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Photocatalytic degradation of phenol by LaFeO3 nanocrystalline synthesized by gel combustion method via citric acid route
摘要： Focusing on the photocatalytic degradation of phenol under visible light, the synthesized lanthanum orthoferrites (LaFeO3) by gel combustion method using citric acid as sacrificial agent were investigated. With the highest reaction temperature of 200 °C, the physicochemical properties of synthesized samples were characterized by X-Ray diffraction (XRD) analysis, Brunauer–Emmet–Teller (BET), and Energy Dispersive X-Ray spectroscopy (EDS). On the other hand, UV–Vis spectroscopy analysis was carried out to determine the phenol photodegradation activities and mechanism. The results suggested the well-defined LaFeO3 nanocrystals with specific area of 28 m2 g?1 were successfully synthesized. Besides that, variations in operating parameters such as pH, catalyst dosage and initial concentration of phenol in synthetic wastewater were also examined. In conclusion, LaFeO3 nanocrystalline exhibited an exceptional photocatalytic activity for phenol degradation, thus providing a perfect alternative for pharmaceutical wastewater treatment.
关键词： Citric acid,Photocatalytic activity,Lanthanum orthoferrite,Phenol,Gel combustion
更新于2025-09-23 15:23:52
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Synthesis and photocatalytic activity of BiOBr hierarchical structures constructed by porous nanosheets with exposed (110) facets
摘要： BiOBr hierarchical structures were successfully synthesized through a solvothermal process assisted with citric acid using methanol as a solvent. The as-synthesized BiOBr hierarchical structures have diameters of ca. 1 μm, and assembled by numerous porous nanosheets with exposed (110) facets. Results indicated that the crystal growth and morphology structures of BiOBr were significantly influenced by the amount of citric acid, the solvothermal time and the solvent used in reaction. In addition, the as-synthesized BiOBr hierarchical structures exhibited high photocatalytic activity on the degradation of methyl orange under either UV light or simulated sunlight illumination, due to the larger specific surface area and unique hierarchical structures assembled by numerous BiOBr porous nanosheets.
关键词： photocatalytic,citric acid,hierarchical structures,solvothermal,BiOBr
更新于2025-09-23 15:22:29
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Copper doped nickel aluminate: Synthesis, characterisation, optical and colour properties
摘要： Novel environment friendly inorganic nano green pigments, Ni1-xCuxAl2O4 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) were successfully synthesized by simple, cost effective sol-gel method using citric acid as a gelling agent. Synthesized nano pigments were characterised by powder XRD, FT-IR, UV-DRS, SEM-EDX and TEM. Distribution of elements such as Ni, Cu, Al and O for the pigment Ni0.98Cu0.02Al2O4 was authenticated by elemental mapping analysis. The color parameters were studied using CIE-LAB parameters. It is evident from the DRS measurement that the band gap energy of NiAl2O4 (3.11eV) has been massively diminished to 2.63 eV when x = 0.02, unexpectedly changed the color of the pigment from cyan to green. While x = 0.1 the pigment color has turned into grey and the corresponding band gap condensed into 2.17 eV. Effect of mineralisers like NaF, CaF2, NH4H2PO4 and Li2CO3 on the color of Ni0.98Cu0.02Al2O4 was investigated.
关键词： chemical resistance,sol-gel,citric acid,Nickel aluminate,green pigment
更新于2025-09-23 15:22:29
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Peripherally functionalized based dendrimers as the template for synthesis of silver nanoparticles and investigation the affecting factors on their properties
摘要： Today, dendrimers (D) were introduced as a versatile template for the synthesis of nanoparticles (NPs). In this work, the stable silver nanoparticles (AgNPs) is successfully synthesized through the chemical reduction of AgNO3 using NaBH4 as a reducing agent. Synthesis of AgNPs was performed in the presence of different generations of citric acid-based dendrimers (G1, G2 and G3) and hydroxyl-terminated citric acid-based dendrimers (G1-OH, G2-OH and G3-OH). High-resolution transmission electron microscopy, electron diffraction and energy-dispersive X-ray analysis were used to characterize the synthesized AgNPs. UV–Vis results were used for the qualitative study of the synthesized AgNPs properties. With varying the molar ratio of dendrimer/Ag+, generations of dendrimers and the pH of the solution, the size and size distribution of AgNPs could be easily controlled at room temperature. The average diameter of the synthesized AgNPs in the presence of Gn-OH was in the range of 8–20 nm. Results show that G1-OH alkaline medium with 1:1 molar ratio of D/Ag is the optimum condition for the synthesis of AgNPs. All the obtained results from this study showed that controlling the medium conditions allows AgNPs with the desired size to be obtained.
关键词： Chemical reduction,Silver nanoparticles,Citric acid,Hydroxyl-terminated dendrimer,Dendrimer
更新于2025-09-23 15:21:01
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Co2+a??coordinated NH2a??carbon quantum dots hybrid precursor for the rational synthesis of Coa??CoOX/Coa??Na??C ORR catalyst
摘要： For the goal of practical industrial development of fuel cells, design and synthesis of electrocatalysts for oxygen reduction reactions (ORR) with sustainable and high performance are of great significance. In this work, the coordination of NH2-carbon quantum dots (NCQDs) with Co2+ on carbon black was reasonably achieved via one-pot and low-cost hydrothermal treatment for the first time. Citric acid (CA) and urea (UA) were taken as carbon and nitrogen sources for NCQDs, respectively. The coordination of Co2+ and NCQDs were well-characterized using spectroscopic techniques such as FTIR, UV-visible absorption and fluorescence. Carbonization of carbon black-supported Co/NCQDs at 800 oC under N2 atmosphere endows the pyrolysis products with high catalytic activity. The Co-CoOX/Co-N-C possesses enhanced ORR performance in terms of positive onset-potential (～-0.079 V vs. SCE) and half wave potential (E1/2) (～-0.201 V vs. SCE), high stability, as well as the accelerated reaction kinetics.
