In this paper, we have demonstrated a facile and low-cost synthesis of the ZnO/CuO nanocomposites by two-step hydrothermal methods. The photocatalytic properties of the as-synthesized ZnO/CuO nanocomposites have been ...In this paper, we have demonstrated a facile and low-cost synthesis of the ZnO/CuO nanocomposites by two-step hydrothermal methods. The photocatalytic properties of the as-synthesized ZnO/CuO nanocomposites have been evaluated by the photodegradation of methylene blue(MB) and methyleneorange(MO) under UV irradiation. Experimental results show that MB and MO can be degraded completely within 15 and 25 min by the ZnO/CuO nanocomposites and its photodegradation rate is 6 times faster than that of pure ZnO. This enhanced photocatalytic activity can be ascribed to the low recombination probability of photo-induced carriers due to the efficient charge transfer in the nanocomposites. The as-synthesized ZnO/CuO nanocomposite may be a promising candidate for dye photodegradation of wastewaters.展开更多
An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horiz...An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horizontal tube furnace on a 40 nm TiO_(2)thin film deposited on a p-type Si(100)substrate.The CuO–TiO_(2)/TiO_(2)/p-Si(100)devices exhibited excellent rectification characteristics under dark and individual photoillumination conditions.The devices showed remarkable photo-response under broadband(300–1100 nm)light illumination at zero bias voltage,indicating the achievement of highly sensitive self-powered photodetectors at visible and near-infrared light illuminations.The maximum response of the devices is observed at 300 nm for an illumination power of 10 W.The response and recovery times were calculated as 86 ms and 78 ms,respectively.Moreover,under a small bias,the devices showed a prompt binary response by altering the current from positive to negative under illumination conditions.The main reason behind this binary response is the low turn-on voltage and photovoltaic characteristics of the devices.Under illumination conditions,the generation of photocurrent is due to the separation of photogenerated electron-hole pairs within the built-in electric field at the CuO–TiO_(2)/TiO_(2)interface.These characteristics make the CuO–TiO_(2)/TiO_(2)broadband photodetectors suitable for applications that require high response speeds and self-sufficient functionality.展开更多
OBJECTIVE Zn-doped CuO nanocomposites(nZn-CuO NPs) are novel nanoparticles synthesized by sonochemical method.This study aimed to further investigate the antitumor effects and mechanism of nZn-CuO NPs,as well as the e...OBJECTIVE Zn-doped CuO nanocomposites(nZn-CuO NPs) are novel nanoparticles synthesized by sonochemical method.This study aimed to further investigate the antitumor effects and mechanism of nZn-CuO NPs,as well as the exact mechanism of reactive oxygen species(ROS) on nZn-CuO NPs-induced death using N-acetylcysteine(NAC).METHODS The antitumor effects of nZn-CuO NPs were evaluated by MTS assay and orthotopic transplantation tumor model in nude mice.The effects of nZn-CuO NPs with or without NAC on ROS production,DNA damage,apoptosis,mitochondrial damage,autophagy,lysosome impairment,and ER and Golgi stress were determined.Also,western blot was used to detect apoptosis and autophagy related proteins,as well as NF-κB pathway related proteins.RESULTS nZn-CuO NPs significantly inhibit tumor growth both in vitro and in vivo.nZn-CuO NPs were able to cause cytotoxicity,ROS production,DAN damage mitochondrial damage,apoptosis,and autophagy,and NAC can attenuate them.Further studies showed that nZn-CuO NPs induced changes of apoptosis,autophagy and NF-κB pathway related proteins,and NAC can restore them.CONCLUSION Overall,our data demonstrated that nZn-CuO NPs could inhibit tumor growth both in vitro and in vivo by ROS-dependent regulation of apoptosis and autophagy,which might be cross-linked by NF-κB pathways.展开更多
CuO·SnO2 Nanocomposite powders were prepared by solid state reaction from Cu(NO3)2·3H2O, SnCl4·5H2O with NaOH at low temperature. The crystal form, particle size and morphology of the material were char...CuO·SnO2 Nanocomposite powders were prepared by solid state reaction from Cu(NO3)2·3H2O, SnCl4·5H2O with NaOH at low temperature. The crystal form, particle size and morphology of the material were characterized by XRD, TEM, FTIR, SEM-EDS and XPS. The results showed that CuO·SnO2 nanocomposite was composed of CuO with monoclinic crystalline structure and SnO2 with tetragonal crystalline structure. The average particle size of the CuO·SnO2 nanocomposite was about 10 nm.展开更多
