Бидний тухай
Багш ажилтан
https://main.scientific.net/editing-tool/author/titles/7039/papers/608561/update
In this work, the transition metal copper (Cu) doped Zn1-xCuxO nanoparticles were synthesized by different doping concentration of Cu (x=1, 3, 5 and 7 M%) through surfactant free benzyl alcohol route method in which zinc acetate and copper acetate were selected as precursors. We have carried out the spin polarized density functional calculations based on the plane wave (PW) and projector augmented wave (PAW) methods using the generalized gradient approximation (GGA) by Perdew and Wang (PBE), as implemented in the QUANTUM ESPRESSO package within the framework of density functional theory (DFT). The following electronic states are treated, as valence electrons of Cu(3d104s1), Zn(3d104s2) and O(2s22p4) for atoms. The wave functions and charge densities are expressed as plane waves up to a kinetic energy cutoff of 60 and 300 Ry, respectively. We have done calculations on the hexagonal wurtzite ZnO unit cell and ZnO (3×3×2) supercell including the 36 Zn and 36 O atoms. For the Cu-doped ZnO nanoparticles 2 coppers are placed in the crystal structure at 3 different distances: short, medium, and long. We used the tetrahedral method when we evaluate the electronic total and projected density of state (DOS). For the self-consistent field (SCF) iterations, the total energy convergence is 10- 5 eV. The occupation numbers of electrons are expressed Gaussian distribution function with an electronic temperature of kT = 0.02 Ry. To express the strong correlated effect of electrons in the Cu(3d) and Zn(3d) states, we have chosen to be U = 3.5 and 8.5 eV respectively, using the simplified rotational-invariant formulation based on the linear response method. The numerical error in the magnetic energy gain was 3 meV. The ionic positions are relaxed at the fixed lattice parameters until the residual forces are less than 0.05eV/Å. An experimental result was validated theoretically by performing DFT calculations. Our predicted values of lattice parameters were agreed with our experimental values of crystal structure, in which the errors of the lattice parameter a are 1.14% and 1.01% by the PW and PAW methods, respectively. Our results of magnetism are shown that the hole-mediated ferromagnetism of Cu-doped ZnO is created by the double exchange mechanism, as created localized empty holes on the localized t2g state of Cu ions due to the bound magnetic polarons. These results agree with our experimental results
On place research was conducted cooperating with traditional pasturing and feed supply combined cow farm. It was built a handmade pyrolysis construction direct by the farm to produce a ready to use biochar production. Product of biochar after pyrolysis was mixed with adhesive organic dopant to earn a shape with a mass of nearly 100 gram for commercial uses. Received product thereafter analyzed by several characterization methods such as heavy elemental de- termination, thermo-gravimetric analysis, Fourier transform infrared spectroscopy and electron para- magnetic resonance spectroscopy for the quality check. Data from these analysis is compared to those of brown coal Aduunchuluun which is originally from the same place as to the bio waste. Heavy elements content in biochar such as silicon, aluminium, sulphur and etc. is significantly less amount in the product compared to the brown coal. TG and DTG analysis on the biochar product has shown total weight loss of 0.87%, in where nearly 26% of moisture release in the temperature interval of 30 − 3000C, 46% of devolatilization in 300 − 6000C and 0.15% of mass loss in combustion reaction in 600 − 7000C. The residue after the thermal processing is few. The main consistent of volatilization are hemicellulose and cellulose parts of the biomass structure. FTIR analysis is analytic method of molecular structure to reveal. Functional groups that give vibra- tions were compared to the those of brown coal. FTIR general spectra of biochar is less intense. Characteristic absorbance bands are hydroxylic stretching vibration of −OH at range 3400 cm−1, stretching C − H at 3000 − 2800 cm−1, breaking O − CH3 at 1460 cm−1 and C − O stretching at 1047 cm−1.
