM (750 mg L−1), after 4 h of photocatalytic degradation with solar radiation.

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Novel Route to Obtain Carbon Self-Doped TiO2 Mesoporous Nanoparticles as Efficient Photocatalysts for Environmental Remediation Processes under Visible Light

Materials ◽

10.3390/ma12203349 ◽

2019 ◽

Vol 12 (20) ◽

pp. 3349 ◽

Cited By ~ 1

Author(s):

Pablo A. Ochoa Rodríguez ◽

Tamara B. Benzaquén ◽

Gina A. Pecchi ◽

Sandra G. Casuscelli ◽

Verónica R. Elías ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Environmental Remediation ◽

Synthesis Method ◽

Mesoporous Structure ◽

Acid Orange 7 ◽

X Ray Diffraction ◽

Visible Radiation ◽

X Ray ◽

Transmission Electron ◽

Adsorption Desorption

Titanium dioxide materials were synthesized using two different methods. The samples were characterized by X-ray diffraction (XRD), UV–Visible diffusion reflectance spectroscopy (UV-Vis DR), Raman spectroscopy, N2 adsorption/desorption, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron spectroscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Although both kind of materials were found to have mesoporous structure and anatase crystalline phase, one of them was obtained from a synthesis method that does not involve the use of surfactants, and therefore, does not require calcination at high temperatures. This implies that the synthesized solid was self-doped with carbon species, coming only from the same source used for titanium. Then, the relationship between the presence of these species, the final calcination temperature, and the photocatalytic activity of the solids was studied in terms of the degradation and mineralization of an Acid Orange 7 aqueous solution, under visible radiation. A photosensitizing effect caused by the non-metal presence, that allows the solid to extend its absorption range, was found. Hence, a novel route to prepare C-modified photoactive mesoporous TiO2, simpler and cheaper, where neither a template nor an external carbon source is used, could be performed.

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Effects on the physicochemical properties of partial substitution of Ni for Co in NixCo3-xO4 (x= 0, 0.4, 0.8) nickel-cobalt spinels using a new synthesis method (Pechini technique)

European Journal of Control ◽

10.3166/acsm.31.49-59 ◽

2006 ◽

Vol 31 (1) ◽

pp. 49-59

Author(s):

Makhtar Guene ◽

Abdou Aziz Diagne ◽

Modou Fall ◽

Mor Marème Dieng ◽

Gérard Poillerat

Keyword(s):

Physicochemical Properties ◽

Synthesis Method ◽

Partial Substitution ◽

Nickel Cobalt ◽

New Synthesis

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Effect of Fe3+ Partial Substitution at Mn-Site on Electroresistance Behaviour in La0.7Ba0.3Mn1-xFexO3 (x = 0 and 0.02) Manganites

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.317.3 ◽

2021 ◽

Vol 317 ◽

pp. 3-9

Author(s):

Muhammad Suffian Sazali ◽

Norazila Ibrahim ◽

Zakiah Mohamed ◽

Rozilah Rajmi ◽

Ahmad Kamal Yahya

Keyword(s):

Synthesis Method ◽

Partial Substitution ◽

X Ray Diffraction ◽

Applied Current ◽

Conduction Path ◽

Magnetic Inhomogeneity ◽

Temperature Range ◽

Refinement Method ◽

Non Volatile Memory ◽

Fe Substitution

La0.7Ba0.3Mn1-xFexO3 (x = 0 and 0.02) were prepared by using solid state synthesis method to investigate the effect of Fe3+ substitution at Mn-site on electrical behaviour and structural properties. An analysis of X-ray diffraction, XRD data using refinement method shown both x = 0 and x = 0.02 samples were in single phased and crystallized in rhombohedral structural with Pnma space group. From ρ vs T curves shown resistivity decreased under increased of applied current of 10 mA to 20 mA for both samples in the temperature range of 20 K-300 K. The larger electroresistance, ER effect observed for x = 0.02 in temperature range of 20 K – 180 K compared to x = 0 sample is suggested due to the development of filamentary conduction path under increased of applied current. It is suggested that Fe substitution enhanced magnetic inhomogeneity which contribute to the growth of formation of conductive path under increased of applied current, lead to increase of ER effect. In the temperature range of 180 K – 300 K, the observed decreased in ER for Fe substituted sample (x = 0.02) is suggested due to the increased of scattering effect and reduction of available hopping site in metallic region and insulating region, respectively. Restriction in the movement of charge carrier had weakened the ER effect for Fe substituted sample. The observed ER effect indicates the compound has a potential for application such as for non-volatile memory elements.

