- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Designed synthesis of microstructure and defect-controlled Cu-doped ZnO-Ag nanoparticles: exploring high-efficiency sunlight-driven photocatalysts
摘要： Cu-doped ZnO nanoparticles composited with Ag were synthesized by one-step sol-gel method in this work, aiming at highly photocatalytic activity and possible application under sunlight (especially near ultraviolet and visible light regions, 300-760 nm) irradiation. Scanning electron microscopy (SEM) shows that the introduction of Cu inhibits particle aggregation. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that Zn(Cu)O-Ag nanoparticles (CZA NPs) are composed of metallic Ag (Ag0) and Zn(Cu)O nanocrystals; while at the Cu concentration of higher than 2%, a little CuO nanocrystals appear. Transmission electron microscopy (TEM) results evidenced the well-defined formation of Zn(Cu)O-Ag and/or CuO-ZnO-Ag heterojunctions. UV–vis spectra display that the visible absorption of the samples is obviously enhanced after the Cu introduction. At a low Cu doping level (0.2%) and moderate Cu concentration (3~5%), the blue and green photoluminescence (PL) emission strength of the samples become very weak in comparison to other samples, indicative of the high separation of photogenerated electron-hole pairs. Reasonably, the higher photocatalytic degradation (complete degradation of methylene blue (MB) and methyl orange (MO) within 40 minutes under the simulated sunlight irradiation) are achieved in these cases: low Cu doping level (0.2%) and moderate Cu concentration (3~5%) in CZA NPs. Further, we checked the effects of other factors on the photocatalytic degradation for possible application. Our results suggest that one well-designed composite type such as element-doped Zn(M)O-Ag nano-heterojunction or complicated metal oxide-ZnO-Ag nanocomposites possessing suitable band structures for the separation and utilization of photo-generated carriers, will remarkably improve the photocatalytic performance of nano-ZnO under sunlight irradiation.
关键词： ZnO-Ag nanocomposites,heterojunction,sunlight irradiation,Cu-doped ZnO,photocatalytic degradation
更新于2025-09-23 15:19:57
-
ZIF-8 derived ZnO/Zn6Al2O9/Al2O3 nanocomposite with excellent photocatalytic performance under simulated sunlight irradiation
摘要： In this contribution, ternary ZnO/Zn6Al2O9/Al2O3 nanocomposite was obtained by in situ incorporation of Al3+ during the synthesis of ZIF-8, aiming to improve the adsorption and photocatalytic performance of ZIF-8-derived ZnO under simulated sunlight irradiation. XRD, SEM, TEM, HRTEM, XPS, UV-Vis DRS, BET and PL techniques were employed for the analysis of the crystalline structure, composition, morphology, light absorption and charge separation of the samples. The photocatalytic activity of the samples was evaluated by the degradation of Methyl orange (MO) under simulated sunlight irradiation. Compared to ZIF-8-derived ZnO, the formation of ZnO/Zn6Al2O9/Al2O3 nanocomposite can provide with high BET specific surface area, reduce the band gap, inhibit the recombination of the electron-hole pairs, and hence greatly improve the photocatalytic activity. The maximum photocatalytic degradation rate of 97.5% for a high initial MO concentration of 150 mg/L-1 was obtained over ZnO/Zn6Al2O9/Al2O3 nanocomposite with molar ratio of Al/Zn as 1:1 under simulated sunlight irradiation for 60 min, which is 3.18 times higher than that of ZIF-8-derived ZnO.
关键词： Zn6Al2O9,Simulated sunlight irradiation,Al2O3,ZIF-8,ZnO,Photocatalytic degradation
更新于2025-09-19 17:15:36
-
Preparation and characterization of bismuth oxychloride/reduced graphene oxide for photocatalytic degradation of rhodamine B under white-light light-emitting-diode and sunlight irradiation
摘要： Facile and template-free two-step synthesis of bismuth oxychloride/graphene oxide (BiOCl/GO) and bismuth oxychloride/reduced graphene oxide (BiOCl/rGO) photocatalysts for degradation of rhodamine B (RhB) under low-power white light–emitting diode (wLED) irradiation (1.6 W/cm2) and sunlight is demonstrated. These photocatalysts were characterized by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray di?raction, and micro-Raman, Fourier-transform infrared, X-ray photoelectron, and UV–Vis di?use re?ectance spectroscopy. Under wLED irradiation, the prepared BiOCl/rGO photocatalysts exhibited excellent photodegradation activity toward RhB through chromophore cleavage mechanism and toward phenol in the presence of RhB with notable dye-sensitized e?ect. Through scavenging experiments, superoxide radicals were notably involved in RhB degradation. With the highest charge separation e?ciency and lowest recombination rate, the photocatalytic activity of BiOCl/rGO reached a maximum rate constant of 0.1899 min?1, 2.0 and 3.0 times higher than those of BiOCl/GO and BiOCl, respectively. In the stability study, only a slight loss (4.5%) in photodegradation was observed after BiOCl/rGO was used in ?ve cycles of photodegradation runs. Compared with commonly used photocatalyst such as TiO2 (P25), BiOCl/rGO demonstrated superior photocatalytic activity and stability under wLED irradiation for various dyestu?s (rhodamine 6 G, methylene blue, and fast green FCF) in di?erent environmental water samples (lake, pond, and sea water).