Энэхүү судалгааны ажлаар CVD аргаар Fe-Co/Al2O3 биметалл катализаторыг ашиглан аргон хийн орчинд бутан хийн урвалын хугацаа тогтмол 3 мин хугацаанд 590˚С, 640˚С, 690˚С, 740˚С, 790˚С температурын утгуудад НТНХ -г гарган авч, гарцын хэмжээ температураас хамаарч хэрхэн өөрчлөгдөж байгааг туршилтаар олж тогтоов. Катализаторын бүтэц найрлагын шинж чанарыг EDX анализын үр дүнгээр, морфологи гадаргуун шинж чанарыг SEM, TEM зургаас ажиглаж, дундаж диаметрийг тодорхойлоход 7 нм орчим байв. НТНХ –н морфологи, бүтэц гадаргуун шинж чанарыг SEM, TEM зургаас ажиглаж, дундаж диаметрийг тодорхойлоход ойролцоогоор 14 нм байлаа.
Aluminum-supported iron and cobalt (Fe-Co/Al2O3) bimetallic nano-sized catalyst has been synthesized by the sol-gel method. The average diameter of the Fe-Co/Al2O3 catalyst was measured to be around 7 nm from SEM images. EDX measurements revealed that Fe-Co/Al2O3 consists of 59.98% of Al, 20.00% of Fe, and 20.02% of Co by atomic weight. Multi-walled carbon nanotubes (MWCNT) were prepared using as-synthesized nanocatalyst from a commercial butane gas by the CCVD method at different reaction temperatures. TEM and XRD measurements revealed that Fe-Co/Al2O3 bimetallic nano-sized catalyst is beneficial to fabricate MWCNTs by the CCVD method. The highest yield of MWCNTs was obtained at 690˚C.
Copper-doped ZnO nanoparticles with a dopant concentration varying from 1–7 mol% were synthesized and their structural, magnetic, and photocatalytic properties were studied using XRD, TEM, SQUID magnetometry, EPR, UV-vis spectroscopy, and first-principles methods within the framework of density functional theory (DFT). Structural analysis indicated highly crystalline Cu-doped ZnO nanoparticles with a hexagonal wurtzite structure, irrespective of the dopant concentration. EDX and EPR studies indicated the incorporation of doped Cu2+ ions in the host ZnO lattice. The photocatalytic activities of the Cu-doped ZnO nanoparticles investigated through the degradation of methylene blue demonstrated an enhancement in photocatalytic activity as the degradation rate changed from 9.89 × 10−4 M min−1 to 4.98 × 10−2 M min−1. By the first-principles method, our results indicated that the Cu(3d) orbital was strongly hybridized with the O(2p) state below the valence band maximum (VBM) due to covalent bonding, and the ground states of the Cu-doped ZnO is favorable for the ferromagnetic state by the asymmetry of majority and minority states due to the presence of unpaired electron.
Бид энэхүү ажлаар төмөр ба кобальт агуулсан хөнгөн цагаан суурьтай (Fe-Co/Al2O3) биметал нанокатализатор ашиглан уураас суулгах химийн аргаар (CVD) олон ханат нүүрстөрөгчийн нано хоолойг (НТНХ) гарган авлаа. Ингэхдээ түүний физик, химийн шинж чанарт урвалын температурын нөлөөг судлах зорилгоор олон ханат НТНХ-г 590С, 640С, 690С, 740С болон 790С температурт синтезлэсэн. Гарган авсан НТНХ-н кристалжилтыг рентген бүтцийн анализын аргаар судласан. Рентген дифрактограмд илэрсэн 25.8, 44.1, 45.1, 77.5 өнцгийн утгуудад харгалзах (002), (100), (101), (110) сарнилын хавтгайн пикүүд JCPDS No. 01-0646 стандарт карттай бүрэн тохирч байна. Электрон микроскопын (TEM) хэмжилтээр урвалын температур өсөхөд НТНХ-н ханын тоо өсч, диаметр нэмэгдэж буй зүй тогтол ажиглагдсан. Туршилтын үр дүнгээс дээрх температурын утгуудад харгалзах 1 мг катализаторт ноогдох эцсийн бүтээгдэхүүний хэмжээ 7.68, 12.68, 21.4, 16.56, 14.4 мг буюу 690С-т хамгийн өндөр гарцтай болох нь харагдсан.