The main purpose of this work was the modification of NaX nanozeolite using copper oxide nanoparticles and various monovalent cations such as K^+, Cs^+, and Ag^+in order to make the negatively charged zeolite surface ...The main purpose of this work was the modification of NaX nanozeolite using copper oxide nanoparticles and various monovalent cations such as K^+, Cs^+, and Ag^+in order to make the negatively charged zeolite surface accessible for anionic forms of uranium which are the most dominant species of uranium in the contaminated radioactive waters at natural p H. Various methods such as the X-ray fluorescence(XRF), X-ray powder diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FT-IR), and atomic absorption spectroscopy(AAS) were used to characterize the final synthesized absorbents. Batch technique was used to study the adsorption behavior of uranium ions from polluted drinking water by Na X nanozeolite and its modified forms. In order to better understand the performance of them, the results were compared with those that were obtained for synthesizing bulk NaX zeolite and Na-form of clinoptilolite natural zeolite. Preliminary results indicated that uranium sorption increased as the loading level of CuO nanoparticles on NaX nanozeolite increased from 2.1 wt% to 11.2 wt%. In addition,from the obtained data, an increase in uranium removal efficiency resulted as charge/ionic radius ratio of exchanged cation decreased. Also, the effect of contact time, solid–liquid ratio, initial concentration and temperature on the adsorption process was studied. It is worth mentioning that, in this study, the sorption of uranium was performed under natural conditions of pH and the presence of competing cations and anions which are available in drinking waters.展开更多
We report experimental and mechanistic understanding of methanol oxidation to produce methyl formate using CuO/Ti02-spindle composite as a promising photocatalyst under mild conditions with over 97%conversion and 83%s...We report experimental and mechanistic understanding of methanol oxidation to produce methyl formate using CuO/Ti02-spindle composite as a promising photocatalyst under mild conditions with over 97%conversion and 83%selectivity.The catalysts are obtained via precise depositing of CuO nanoclusters(size:~3.5 nm)at the{101}facet of the TiO2 to optimally tune exciton recombination through oxygen vacancies generation,evidenced by photoluminescence and Raman spectroscopy measurements.The turnover frequency(TOF)and the apparent quantum efficiency(AQE)of the 7%CuO/TiO2-spindle composites reach up to 23.8 molmethanol·gcat^-1·h^-1 and 55.2%at 25℃,respectively,which are substantially higher than these previously reported photocatalysts.Further,the in-situ attenuated total reflection infrared spectroscopy analysis reveals that the methanol oxidation most likely takes place through the conversion of adsorbed methoxy(CH30^*)to formaldehyde(CHO^*)intermediate,a subject of major debate for a long time.The adsorbed formaldehyde(CHO^*)thus produced reacts with another CH30^*species in its close proximity to form the final product of methyl formate.Results of this study provide insights into the reaction mechanism,and offer guidelines to systematically develop and apply photocatalysts for methanol conversion and related reactions via surface engineering.展开更多
Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electr...Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption test. The results show that the nanocomposites exhibited coral-like nanostructure, and the average crystalline size of SnO2 was 12 nm. The specific surface area of the four samples, SnO2- 0.2CuO, SnO2-0.5CuO, SnO2-1.0CuO and SnO2-2.0CuO are 72.97, 58.77, 49.72 and 54.95 m2/g, respectively. The gas sensing performance of the four samples to ethanol, formaldehyde and H2S was studied. The sensor of SnOa-0.5CuO exhibited high response to hydrogen sulfide （4173 to 10 ppm H2S, where ppm represent 10-6）, and low response to ethanol and formaldehyde. The good selectivity exhibited that the SnO2-0.5CuO nanocomposite can be a promising candidate for highly sensitive and selective gas-sensing material to H2S.展开更多
CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized b...CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized by XRD, BET specific surface area, ESEM and EDS analysis. This synthetic method provides several advantages such as simple work-up procedures, minimal amount of waste generated, short reaction time, and high yields of products.展开更多
基金support from the National Natural Science and Henan Province United Foundation of China (No. U1204601)Natural Science Foundation of Henan Province (No. 122300410298)+1 种基金Natural Science Foundation of Education Department of Henan Province (No. 13A480365)PhD Foundation of Zhengzhou University of Light Industry (No. 2010BSJJ029)
文摘In this paper, we have demonstrated a facile and low-cost synthesis of the ZnO/CuO nanocomposites by two-step hydrothermal methods. The photocatalytic properties of the as-synthesized ZnO/CuO nanocomposites have been evaluated by the photodegradation of methylene blue(MB) and methyleneorange(MO) under UV irradiation. Experimental results show that MB and MO can be degraded completely within 15 and 25 min by the ZnO/CuO nanocomposites and its photodegradation rate is 6 times faster than that of pure ZnO. This enhanced photocatalytic activity can be ascribed to the low recombination probability of photo-induced carriers due to the efficient charge transfer in the nanocomposites. The as-synthesized ZnO/CuO nanocomposite may be a promising candidate for dye photodegradation of wastewaters.