关键词： wLED-induced photodegradation,Rhodamine B,Reduced graphene oxide,Phenol,Sunlight irradiation,Bismuth oxychloride
更新于2025-09-19 17:15:36
-
Enhanced photocatalytic degradation of antibiotics in water over functionalized N,S-doped carbon quantum dots embedded ZnO nanoflowers under sunlight irradiation
摘要： ZnO is widely used as a photocatalyst in industry, however, it is still a challenge to degrade refractory antibiotics in water. In this study, a novel surface-functionalized N,S-doped carbon quantum dot (N,S-CQD) was synthesized and embedded into ZnO for the formation of a new ZnO/N,S-CQDs hybrid nanoflower via one-pot hydrothermal process. The as-prepared ZnO/N,S-CQDs showed significantly enhanced photocatalytic activity under visible and near-infrared (NIR) light irradiation, in which 72.8% of MG was decomposed after 180 min under NIR light. In addition, approximately 92.9% and 85.8% of ciprofloxacin (CIP) were degraded by ZnO/N,S-CQDs under simulated sunlight for 20 min and natural sunlight for 50 min, respectively. Furthermore, the mechanism was investigated and the results show that the surface functionalization, electron transfer, up-converted luminescence properties of N,S-CQDs, together with the highly reactive facets of ZnO nanoflowers, made great contributions to the enhanced photocatalytic activity of ZnO/N,S-CQDs. Additionally, the results of active species trapping experiments indicated that the hydroxide free radicals, holes and superoxide radical anions all played certain roles in the photocatalytic reaction. Finally, ZnO/N,S-CQDs was employed for photodegradation of antibiotics in actual water, the degradation efficiency of antibiotics still remained above 60% after 120 min. We believe that the ZnO/N,S-CQDs nanoflower is a promising photocatalyst for the degradation of refractory antibiotics under sunlight irradiation. The relatively low cost and excellent photocatalytic performance of ZnO/N,S-CQDs is beneficial for industrial applications.
关键词： antibiotics,carbon quantum dots,ZnO nanoflowers,photocatalysis,sunlight irradiation
更新于2025-09-16 10:30:52
-
Enhanced photocatalytic performance of sphere-like AgCl/ rGO catalysts under simulated and natural sunlight irradiation
摘要： Here we prepared sphere-like AgCl by stirring in the presence of sodium oleate, and loaded it on the surface of reduced graphene oxide (rGO) to form sphere-like AgCl/ rGO composite. Sphere-like AgCl exhibited enhanced degradation e?ciency after the inserting of rGO with degrading 80.6% of tetracycline (TC) within 90 min, which was about 15.4% higher than pristine spherical AgCl (65.2%) under simulated sunlight irradiation. Moreover, ?ve times cycling test of the obtained samples had revealed the improved stability of AgCl/ rGO. The remarkable photocatalytic activity was mainly due to the better interaction between AgCl and rGO, where charge separation and transfer as well as the utilization of sunlight were boosted. Improved photocatalytic stability was majorly ascribed to the fast electrons transfer from AgCl to rGO before the reduction of Ag+ to Ag. Besides, a possible photocatalytic reaction mechanism under simulated sunlight was proposed. Meanwhile, AgCl/ rGO also exhibited better photocatalytic e?ciency for the degradation of TC under natural sunlight irradiation (73.2%), which is hopeful for practical application of photocatalysts.
关键词： Natural sunlight irradiation,Sphere-like AgCl/ rGO,Tetracycline,Photocatalyst
更新于2025-09-09 09:28:46
-
Effect of temperature on structural and optical properties of solvothermal assisted CdS nanowires with enhanced photocatalytic degradation under natural sunlight irradiation
摘要： Photocatalytic degradation of toxic dyes is an important topic across the globe. This paper reports the photocatalytic degradation of methylene blue (MB) dye using cadmium sulfide (CdS) nanowires as a photocatalyst under natural sunlight irradiation. The CdS nanowires were successfully synthesized by a solvothermal route using ethylenediamine as a solvent with a series of different reaction temperature from 160 to 200 °C for a fixed time of 24 h. Multiple characterization techniques were used to investigate the structural, morphology, optical and photocatalytic study of as-synthesized CdS samples. The XRD patterns reveal highly crystalline CdS nanomaterials with a hexagonal crystal structure. The FESEM and HRTEM observations clearly confirmed a large number of uniform nanowires grown in different directions and interconnected with each other. The stoichiometric ratio of Cd:S is almost 1:1, confirmed by EDS analysis. Room temperature PL spectra of CdS nanowires exhibit a narrow emission at a wavelength of 512 nm. The CdS nanowires synthesized at 200 °C shows the excellent photocatalytic performance with highest photodegradation efficiency has reached up to 98.75% within 20 min, under sunlight irradiation. The 93.06% and 89.10% photodegradation efficiency were observed in CdS nanowires synthesized at 180 °C and 160 °C, respectively. From these result, it is observed that the crystallite size and morphology of CdS nanowires are the influence factors for the photodegradation efficiency of MB dye. Furthermore, the mechanism of MB dye photodegradation using CdS nanowires was discussed. These CdS nanowires with high photocatalytic activity can be used for future in water pollutant degradation.
关键词： Hexagonal CdS,Solvothermal synthesis,MB dye degradation,Reaction temperature,Sunlight irradiation
更新于2025-09-04 15:30:14