Бид энэхүү ажлаар төмөр ба кобальт агуулсан хөнгөн цагаан суурьтай (Fe-Co/Al2O3) биметал нанокатализатор ашиглан уураас суулгах химийн аргаар (CVD) олон ханат нүүрстөрөгчийн нано хоолойг (НТНХ) гарган авлаа. Ингэхдээ түүний физик, химийн шинж чанарт урвалын температурын нөлөөг судлах зорилгоор олон ханат НТНХ-г 590С, 640С, 690С, 740С болон 790С температурт синтезлэсэн. Гарган авсан НТНХ-н кристалжилтыг рентген бүтцийн анализын аргаар судласан. Рентген дифрактограмд илэрсэн 25.8, 44.1, 45.1, 77.5 өнцгийн утгуудад харгалзах (002), (100), (101), (110) сарнилын хавтгайн пикүүд JCPDS No. 01-0646 стандарт карттай бүрэн тохирч байна. Электрон микроскопын (TEM) хэмжилтээр урвалын температур өсөхөд НТНХ-н ханын тоо өсч, диаметр нэмэгдэж буй зүй тогтол ажиглагдсан. Туршилтын үр дүнгээс дээрх температурын утгуудад харгалзах 1 мг катализаторт ноогдох эцсийн бүтээгдэхүүний хэмжээ 7.68, 12.68, 21.4, 16.56, 14.4 мг буюу 690С-т хамгийн өндөр гарцтай болох нь харагдсан.
Энэхүү судалгааны ажлаар CVD аргаар Fe-Co/Al2O3 биметалл катализаторыг ашиглан аргон хийн орчинд бутан хийн урвалын хугацаа тогтмол 3 мин хугацаанд 590˚С, 640˚С, 690˚С, 740˚С, 790˚С температурын утгуудад НТНХ -г гарган авч, гарцын хэмжээ температураас хамаарч хэрхэн өөрчлөгдөж байгааг туршилтаар олж тогтоов. Катализаторын бүтэц найрлагын шинж чанарыг EDX анализын үр дүнгээр, морфологи гадаргуун шинж чанарыг SEM, TEM зургаас ажиглаж, дундаж диаметрийг тодорхойлоход 7 нм орчим байв. НТНХ –н морфологи, бүтэц гадаргуун шинж чанарыг SEM, TEM зургаас ажиглаж, дундаж диаметрийг тодорхойлоход ойролцоогоор 14 нм байлаа.
Al-supported Fe-Co (Fe- Co/Al2O3) bimetallic nanocatalyst with an average size of 10 nm was synthesized by sol-gel process. Multiwalled carbon nanotubes (MWCNTs) were fabricated through a chemical vapor deposition method at various reaction temperature. SEM-EDX, TEM, XRD and FT-IR techniques were utilized to characterize the physical and chemical properties of as-synthesized samples. SEM-EDX experiment from the nanocatalyst shows the weight ratio of Al, Fe and Co metals in the sample roughly 1:1:1.
Abstract. The novel bicycloamino acid, 1−carboxyl−4−amino−2−aza−3−oxo−[2.2.2] bicyclooctane was synthesized and its physical characteristics have been compared to those predicted using quantum chemical calculations. The crystal structure of novel compound was determined by X-ray diffraction measurements at room temperature. Unit cell is monoclinic, with space group P 21/n (14) and a = 5.8587(6) Ǻ, b = 11.2454(16) Ǻ, c = 13.9723(16) Ǻ, β=97.840(6)°, Z = 2. Refinement was performed using all 1598 reflections with R = 0.4085 and wR = 0.6024. Theoretical calculation of full optimization and atomic net charge, and frontier orbital energies of the title compound was carried out at the B3LYP/6−31G(d,p) level. The NMR chemical shielding tensors and vibrational frequencies were calculated with B3LYP/6-311+G(2d, p)− level in which were close values and similar spectrum structures with experimental results and used to interpret the experimental measurements.
