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Grafting of CdTe quantum dots on thiol functionalized MCM-41 mesoporous silica for 68Ga radiolabeling: introducing a novel PET agent
摘要： Radiolabeled fluorescent nanocomposite, 68Ga@CdTeQDs@SH-Propyl@MCM-41, was prepared. The prepared material was characterized using X-ray diffraction, thermal analysis, radio-thin layer chromatography, field Emission scanning electron microscopy, transmission electron microscopy and N2 adsorption and desorption measurements. In vivo biodistribution and tumor avidity of the nanoconposite was investigated among the organs of rats bearing fibro sarcoma tumor. The results showed that the mesoporous structure of MCM-41 after functionalization and grafting of quantum dots remains intact and the nanosilica can be labeled with 68Ga radionuclide very fast. The results showed a rapid and high tumor uptake for 68Ga@CdTeQDs@SH-Propyl@MCM-41 which revealed that the tumor uptake is modulated by size and character of the host.
关键词： CdTe Quantum Dots,68Ga-Radiolabeled fluorescent nanocomposite,MCM-41
更新于2025-09-23 15:21:01
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Highly efficient photocatalytic reduction of CO2 on surface-modified Ti-MCM-41 zeolite
摘要： Three dimensional microporous zeolites have attracted much attention in catalysis because of their large BET surface area and abundant pores. Herein, Ti-MCM-41 zeolites with different molar ratio of Si/Ti were synthesized, and the surface acidity and active sites were adjusted by the modification of basic-earth metal oxides, and noble metal nanoparticles. The photocatalytic activity and selectivity were evaluated by the reduction of CO2 to CH4 and CO. The results indicated that the efficiency and selectivity of CO2 photoreduction to CH4 of Ti-MCM-41 zeolites were 93 ppm·g-1·h-1 and 29% in the ratio Si/Ti=10 under keeping the zeolite structure, and which is much higher than that of P25 with the value of 24 ppm·g-1·h-1 and 23%. When the surface of Ti-MCM-41 zeolites was modified by different basic-earth metal oxides, the photo-reduction activity of CO2 to CH4 increased about 1.5 times with MgO modification, and the selectivity of CO2 to CH4 improved to 42%. Moreover, the photoactivity and selectivity enhanced to 8835 ppm·g-1·h-1 and 93% when the surface was further decorated by Pt nanoparticles, while the selectivity of CO2 to CO reached 94% when Pd was loaded. Our work reveal reasonably that adjusting the acidity and active site of the microporous zeolites is a highly efficient way to improve the photocatalytic efficiency of CO2 reduction.
关键词： Ti-MCM-41 zeolite,active sites,surface acidity,CO2 photoreduction
更新于2025-09-09 09:28:46
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Synthesis of Al-MCM-41@Ag/TiO <sub/>2</sub> Nanocomposite and Its Photocatalytic Activity for Degradation of Dibenzothiophene
摘要： Mesoporous Al-MCM-41@Ag/TiO2 nanocomposites were synthesized successfully by combining the sol-gel method and hydrothermal treatment, using titanium isopropoxide (TTIP), AgNO3, and Vietnamese bentonite as precursors of Ti, Ag, and Si, respectively. The synthesized materials were well characterized by X-ray powder di?raction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption isotherm measurements, energy dispersive X-ray spectroscopy (EDX), UV-visible di?use re?ectance spectroscopy (UV-Vis/DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated by the photodegradation of dibenzothiophene (DBT) under both UV and visible light irradiation. MCM-41@Ag/TiO2 catalyst exhibited high catalytic activity for the oxidative desulfurization (ODS) of DBT reaching almost 100% conversions at 50°C after 2 h under UV and visible light irradiations. The signi?cant enhanced degradation of DBT over Al-MCM-41@Ag/TiO2 might be due to the synergy e?ects of high surface area of MCM-41, well-distributed TiO2 anatase, and reduced electron-hole recombination rates due to the dispersion of Ag nanoparticles.
关键词： photocatalytic activity,Al-MCM-41@Ag/TiO2,dibenzothiophene,visible light irradiation,oxidative desulfurization
更新于2025-09-04 15:30:14
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Synthesis of Cu-Doped Ti-Containing MCM-41 and its Photocatalytic Performance for Indoor Air Purification
摘要： The prepared catalysts were synthesized in a mild way and characterized by various analytical instruments including X-ray diffraction, nitrogen physisorption, UV-visible spectroscopy, high resolution-transmission electron microscopy and X-ray photoelectron spectroscopy. All samples exhibited the typical mesoporous structure and spherical structure. Copper and titanium species in the MCM-41 support were well anchored on the mesoporous framework in the form of metal oxides. The adsorption tests for formaldehyde examined the positive effect of metal incorporation. In the static state test, MCM-41 adsorbed 31 % of formaldehyde and Ti/Cu-MCM-41 elevated this value to 41 %. Moreover, Ti/Cu-MCM-41 demonstrated the superior photocatalytic performance under both UV- and visible-light irradiation, achiveing 57 % and 18 % of formaldehyde degradation at the end of reaction, respectively. With the X-ray photoelectron spectroscopy and UV-Visible results, an intense interaction between Ti and Cu was observed and the synergy effect mechanism in the bimetallic catalyst was proposed.
关键词： MCM-41,Cu-Doped Ti,Air purification,Photocatalyst
更新于2025-09-04 15:30:14