基金CSIR-09/0973(11599)/2021-EMR-I and SERB(Project no:CRG/2021/000255),Department of Science and Technology,Govt.of India。
文摘An efficient room-temperature self-powered,broadband(300 nm–1100 nm)photodetector based on a CuO–TiO_(2)/TiO_(2)/p-Si(100)heterostructure is demonstrated.The CuO–TiO_(2)nanocomposites were grown in a two-zone horizontal tube furnace on a 40 nm TiO_(2)thin film deposited on a p-type Si(100)substrate.The CuO–TiO_(2)/TiO_(2)/p-Si(100)devices exhibited excellent rectification characteristics under dark and individual photoillumination conditions.The devices showed remarkable photo-response under broadband(300–1100 nm)light illumination at zero bias voltage,indicating the achievement of highly sensitive self-powered photodetectors at visible and near-infrared light illuminations.The maximum response of the devices is observed at 300 nm for an illumination power of 10 W.The response and recovery times were calculated as 86 ms and 78 ms,respectively.Moreover,under a small bias,the devices showed a prompt binary response by altering the current from positive to negative under illumination conditions.The main reason behind this binary response is the low turn-on voltage and photovoltaic characteristics of the devices.Under illumination conditions,the generation of photocurrent is due to the separation of photogenerated electron-hole pairs within the built-in electric field at the CuO–TiO_(2)/TiO_(2)interface.These characteristics make the CuO–TiO_(2)/TiO_(2)broadband photodetectors suitable for applications that require high response speeds and self-sufficient functionality.
基金supported by Natural Science Foundation of China(81774191) Beijing Natural Science Foundation(7172031) Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th5-year Plan(CIT＆TCD201804086)
文摘OBJECTIVE Zn-doped CuO nanocomposites(nZn-CuO NPs) are novel nanoparticles synthesized by sonochemical method.This study aimed to further investigate the antitumor effects and mechanism of nZn-CuO NPs,as well as the exact mechanism of reactive oxygen species(ROS) on nZn-CuO NPs-induced death using N-acetylcysteine(NAC).METHODS The antitumor effects of nZn-CuO NPs were evaluated by MTS assay and orthotopic transplantation tumor model in nude mice.The effects of nZn-CuO NPs with or without NAC on ROS production,DNA damage,apoptosis,mitochondrial damage,autophagy,lysosome impairment,and ER and Golgi stress were determined.Also,western blot was used to detect apoptosis and autophagy related proteins,as well as NF-κB pathway related proteins.RESULTS nZn-CuO NPs significantly inhibit tumor growth both in vitro and in vivo.nZn-CuO NPs were able to cause cytotoxicity,ROS production,DAN damage mitochondrial damage,apoptosis,and autophagy,and NAC can attenuate them.Further studies showed that nZn-CuO NPs induced changes of apoptosis,autophagy and NF-κB pathway related proteins,and NAC can restore them.CONCLUSION Overall,our data demonstrated that nZn-CuO NPs could inhibit tumor growth both in vitro and in vivo by ROS-dependent regulation of apoptosis and autophagy,which might be cross-linked by NF-κB pathways.
文摘CuO·SnO2 Nanocomposite powders were prepared by solid state reaction from Cu(NO3)2·3H2O, SnCl4·5H2O with NaOH at low temperature. The crystal form, particle size and morphology of the material were characterized by XRD, TEM, FTIR, SEM-EDS and XPS. The results showed that CuO·SnO2 nanocomposite was composed of CuO with monoclinic crystalline structure and SnO2 with tetragonal crystalline structure. The average particle size of the CuO·SnO2 nanocomposite was about 10 nm.
