The novel zirconium oxide, nickel oxide and zinc oxide nanoparticles supported activated carbons（Zr-AC, Ni-AC, Zn-AC） were successfully fabricated through microwave irradiation method. The synthesized nanoparticles ...The novel zirconium oxide, nickel oxide and zinc oxide nanoparticles supported activated carbons（Zr-AC, Ni-AC, Zn-AC） were successfully fabricated through microwave irradiation method. The synthesized nanoparticles were characterized using XRD, HR-SEM, XPS and BET. The optical properties of Zr-AC, Ni-AC and Zn-AC composites were investigated using UV–Vis diffuse reflectance spectroscopy. The photocatalytic efficiency was verified in the degradation of textile dyeing wastewater（TDW） in UV light irradiation. The chemical oxygen demand（COD） of TDW was observed at regular intervals to calculate the removal rate of COD. Zn-AC composites showed impressive photocatalytic enrichment, which can be ascribed to the enhanced absorbance in the UV light region, the effective adsorptive capacity to dye molecules, the assisted charge transfer and the inhibited recombination of electron-hole pairs. The maximum TDW degradation（82% COD removal） was achieved with Zn-AC. A possible synergy mechanism on the surface of Zn-AC was also designed. Zn-AC could be reused five times without exceptional loss of its activity.展开更多
Cu-Ni alloy nanoparticles were prepared by a microwave combustion method with the molar ratios of CU2＋ to Ni2＋ as 3：7, 4：6, 5：5, 6：4 and 7：3. The as-prepared samples were characterized by XRD, HR-SEM, EDX and V...Cu-Ni alloy nanoparticles were prepared by a microwave combustion method with the molar ratios of CU2＋ to Ni2＋ as 3：7, 4：6, 5：5, 6：4 and 7：3. The as-prepared samples were characterized by XRD, HR-SEM, EDX and VSM. XRD and EDX analyses suggest the formation of pure alloy powders. The average crystallite sizes were found to be in the range of 21.56-33.25 nm. HR-SEM images show the clustered/agglomerated particle-like morphology structure. VSM results reveal that for low Ni content （CusNis, Cu6Ni4 and Cu7Ni3）, the system shows paramagnetic behaviors, whereas for high Ni content （Cu3Ni7 and Cu4Ni6）, it becomes ferromagnetic.展开更多
Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, microwave-assisted ure...Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, microwave-assisted urea–nitrate combustion synthesis, without the use of organic solvents or surfactants. The prepared samples were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The optical absorption of Zn O extended into the visible region after CuO loading. The photocatalytic activities of ZnO, CuO, and the coupled oxides were evaluated based on photodegradation of 2,4-dichlorophenol under visible-light irradiation. The coupled metal oxide Zn2Cu showed the best photocatalytic activity; this was mainly attributed to the extended photoresponsive range and the increased charge separation rate in the nanocomposite. The photocatalytic degradation process obeyed pseudo-first-order kinetics. The results suggest that the coupled metal oxide Zn2Cu has potential applications as an efficient catalytic material with high efficiency and recyclability for the photocatalytic degradation of organic pollutants in aqueous solution under visible-light irradiation.展开更多
Various nanosized zinc aluminate(ZnAl2O4) samples were prepared by a conventional and a mi- crowave method both with and without using Opuntia dilenii haw plant extract,and were charac- terized by X-ray diffraction(XR...Various nanosized zinc aluminate(ZnAl2O4) samples were prepared by a conventional and a mi- crowave method both with and without using Opuntia dilenii haw plant extract,and were charac- terized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),high resolution scanning electron microscopy(HRSEM),energy dispersion scanning(EDX),temperature dependent conductance measurements, thermoelectric power measurements, ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy,and photoluminescence spectroscopy.The formation of a pure ZnAl2O4 phase was confirmed by XRD and FT-IR.A change in morphology from nanosized plates to nanosized sheets with,respectively,the conventional and microwave heating methods was clearly shown by HRSEM.UV-Vis diffusion reflectance spectroscopy measured the band gaps of ZnAl2O4 nanosized plates and nanosized sheets as 3.5 and 3.9 eV,respectively.The synthesized ZnAl2O4 was single crystalline and has three photoluminescence emissions at 482,528,and 540 nm.ZnAl2O4 nanosized sheets prepared by the microwave method showed higher catalytic activity for the oxida- tion of benzyl alcohol(85% conversion) than ZnAl2O4 nanosized plates prepared by the convention- al method(60% conversion).展开更多
A novel self-assembled pure and Mg doped ZnO nano-particles （NPs） were successfully synthesized by a simple low temperature co-precipitation method. The prepared photocatalysts were characterized by X-ray diffractio...A novel self-assembled pure and Mg doped ZnO nano-particles （NPs） were successfully synthesized by a simple low temperature co-precipitation method. The prepared photocatalysts were characterized by X-ray diffraction, high resolution scanning electron mi- croscopy, high resolution transmission electron microscopy, diffuse reflectance spectroscopy and photoluminescence （PL） spectroscopy. The results indicated that the prepared photocatalysts showed high crystallinity with a uniform size distribution of the NPs. The degradation of cholorphenols is highly mandatory in today＇s scenario as they are affecting the environment adversely. Thus, the photocatalytic degradation of 4-chlorophenol （4-CP）, a potent endocrine disrupting chemical in aqueous medium was investigated by both pure and Mg-doped ZnO NPs under UV-light irradiation in the present study. The influence of the Mg content on the structure, morphology, PL character and photocatalytic activity of ZnO NPs were investigated systematically. Furthermore,the effect of different parameters such as 4-CP concentration, photocatalyst amount, pH and UV-light wavelength on the resulting photocatalytic activity was investigated.展开更多
基金financial support rendered by the Salesians of Don BoscoDimapur Province+1 种基金NagalandNorth East India
文摘The novel zirconium oxide, nickel oxide and zinc oxide nanoparticles supported activated carbons（Zr-AC, Ni-AC, Zn-AC） were successfully fabricated through microwave irradiation method. The synthesized nanoparticles were characterized using XRD, HR-SEM, XPS and BET. The optical properties of Zr-AC, Ni-AC and Zn-AC composites were investigated using UV–Vis diffuse reflectance spectroscopy. The photocatalytic efficiency was verified in the degradation of textile dyeing wastewater（TDW） in UV light irradiation. The chemical oxygen demand（COD） of TDW was observed at regular intervals to calculate the removal rate of COD. Zn-AC composites showed impressive photocatalytic enrichment, which can be ascribed to the enhanced absorbance in the UV light region, the effective adsorptive capacity to dye molecules, the assisted charge transfer and the inhibited recombination of electron-hole pairs. The maximum TDW degradation（82% COD removal） was achieved with Zn-AC. A possible synergy mechanism on the surface of Zn-AC was also designed. Zn-AC could be reused five times without exceptional loss of its activity.