Spherical silver nanoparticles (AgNSP) were synthesized by citrate reduction method, with an average diameter of 50 nm. Seed-mediated growth method has been conducted to prepare a silver nanorods (AgNR). The characteristic surface-plasmon resonance (SPR) peak of AgNSP was observed at 419 nm in UV-Vis absorption spectra, while a transverse and longitudinal peaks of AgNR were detected at 419 nm and 571 nm, respectively. Comparison study on catalytic activity of as-synthesized silver nanomaterials was performed by means of the reduction rate of 2,4-dinitrophenol to 2,4-aminophenol.
The tendency of use of coals under the restrictions of environmental safety demands a more detailed understanding of its structure for its various processing. Particularly, processing of brown coals is the most important for us (Mongolia) in the near future, since the brown coal is the most abundant (several hundred million tonnes) and approachable (more than 200 coal occurrences) resource in the country. Selected coal owns low degree of carbon containment. Additionally, oxygen and several trace elements content can be determined by scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS). The analysis indicates dominations of elements such as silicon, calcium, aluminium and iron in the raw coal. By using the SEM results the Fourier transform infrared (FTIR) bands particularly, long wave region, are identified. Two extraction products are prepared in the refluxing processing of raw coal in solvents such as pyridine and ionic liquid (1-butyl-3-methilimidazolium chloride). Moreover, separated from the extractions, the insoluble coal residues washed with methanol, were analyzed as well. Structural features are determined in the brown coal extraction products after the processing with the solvents such as pyridine and ionic liquid (1-butyl-3-methilimidazolium chloride). Coal extraction characterizations thereafter, are compared to its raw coal functional groups using by FTIR spectroscopy. The difference in spectra is observed even for the used solvents. For example, an extraction FTIR spectrum in the pyridine treatment presents changes mostly in the long wave of the vibrational region. Short wave bands at 3400 and 3000-2800 cm-1 are the least affected under the pyridine processing. In contrast, long wave bands were vanished or weakened by intensity, essentially, the mineral bands in 600-400 cm-1 region of wave number. An intensity of whole infrared spectrum is low powered in the pyridine used solvent case, but an opposite way for the ionic liquid treatment. In the ionic liquid processing the spectrum is involved wholly, means the short and long wave regions of vibration. Ionic liquid and coal interaction calls stretching bond around 3000-2800 cm-1 to be affected and a blue shift of C-O bands at 1600 cm-1 and of minerals at 600-400 cm-1. It should be noted that the ionic liquid is still a powerful solvent in the meaning of solving insoluble material like coal. Insoluble coal residues are either analyzed by FTIR spectroscopy and compared to the raw coal infrared spectrum. In both pyridine and ionic liquid cases the residues were well washable from the solvent by methanol. FTIR spectra proves that in both case infrared spectra were renewable by means the original functional groups are similar as its raw coal.
This work reports a doping effectiveness of copper (Cu) doped zinc oxide (ZnO) nanoparticles synthesized through surfactant free organic phase route. The structural and photocatalytic properties were studied TEM, UV-vis spectroscopy as well as the antibacterial activity was tested on Escherichia coli (E. coli ATCC 25922) and Staphylococcus aureus (S. aureus ATCC 25923) bacteria by broth dilution method and nanoparticle free solutions were used in antimicrobial tests against E. coli and S. aureus. The band gap of the nanoparticles was decreased from 3.32 to 3.28 eV depending on the doping concentration. Photocatalytic degradation of MB dye reaction rate was changed from 1.2x10-4M/min to 10.9x10-3M/min. These results indicate that interactions between sp and d orbitals of host matrix (ZnO) and dopant (Cu), respectively, lead to conduction band and valence band narrowed also Cu ions substituting in ZnO matrix and increase the separation of photogenerated electron-hole pairs. The synthesized Zn1-xCuxO nanoparticles showed increasing inhibitory effects on the growth of each bacteria type as the concentrations of Cu doping increased. Significant antibacterial inhibition founded from 7M% Cu doped ZnO nanoparticles for 98.9% and 97.4% for E. coli and S. aureus, respectively.
