Seminar khoa học của PGS.TS Lã Đức Dương, PGS.TS Nguyễn Thị Hoài Phương và TS. Trần Văn Chinh

Vào 14h00, ngày 23/8/2024 Viện IAST tổ chức buổi trao đổi học thuật tại Phòng họp Tầng 5 Thư viện với nội dung chi tiết như sau: 

PGS.TS Nguyễn Thị Hoài Phương trình bày về "Study on the ability to remove azo dyes of the metal-organic framework material MIL-101(Cr)"

Tóm tắt: 

MIL-101(Cr) is formed from 1,4- benzene dicarboxylate and chromium trimer bridges and possesses a zeotype and medium pore structure along with a large BET-specific surface area, the bases for it to be a leading material in environmental remediation applications. This study synthesized the MIL-101(Cr) metal-organic framework using the hydrothermal method. The formed materials have sharp crystalline morphology octahedral size from 100-300 nm. XRD plot showing peaks at 21.10o and 26,73o assigned to MIL-101(Cr). The surface area of this material calculated by the N2 adsorption isotherm method gives the result of ~ 2,900 m2/g. This material can remove organic dyes by the simultaneous photocatalytic adsorption mechanism. The ability to remove methyl orange at an initial concentration of 10 ppm was over 90%.

TS. Trần Văn Chinh trình bày về "New TiO2-doped Cu–Mg spinel-ferrite-based photocatalyst for degrading highly toxic rhodamine B dye in wastewater"

Tóm tắt:

The quest for finding an effective photocatalyst for environmental remediation and treatment strategies is attracting considerable attentions from scientists. In this study, a new hybrid material, Cu0.5Mg0.5Fe2O4–TiO2, was designed and fabricated using coprecipitation and sol-gel approaches for degrading organic dyes in wastewater.  The prepared hybrid materials were fully characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results revealed that the Cu0.5Mg0.5Fe2O4–TiO2 hybrid material was successfully synthesized with average particle sizes of 40.09 nm for TiO2 and 27.9 nm for Cu0.5Mg0.5Fe2O4. As the calculated bandgap energy of the hybrid material was approximately 2.86 eV, it could harvest photon energy in the visible region. Results indicate that the Cu0.5Mg0.5Fe2O4–TiO2 also had reasonable magnetic properties with a saturation magnetization value of 11.2 emu/g, which is a level of making easy separation from the solution by an external magnet. The resultant Cu0.5Mg0.5Fe2O4–TiO2 hybrid material revealed better photocatalytic performance for rhodamine B dye (consistent removal rate in the 13.96 × 10−3 min−1) compared with free-standing Cu0.5Mg0.5Fe2O4 and TiO2 materials,. The recyclability and photocatalytic mechanism of Cu0.5Mg0.5Fe2O4–TiO2 are also well discussed.

PGS.TS Lã Đức Dương trình bày về "Facile synthesis of g-C3N4@porphyrin nanofiber composite via self-assembly as photoelectrode for efficient photoelectrochemical water splitting"

Tóm tắt: 

The creation of self-assembled porphyrin nanostructures and their organized arrays has garnered significant attention, with the objective of mimicking natural light-harvesting mechanisms and energy storage, as well as pioneering novel nanostructured materials for use in photocatalytic processes. This study explored the formation of porphyrin nanofibers onto the surface of g-C3N4 via self-assembly, creating a photoelectrode with remarkable potential for efficient photoelectrochemical (PEC) water splitting. By integrating these two distinct materials, the resultant hybrid structure leverages the unique properties of both components, enhancing the overall performance of the photoelectrochemical system. The fabrication process involves acid-base neutralization-induced self-assembly, leading to the formation of a well-distributed composite. The resulting photoelectrode exhibits improved charge separation and enhanced light absorption properties. Experimental analyses, encompassing techniques such as scanning electron microscoly (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and photocurrent measurements, validate the successful integration of the hybrid material and its notable photocatalytic efficiency. The porphyrin nanofiber was evenly distributed over the surface of the generated g-C3N4@porphyrin hybrid material. The photoelectrochemical measurements showed a remarkable enhancement in the photocurrent when using g-C3N4@porphyrin photoelectrode in the light-irradiating condition compared to the dark condition. The possible PEC water-splitting mechanism by g-C3N4@porphyrin photoelectrode was also proposed and discussed. This work showcases a promising avenue for advancing the field of photoelectrochemical water splitting through innovative material design and assembly strategies.