文摘Cu-Ni alloy nanoparticles were prepared by a microwave combustion method with the molar ratios of CU2＋ to Ni2＋ as 3：7, 4：6, 5：5, 6：4 and 7：3. The as-prepared samples were characterized by XRD, HR-SEM, EDX and VSM. XRD and EDX analyses suggest the formation of pure alloy powders. The average crystallite sizes were found to be in the range of 21.56-33.25 nm. HR-SEM images show the clustered/agglomerated particle-like morphology structure. VSM results reveal that for low Ni content （CusNis, Cu6Ni4 and Cu7Ni3）, the system shows paramagnetic behaviors, whereas for high Ni content （Cu3Ni7 and Cu4Ni6）, it becomes ferromagnetic.
文摘Nanostructured ZnO and CuO, and coupled oxides, i.e., ZnCu, Zn2Cu, and ZnCu2, with ZnO:CuO molar ratios of 1:1, 2:1, and 1:2, respectively, were successfully prepared through a simple, one-step, microwave-assisted urea–nitrate combustion synthesis, without the use of organic solvents or surfactants. The prepared samples were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The optical absorption of Zn O extended into the visible region after CuO loading. The photocatalytic activities of ZnO, CuO, and the coupled oxides were evaluated based on photodegradation of 2,4-dichlorophenol under visible-light irradiation. The coupled metal oxide Zn2Cu showed the best photocatalytic activity; this was mainly attributed to the extended photoresponsive range and the increased charge separation rate in the nanocomposite. The photocatalytic degradation process obeyed pseudo-first-order kinetics. The results suggest that the coupled metal oxide Zn2Cu has potential applications as an efficient catalytic material with high efficiency and recyclability for the photocatalytic degradation of organic pollutants in aqueous solution under visible-light irradiation.
文摘Various nanosized zinc aluminate(ZnAl2O4) samples were prepared by a conventional and a mi- crowave method both with and without using Opuntia dilenii haw plant extract,and were charac- terized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),high resolution scanning electron microscopy(HRSEM),energy dispersion scanning(EDX),temperature dependent conductance measurements, thermoelectric power measurements, ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy,and photoluminescence spectroscopy.The formation of a pure ZnAl2O4 phase was confirmed by XRD and FT-IR.A change in morphology from nanosized plates to nanosized sheets with,respectively,the conventional and microwave heating methods was clearly shown by HRSEM.UV-Vis diffusion reflectance spectroscopy measured the band gaps of ZnAl2O4 nanosized plates and nanosized sheets as 3.5 and 3.9 eV,respectively.The synthesized ZnAl2O4 was single crystalline and has three photoluminescence emissions at 482,528,and 540 nm.ZnAl2O4 nanosized sheets prepared by the microwave method showed higher catalytic activity for the oxida- tion of benzyl alcohol(85% conversion) than ZnAl2O4 nanosized plates prepared by the convention- al method(60% conversion).
基金the financial support rendered by University Grants Commission(UGC)(Ref.F.No.38-118/2009(SR)),New Delhi
文摘A novel self-assembled pure and Mg doped ZnO nano-particles （NPs） were successfully synthesized by a simple low temperature co-precipitation method. The prepared photocatalysts were characterized by X-ray diffraction, high resolution scanning electron mi- croscopy, high resolution transmission electron microscopy, diffuse reflectance spectroscopy and photoluminescence （PL） spectroscopy. The results indicated that the prepared photocatalysts showed high crystallinity with a uniform size distribution of the NPs. The degradation of cholorphenols is highly mandatory in today＇s scenario as they are affecting the environment adversely. Thus, the photocatalytic degradation of 4-chlorophenol （4-CP）, a potent endocrine disrupting chemical in aqueous medium was investigated by both pure and Mg-doped ZnO NPs under UV-light irradiation in the present study. The influence of the Mg content on the structure, morphology, PL character and photocatalytic activity of ZnO NPs were investigated systematically. Furthermore,the effect of different parameters such as 4-CP concentration, photocatalyst amount, pH and UV-light wavelength on the resulting photocatalytic activity was investigated.