Энэхүү судалгааны ажлаар хөнгөн цагаан суурьтай биметалл (Fe-Co/Al2O3) катализаторыг Печини аргаар гарган авсан. Катализаторын морфологи бүтэц, элементийн агуулгыг SEM-EDX хэмжилтээр тодорхойлсон. Туршилтын үр дүн катализаторт хөнгөн цагаан 7.5%, төмөр 41.7%, кобальт 50.7%-тай агуулагдаж байгааг тогтоосон. Fe-Co/Al2O3 катализатор нь CVD аргаар нүүрстөрөгчийн нанохоолой гарган авахад тохиромжтой бөгөөд үр ашигтай болох нь туршилтаар батлагдсан.
Alumina-supported Fe Co catalyst was synthesized by Pechini method inwhich Fe as the corecatalyst,Co as the co catalyst, and Al2O3 as the catalyst carrier. To prepare catalysts, appropriate amount of ferricnitrate, cobalt nitrate and aluminum nitrate were dissolved under vigorous stiriing in a solution containing ethylene glycol and citric acid at 95°C. Then, the sample went under heat treatment at various temperature after complete evaporation of solute molecules. Here, we prepared four different catalyst samples depending on the temperature of heat treatment in order to determine an optimal conditions to synthesize metal catalyst for carbon nanotubes via CVD method. The active component of bimetal Fe-Co catalysts (Fe:Co2:1) is Fe-Co alloy nanoparticles. Tubes produced using the bimetal catalysts have a high degree of structural perfection and narrow diameter distribution. Fe-Co catalyst on Al2O3 and catalyzer precursor for CNT fabrication by chemical vapor deposition method in argon+butan atmosphere at 800°C for 20min.
Colloidal dispersions of spherical silver nanoparticles (AgNPs) have been synthesized by a citrate reduction method in which sodium citrate is utilized as both of reducing and stabilizing agents. Catalytic properties of as-synthesized AgNPs were examined using the reduction of 2,4-dinitrophenol (2,4-DNP) by sodium-borohydride. Experimental results revealed that the citrate-stabilized AgNPs is a very efficient catalysts for the degradation of 2,4-DNP.
In this work transition metal copper (Cu) doped Zn1-xCuxO nanoparticles were synthesized by different doping concentration of Cu (x=1, 3, 5 and 7M %) through surfactant free benzyl alcohol route method in which zinc acetate, zinc acetylacetonate and copper acetate were selected as precursors. Crystal and structural analysis of all synthesized nanoparticles were determined by XRD and FT-IR. The XRD analysis demonstrated aff reflection peals with hexagonal wurtzite structure. The morphology and elemental analysis determined by TEM-EDX, TEM/STEM. Photocatalytic and antibacterial activity were studied by effectiveness of doping concentration. The methylene blue (MB) dye was used to investigate the photocatalytic experiment. 5M% Cu doped ZnO particles were showed high degradation efficiency. The antibacterial activity was tested in gram negative bacteria, E.Coli and gram positive S. Aureus dilution method. After the doping significant antibacterial inhibition founded from 7M% Cu doped ZnO NPs for 98.9% and 97.4% for E. coli and S. aureus, respectively. Keywords: Zinc oxide nanoparticles, Rhodamine 6G, photocatalytic activity, photo degradation, antibacterial activity, Escherichia Coli, Sataphylcoccus Aureus. Acknowledgements: This work is supported by the Asian Research Center Project (2018-3573).