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Nb2O5 nanoparticles obtained by microwave assisted combustion synthesis under different conditions

Processing and Application of Ceramics ◽

10.2298/pac2102128l ◽

2021 ◽

Vol 15 (2) ◽

pp. 128-135

Author(s):

Thaís Luiz ◽

Fabio Nakagomi ◽

Reny Renzetti ◽

Guilherme Siqueira

Keyword(s):

Combustion Synthesis ◽

Diffuse Reflectance Spectroscopy ◽

Low Cost ◽

Synthesis Method ◽

Particle Growth ◽

Synthesis Temperature ◽

Band Gap Energy ◽

Stoichiometric Ratio ◽

Synthesis Of Nanoparticles ◽

Microwave Assisted

The microwave assisted combustion synthesis (MACS) as a new, quick and low cost synthesis method was used for preparation of niobium pentoxide (Nb2O5) powders. The present paper investigated the effect of reactant concentrations (ammonium niobium oxalate, urea and ammonium nitrate) on the characteristics of Nb2O5 nanoparticles. Three samples were synthesized with stoichiometric ratio between the fuel and oxidant (C1), excess of oxidant (C2) and excess of fuel (C3). In all samples, Nb2O5 crystalline nanoparticles with irregular morphology were detected. The synthesis of nanoparticles with smaller diameter in the C2 and C3 samples was confirmed by greater values of band gap energy measured through UV-Visible diffuse reflectance spectroscopy (indicating quantum confinement) and by the Rietveld refinement of X-ray diffraction patterns. The results showed that the amounts of oxidant and fuel can change synthesis temperature, influencing the final characteristics of the particles, such as size and existent phases. In these cases the excess of oxidant and fuel in the C2 and C3 samples, respectively, decreases the average synthesis temperature and decelerates the particle growth and the formation of the monoclinic phase.

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Advanced Oxidation Process for Degradation of Carbamazepine from Aqueous Solution: Influence of Metal Modified Microporous, Mesoporous Catalysts on the Ozonation Process

Catalysts ◽

10.3390/catal10010090 ◽

2020 ◽

Vol 10 (1) ◽

pp. 90 ◽

Cited By ~ 3

Author(s):

Soudabeh Saeid ◽

Matilda Kråkström ◽

Pasi Tolvanen ◽

Narendra Kumar ◽

Kari Eränen ◽

...

Keyword(s):

Heterogeneous Catalysts ◽

Advanced Oxidation Process ◽

Degradation Products ◽

Degradation Kinetics ◽

Removal Rate ◽

Influence Of Temperature On ◽

Two Temperatures ◽

Kinetics Of ◽

Ozonation Process ◽

Mcm 41

Carbamazepine (CBZ), a widely used pharmaceutical compound, is one of the most detected drugs in surface waters. The purpose of this work was to identify an active and durable catalyst, which, in combination with an ozonation process, could be used to remove CBZ and its degradation products. It was found that the CBZ was completely transformed after ozonation within the first minutes of the treatment. However, the resulting degradation products, 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM) and 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD), were more resistant during the ozonation process. The formation and degradation of these products were studied in more detail and a thorough catalytic screening was conducted to reveal the reaction kinetics of both the CBZ and its degradation products. The work was performed by non-catalytic ozonation and with six different heterogeneous catalysts (Pt-MCM-41-IS, Ru-MCM-41-IS, Pd-H-Y-12-EIM, Pt-H-Y-12-EIM, Pd-H-Beta-300-EIM and Cu-MCM-41-A-EIM) operating at two temperatures 20 °C and 50 °C. The influence of temperature on degradation kinetics of CBZ, BQM and BQD was studied. The results exhibited a notable difference in the catalytic behavior by varying temperature. The higher reactor temperature (50 °C) showed a higher activity of the catalysts but a lower concentration of dissolved ozone. Most of the catalysts exhibited higher removal rate for BQM and BQD compared to non-catalytic experiments in both temperatures. The Pd-H-Y-12-EIM catalyst illustrated a higher degradation rate of by-products at 50 °C compared to other catalysts.