关键词： urea (UA),Citric acid (CA),oxygen reduction reactions (ORR),NH2-carbon quantum dots (NCQDs)
更新于2025-09-23 15:19:57
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Bright Cool White Emission from Ultrasmall CdSe Quantum Dots
摘要： In this work we employ a post-synthesis ligand treatment of ultrasmall CdSe quantum dots (QDs) with citric acid to increase the quantum yield (QY) of the of the as-synthesized CdSe from an average of 5.7% to a maximum of 61.3%. This is the highest reported value for a single component white-light emitting QD. The white-light emission of the ultrasmall CdSe quantum dots is derived from three surface states: pinned emission at a trap state associated with the phosphonic acid surface ligand, a surface Se state, and conventional deep trap states. The citric acid treated CdSe QDs were found to recover band gap emission from the phosphonic acid ligand trap state emission, exhibiting behavior . This band gap emission peak also becomes more prominent, resulting in a cooler white, as indicated by the shift in the CIE coordinates from an average of (0.30, 0.36) to (0.26, 0.32). Comparing to a previous method of increasing the QY by a post-synthesis treatment of formic acid, the citric acid treated CdSe QDs are brighter as well as more stable in solution over time, which opens the possibility for use in multiple applications.
关键词： white-light emission,quantum yield,quantum dots,citric acid,CdSe
更新于2025-09-12 10:27:22
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Synthesis of magnetically reusable Fe3O4/TiO2-N, P co-doped graphene quantum dot nancomposites using hexachlorocyclophosphazene; high photoluminance property and photocatalytic promoter
摘要： Hexachlorocyclophosphazene (PNT) was used as new P and N doping source for synthesizing of graphene quantum dots (N,P-GQDs). Hydrothermal process was applied for importing P and N atoms into the GQDs texture. Three different amounts of hexachlorocyclophosphazene were used to obtain optimum sample. All products were characterized using XRD, SEM, PL, FT-IR, EDS, AFM, TEM and Raman spectroscopy. XRD result indicated that the sample with 0.1 g of PNT (sample 2) has sharp peaks with medium wide and intensity and has a more principle in structure in comparison with other samples. So sample 2 was chosen as optimum sample. Also sample 2 showed strongest PL emission under excitation at 396 nm which was an evidence of successful doping of P and N atoms in the GQDs structure during hydrothermal process. The Fe3O4/TiO2/N,P-GQDs nanocomposite which was obtained using S2 as N,P-GQDs source showed a high activity in organic dye degradation. The higher catalytic activity of Fe3O4/TiO2/N,P-GQDs versus TiO2 can be attributed to the synergistic effect between TiO2 and N,P-GQDs. The magnetic properties of the catalysts allow fast separation of the catalysts from the reaction media.
关键词： Hexachlorocyclophosphazene,Fe3O4/TiO2/N,GQDs,Citric acid,P-GQDs nanocomposite,Photoluminescence
更新于2025-09-11 14:15:04
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Criticial Assessment of the Photocatalytic Reduction of Cr(VI) over Au/TiO2
摘要： The puri?cation of drinking water is one of the most urgent challenges in developing countries, for which the ef?cient removal of traces of heavy metals, e.g., Cr(IV), represents a key technology. This can be achieved via photocatalysis. In this study, we compare the performance of Au/TiO2 to bare TiO2 P25 catalysts. Furthermore, the in?uence of the sacri?cial reagent citric acid under UV-Vis and Vis excitation was investigated and a detailed investigation of the catalysts before and after reaction was performed. During the photocatalytic reduction of Cr(IV) under acidic conditions, both leaching of Au, as well as absorption of Cr, occur, resulting in new catalyst systems obtained in situ.
关键词： Au/TiO2,adsorption,photocatalysis,Cr(VI) reduction,citric acid
更新于2025-09-09 09:28:46
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Citric acid-modulated in situ synthesis of 3D hierarchical Bi@BiOCl microsphere photocatalysts with enhanced photocatalytic performance
摘要： 3D hierarchical Bi@BiOCl microspheres were successfully synthesized by a facile solvothermal method using citric acid as a modulating agent and the growth process was revealed. The modulation of citric acid not only reduced the size of BiOCl nanosheets, finally transforming BiOCl microflowers into microspheres, but also induced the in situ reductive deposition of metallic Bi on the surface of the microspheres. Consequently, Bi@BiOCl microspheres showed larger specific surface areas and total pore volumes, higher absorptivity to the visible light and better charge transfer ability than BiOCl microflowers. As a result, Bi@BiOCl microspheres exhibited much better photocatalytic performance than BiOCl microflowers. Bi@BiOCl microspheres modulated by 2.8 g citric acid showed the highest photocatalytic activity, which was 4.4 and 2.5 times higher than BiOCl microflowers in degrading RhB under visible light and salicylic acid under UV light, respectively. This work may provide a new insight into simultaneous size control and in situ metal deposition for Bi-containing photocatalysts and other materials.
关键词： solvothermal method,Bi@BiOCl microspheres,photocatalytic performance,citric acid modulation,in situ reductive deposition
更新于2025-09-04 15:30:14