Enhancing the chemical and physical properties of metal oxide nanoparticles (NPs) by doping with transition metals have been received great attention due to their variety of applications such as environmental pollutant issues. In this work, we synthesized the copper-doped ZnO NPs (Zn1-xCuxO) through surfactant free method to improve its photocatalytic activity. Structural and morphological characterizations of the asprepared NPs performed on XRD, TEM, STEM and EDX spectroscopy have been showed that the obtained nanoparticles were crystalline particles with all reflections matching to wurtzite. Methylene blue (MB) was involved in order to compare photocatalytic activity of the Cu doped and non-doped ZnO NPs. Experimental results showed photocatalytic activity of ZnO NPs was depending on dopant concentration
Кальцийн карбонатийн микро болон нанохэмжээст төрөл бүрийн бүтцүүд нь сүүлийн жилүүдэд судлаачдын анхаарлыг ихээр татсаар байна. Кальцийн карбонат (CaCO3)-ийн нанобөөм нь хорвуу чанар багатай, биологийн орчинд тэсвэртэй, хувийн гадаргуун талбай ихтэй (сүвэрхэг шинж чанартай) зэрэг олон давуу талтай учир эмийн үндсэн найрлаганд ашиглаж болохоос гадна хорт хавдарын эсийг эмчлэх зорилгоор эмийг зөөвөрлөгч болгон ашиглах боломжтой. Кальцийн карбонатийн нанобөөмсийг полимерик материалд хольцолж өгснөөр тэдгээрийн гадны нөлөөлөлийн эсэргүүцэх чадвар, уян харимхай шинж чанаруудыг илүү сайжруулдаг ба үйлдвэрлэлийн өртөгийг бууруулж өгдөг. CaCl2 (кальцийн хлорид) болон Na2CO3 (натрийн карбонат) тус бодисуудыг тодорхой концентраци бүхий усан уусмал хэлбэрт оруулж, хооронд нь холих үед, CaCO3(кальцийн карбонат) үүсч NaCl (натрийн хлорид) давхар үүснэ. CaCl2 + Na2CO3 → CaCO3 ↓ +2NaCl (1) Их хэмжээгээр үйлдвэрлэх тохиолдолд техникийн хувьд нэгэн төрлийн урвалын орчинг бий болгоход төвөгтэй. Урвалын орчин нь урвалжын концентраци, холих хурд, pH, температур гэх мэт олон хүчин зүйлсээс хамаардаг. Туршилтын үр дүнд бий болсон бүтээгдэхүүн кальцийн карбонат нь 3 өөр төрлийн хэлбэртэй. Үүнд: кальцит, ватерит, аргонит гэсэн үндсэн фазууд байх ба дангаараа болон холимог хэлбэрээр оршин байна. Их хэмжээгээр үйлдвэрлэх зорилготой кальцийн карбонатийн нанобөөмсийг гарган авах өөр нэг арга нь механик - химийн боловсруулалтын арга юм. Энэхүү арга нь CaCl2 болон Na2CO3 бодисуудыг хуурай нунтаг хэлбэрээр нь хольсон хольцыг бөмбөгөн эсвэл таталцлын тээрэмд тээрэмдэж эцсийн бүтээгдэхүүнийг гарган авдаг. Үүссэн бүтээгдэхүүн нь хатуу NaCl (давсан)-д бие даасан нанобөөмсүүд шигтгэгдэж үүсдэг. Хэдийгээр энэхүү