基金supported by the University of Isfahan and a little part of financial expenses by Research Institute of Shakhes Pajouhthe cooperation of central laboratory of Water and Sewage Company of Isfahan province (ABFA)
文摘The main purpose of this work was the modification of NaX nanozeolite using copper oxide nanoparticles and various monovalent cations such as K^+, Cs^+, and Ag^+in order to make the negatively charged zeolite surface accessible for anionic forms of uranium which are the most dominant species of uranium in the contaminated radioactive waters at natural p H. Various methods such as the X-ray fluorescence(XRF), X-ray powder diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FT-IR), and atomic absorption spectroscopy(AAS) were used to characterize the final synthesized absorbents. Batch technique was used to study the adsorption behavior of uranium ions from polluted drinking water by Na X nanozeolite and its modified forms. In order to better understand the performance of them, the results were compared with those that were obtained for synthesizing bulk NaX zeolite and Na-form of clinoptilolite natural zeolite. Preliminary results indicated that uranium sorption increased as the loading level of CuO nanoparticles on NaX nanozeolite increased from 2.1 wt% to 11.2 wt%. In addition,from the obtained data, an increase in uranium removal efficiency resulted as charge/ionic radius ratio of exchanged cation decreased. Also, the effect of contact time, solid–liquid ratio, initial concentration and temperature on the adsorption process was studied. It is worth mentioning that, in this study, the sorption of uranium was performed under natural conditions of pH and the presence of competing cations and anions which are available in drinking waters.
基金Q.Q.S.thanks the Postdoctoral Science Foundation of China(No.223232),the Natural Science Foundation of Inner Mongolia Autonomous Region(No.2018BS02004)the major special topics of Inner Mongolia science and technology department(No.20181351)+3 种基金Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(No.NJYT-20-B20)the Program of Higher-level Talents of Inner Mongolia Agricultural University(No.NDYB2016-03)LiaoNing Revitalization Talents Program(No.XLYC1807121)Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme(2019)for financial support.
文摘We report experimental and mechanistic understanding of methanol oxidation to produce methyl formate using CuO/Ti02-spindle composite as a promising photocatalyst under mild conditions with over 97%conversion and 83%selectivity.The catalysts are obtained via precise depositing of CuO nanoclusters(size:~3.5 nm)at the{101}facet of the TiO2 to optimally tune exciton recombination through oxygen vacancies generation,evidenced by photoluminescence and Raman spectroscopy measurements.The turnover frequency(TOF)and the apparent quantum efficiency(AQE)of the 7%CuO/TiO2-spindle composites reach up to 23.8 molmethanol·gcat^-1·h^-1 and 55.2%at 25℃,respectively,which are substantially higher than these previously reported photocatalysts.Further,the in-situ attenuated total reflection infrared spectroscopy analysis reveals that the methanol oxidation most likely takes place through the conversion of adsorbed methoxy(CH30^*)to formaldehyde(CHO^*)intermediate,a subject of major debate for a long time.The adsorbed formaldehyde(CHO^*)thus produced reacts with another CH30^*species in its close proximity to form the final product of methyl formate.Results of this study provide insights into the reaction mechanism,and offer guidelines to systematically develop and apply photocatalysts for methanol conversion and related reactions via surface engineering.
基金financially supported by the National Natural Science Foundation of China (No. 51072141)the scientific research projects of Education Department of Hubei province (D20141503)the President Foundation of Wuhan Institute of Technology (No. 2014029)
文摘Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption test. The results show that the nanocomposites exhibited coral-like nanostructure, and the average crystalline size of SnO2 was 12 nm. The specific surface area of the four samples, SnO2- 0.2CuO, SnO2-0.5CuO, SnO2-1.0CuO and SnO2-2.0CuO are 72.97, 58.77, 49.72 and 54.95 m2/g, respectively. The gas sensing performance of the four samples to ethanol, formaldehyde and H2S was studied. The sensor of SnOa-0.5CuO exhibited high response to hydrogen sulfide （4173 to 10 ppm H2S, where ppm represent 10-6）, and low response to ethanol and formaldehyde. The good selectivity exhibited that the SnO2-0.5CuO nanocomposite can be a promising candidate for highly sensitive and selective gas-sensing material to H2S.
基金the Behbahan Khatam Alanbia University of Technology for the partial support of this work
文摘CoO-CeO2 is reported as a highly efficient and green recyclable catalyst, for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. The catalyst was synthesized by a co-precipitation method and characterized by XRD, BET specific surface area, ESEM and EDS analysis. This synthetic method provides several advantages such as simple work-up procedures, minimal amount of waste generated, short reaction time, and high yields of products.