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Perfluorosulfonic acid polymer composites: Effect of the support and synthesis method on the acid and catalytic properties

Molecular Catalysis ◽

10.1016/j.mcat.2020.111006 ◽

2020 ◽

Vol 492 ◽

pp. 111006

Author(s):

Anton P. Koskin ◽

Rodion V. Andreev ◽

Oleg N. Primachenko ◽

Ekaterina I. Shuvarakova ◽

Alexander F. Bedilo

Keyword(s):

Polymer Composites ◽

Catalytic Properties ◽

Synthesis Method ◽

Perfluorosulfonic Acid ◽

Effect Of The Support

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Crystal phase induced band gap energy enhancing the photo-catalytic properties of Zn–Fe2O4/Au NPs: experimental and theoretical studies

Catalysis Science & Technology ◽

10.1039/c9cy00678h ◽

2019 ◽

Vol 9 (12) ◽

pp. 3066-3080 ◽

Cited By ~ 4

Author(s):

Carlos Alberto Huerta-Aguilar ◽

Aida Araceli Ramírez-Alejandre ◽

Pandiyan Thangarasu ◽

Jesus Angel Arenas-Alatorre ◽

Ivan Alejandro Reyes-Dominguez ◽

...

Keyword(s):

Band Gap ◽

Catalytic Properties ◽

Band Gap Energy ◽

Crystal Phase ◽

Theoretical Studies ◽

Visible Absorption ◽

Au Nps ◽

Gap Energy ◽

Experimental And Theoretical Studies

Au NPs on ZnFe2O4 enhances visible absorption, employed for paracetamol oxidation, where peaks were resolved by 2D HPLC.

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Carbon-Based Band Gap Engineering in the h-BN Analytical Modeling

Materials ◽

10.3390/ma13051026 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1026

Author(s):

Mohammad Taghi Ahmadi ◽

Ahmad Razmdideh ◽

Seyed Saeid Rahimian Koloor ◽

Michal Petrů

Keyword(s):

Boron Nitride ◽

Band Gap ◽

Density Functional ◽

Hexagonal Boron Nitride ◽

Tight Binding ◽

Band Gap Energy ◽

Specific Structure ◽

Partial Substitution ◽

Generalized Gradient ◽

Complete Replacement

The absence of a band gap in graphene is a hindrance to its application in electronic devices. Alternately, the complete replacement of carbon atoms with B and N atoms in graphene structures led to the formation of hexagonal boron nitride (h-BN) and caused the opening of its gap. Now, an exciting possibility is a partial substitution of C atoms with B and N atoms in the graphene structure, which caused the formation of a boron nitride composite with specified stoichiometry. BC2N nanotubes are more stable than other triple compounds due to the existence of a maximum number of B–N and C–C bonds. This paper focused on the nearest neighbor’s tight-binding method to explore the dispersion relation of BC2N, which has no chemical bond between its carbon atoms. More specifically, the band dispersion of this specific structure and the effects of energy hopping in boron–carbon and nitrogen–carbon atoms on the band gap are studied. Besides, the band structure is achieved from density functional theory (DFT) using the generalized gradient approximations (GGA) approximation method. This calculation shows that this specific structure is semimetal, and the band gap energy is 0.167 ev.

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The Study on the Treatment of Nitrobenzene Wastewater by Heterogenious Catalysts and Electrode Oxidation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.668.140 ◽

2013 ◽

Vol 668 ◽

pp. 140-144

Author(s):

Su Leng ◽

Rui Yang Chen ◽

Song Yue Chen ◽

Miao Liu

Keyword(s):

Catalytic Oxidation ◽

Catalytic Properties ◽

Ph Value ◽

Removal Rate ◽

The Self ◽

Electrolysis Time ◽

Oxidation Technology ◽

Electro Catalytic Oxidation ◽

La Doped ◽

Reaction Speed

In the paper, the PbO2-Ti electrodes were characterized by SEM, and introduce the self-made catalyst Fe3+/TiO2 into the electrolytic system to treat the nitrobenzene wastewater, in order to improve the reaction speed and the removal rate of COD and NB and form heterogeneous electro-catalytic oxidation technology. In order to confirm the best removal efficiency of COD and NB, the experiment will study the electrolysis time, current intensity, pH value, and the amount of catalyst. The experimental results showed that the surface of La-doped electrode was dense and had good electro-catalytic properties.

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