арга нь харьцангуй энгийн цөөн тооны параметрүүдээс хамаарах боловч тээрэмдэх, дулааны боловсруулалт хийх, бүтээгдэхүүнээс давсыг ионжуулсан усаар угааж салган авч, хатаах зэрэг ажлууд нь нилээд эрчим хүч шаардсан, эцсийн бүтээгдэхүүн гарган авах шат дамжлага ихтэй зэрэг сул талтай. Өөр нэг арга нь микро уусмалын орчинд шохойн уусмалыг карбонатжуулах замаар өндөр даралттай нэгэн төрлийн орчинг ашиглаж урвал явуулж тунадасжуулж гарган авах арга юм. Тус арга нь эдийн засгийн хувьд үр ашиг бага тул үйлдвэрлэлд өргөн хэрэглэгддэггүй. Бид энэхүү ажилд CaCO3 нанобөөмсийг массаар үйлдвэрлэх боломжтой аэрозолийн болон тунадасжуулах аргуудыг туршив. Соронзон нанонунтгийг тэдгээрийн өвөрмөц физик химийн шинж чанарт үндэслэн төрөл бүрийн биоанагаахын хэрэглээ болох соронзон резонанст томографи (MRI), микробиологийн соронзон тусгаарлагч, хүрээлэн буй орчны бохирдол зэрэгт өргөнөөр ашиглах бүрэн боломжтой юм. Соронзон нанонунтгууд синтезлэсний дараа хялбархан аггломерацид орж бөөгнөрдөг. Гадаргуугийн бүрэлт нь энэхүү асуудлыг үр ашигтайгаар шийдвэрлэх боломжийг олгодог. Энэхүү ажлын зорилго нь кальцийн карбонат (CaCO3) болон төмрийн оксид (Fe3O4)–ын микро болон нано хэмжээт бүтцүүдийг өөрсдийн лабораторийн нөхцөлд гарган авч, тэдгээрийн физик болон химийн шинж чанарыг судлахад чиглэсэн болно
Энэхүү ажлаар кальцийн карбонат (CaCO3) болон төмрийн оксид (Fe3O4)–ын микро болон нано хэмжээт бүтцүүдийг гарган авлаа. Тундасжуулах болон аэрозолийн аргаар гарган авах авсан дээжид CaCO3-н кальцит, ватирит бүтцүүд байгаа нь оптик болон электрон микроскопийн хэмжилтээр ажилглагдсан. Туршилтын үр дүн микро хэмжээтэй CaCO3-н бөөмсийг дээрх хоёр аргаар гарган авах боломжтойг харуулав. Электроны микроскопийн зургаас төмрийн оксидын нанонунтгийн хэмжээ ойролцоогоо 8 нм байгаа нь тогтоогдов. Мөн нил улаан туяаны шингээлтийн спектрт 586 см-1 долгион тоонд Fe-O-н валентийн хэлбэлзэл илэрсэн нь төмрийн оксидын нанонунтгийг амжилттай гарган авсныг баталж байна.
Энэхүү судалгааны ажлаар шилжилтийн метал зэсээр допинг хийсэн цайрын оксид (Zn 1-x Cu x O)-ын нанопартиклыг усан биш органик фазын аргаар гарган авсан. Бүтцийн болон морфологийн шинж чанарыг рентген дифрактометр (XRD), нил улаан туяаны спектроскоп (FTIR) тус тус ашиглан тодорхойлсон. Гарган авсан нанопартикл нь гексагональ вюрцит бүтэцтэй болох нь батлагдсан. Органик будагч бодис родамин 6 жи-г сонгон авч фотокаталитик идэвхийг зэсийн концетрациас хамааруулан судалсан. Туршилтын үр дүнгээс допингийн концентраци нэмэгдхэд фотокаталитик идэвхи сайжирсан.
Applying semiconductor materials for photocatalytic degradation of organic compounds has found more efficiency, rapid oxidation and not bring secondary environmental pollution [1]. Photcatalytic reaction takes place at the surface of catalyst. The photocatalyst (semiconducting material) absorbs light having energy equal to or stronger than its band gap energy, which induces the hole-and-electron pairs for the formation of OH free-radicals to oxidize the organic dye molecules [2]. Nanoparticles semiconductor materials such as TiO2, ZnS, ZnO, CdS and Fe2O3 are potential use in photocatalysis has particularly aroused great interest and optical properties. Among these materials ZnO has been extensive attention due to its suitable, low cost and non-toxic [3]. Strategies to improve photodegradation efficiency of ZnO photocatalyst doping with transition metal or noble metal ions may produce crystal defects and influence the optical properties of ZnO and that doped metal ions can reduces the electron-hole pair recombination which were induced during the light illumination and enhancing the charge separation between electrons and holes [4]. Nowadays various transition metal as cationic dopant like Cu, Ag, Mn, Ni, Al and Co has been used due to their properties and resulting enhancement even depend on synthesis method and dopant type. In this work, we synthesized the copper-doped ZnO NPs (Zn1-xCuxO) through surfactant free nonhydrolytic organic phase method in different dopant concentration to improve its photocatalytic activity. From the XRD data, the crystallinity of the doped samples is high as for the undoped amples and relative intensities of first three peaks remained same after doping suggesting no change in morphology. However, the appearance of small shoulder at around 2θ=43 and 50, suggesting that trace amount of impurity phase could be present in the doped samples. Photocatalytic activities for the degradation of R6G aqueous solutions using Cu-doped ZnO nanorods were studied with UV-vis spectrometry. As seen from the presented experimental data, the activity of Cu-doped ZnO for the photocatalytic dye degradation increases for Cu concentrations within the range of 0.0−3 mol%, and reaches a maximal value at a Cu concentration of 3-4mole %, and then significantly decreases at higher Cu concentrations. Further studies is ongoing catalytic and antibacterial activity. Rhodamine 6G was involved in order to compare photocatalytic activity of the doped and non-doped ZnO NPs. The photocatalytic activity of Zn1-xCuxO NPs was evaluated under UV irradiation at room temperature using the UV-lamp (365 nm wavelength). In a typical process, 5 mg of photocatalyst was added to 20 mL of aqueous solution containing Rhodamine 6G dye (R6G) with a concentration of 6.25 µM and each absorption spectrum was recorded in every 10 minutes. X axis is time and Y axis is normalized absorbance. Plot shows that R6G dye is very stable in ambient condition. Whereas, when using ZnO NPs catalyst degradation efficiency was much higher than without catalyst.
ZnO nanoparticles (ZnO NPs) were synthesized through surfactant free non-hydrolytic organic phase method in which zinc acetate and zinc acetylacetonate were selected as precursors. Structural and size analysis of the as-prepared nanoparticles performed on X-ray diffractometer, transmission electron microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy showed that the obtained nanoparticles were crystalline particles with all reflections matching to wurtzite. TEM images revealed that ZnO NPs from synthesis in which zinc acetate involved as precursor had a shape of sphere while zinc acetylacetonate resulted in rod-shaped nanoparticles. Reaction rates from catalytic activity test performed on Methylene Blue dye (MB) were found to be 2.99×10-2 min-1 and 1.98×10-2 min-1 for spherical and rod-shaped ZnO NPs, respectively. Antibacterial activity experiments shows rod-shaped ZnO NPs almost completely (99.75%) inhibited the growth of Escherichia Coli while only around 6.5% was survived after treatment of spherical ZnO NPs under same conditions
In this study, colloidal metal nanoparticles have been prepared by the wet-chemical synthesis method. Gold and silver nanoparticles with approximate sphere shape were synthesized through the citrate-reduction method. The colloidal metal nanoparticles were characterized by using UV-vis absorption spectroscopy, photon cross-correlation spectroscopy (PCCS) and transmission electron microscope (TEM). Catalytic activities of the metal nanoparticles were investigated through reduction of 2,4-dinitrophenol to 2,4-diaminophenol in the presence of NaBH4 at room temperature. Both gold and silver nanoparticles showed an excellent catalytic activity
