Seminar on the topic: Chemistry and applications

At 9:00 a.m. on July 4, 2025, IAST organized an academic exchange session at Meeting Room B with the following detailed content:

1/ Assoc. Prof. Dr. Nguyen Anh Tien presented on "Synthesis, study of structure, optical, magnetic and electrical properties of perovskite nanomaterials based on HoFeO3"

Abstract:

In this study, HoFeO3 perovskite nanomaterials doped with cobalt and manganes were successfully synthesized by a simple co-precipitation method. The concentration of cobalt and manganes doping significantly affects the structural properties and physicochemical properties of HoFeO3 substrate materials. The average crystal size and lattice volume increase with the content of doping elements. Thermogravimetric analysis (TGA) shows that the hydroxide precipitates decompose completely at about 850 °C. Transmission electron microscopy (TEM) images showed that the synthesized perovskite-based HoFeO3 nanoparticles were spherical aggregates with sizes ranging from 20–50 nm. The composition and elemental distribution maps of the synthesized samples were determined by energy dispersive X-ray diffraction (EDX-mapping). The band gap energy decreased, while the magnetization tended to increase with increasing dopant content. At a current density of 0.1 A·g–1, the specific capacity of the HoFeO3-based anode electrodes for Li-ion batteries increased gradually over the first 50–120 cycles and reached a maximum of 503 mAh.g–1. The HoFeO3-based anode electrodes also demonstrated good reversibility with asymptotic charging efficiency approaching 100 % after the first cycle. These results demonstrate the potential applications of HoFeO3-based nanomaterials in the fields of optics, magnetism and electronics.

2/ Dr. Pham Thi Thu Thao presented on "Study on the ability to trap free radicals of N-H, O-H in aromatic compounds containing Nitrogen"

Abstract:

Hydroxylamine, diphenylamine have been identified as promising antioxidants that can effectively eliminate free radicals, through the main mechanism: hydrogen transfer. Specifically, for N-phenylhydroxylamines, it is believed that both the N–H and O–H bonds act as two hydrogen-donating centers responsible for this task. The same is true for the N-H bond in diphenylamine. We used the M06-2X/6-311++G(d,p) and CBS-QB3 methods to evaluate the N–H and O–H bond dissociation enthalpies and the results were found to be in good agreement. The BDE(N–H), IE(N-H) parameters were determined and re-examined in gas phase, DMSO and water for comparison. In addition, the effects of halogen, electron-donating and electron-withdrawing substitutions at the para positions of the aromatic rings ArNHOH and Ar2NH on the BDE of both N–H and O–H bonds were also evaluated. In addition to examining the role of O–H and N–H bonds in trapping free radicals, the present study incorporated a kinetic aspect to better understand the mechanisms involved.

3/ Dr. Cao Nhat Linh presented on "Recent advances in sensor-based corrosion monitoring for reinforced concrete structures."

Abstract:

The corrosion of reinforcement in concrete is a primary cause of structural degradation, necessitating effective monitoring methods to ensure durability and safety. This work summarizes advancements in non-destructive sensor technologies for corrosion monitoring in reinforced concrete structures over the past two decades. Emphasis is placed on electrochemical techniques, including half-cell potential (HCP), concrete resistivity (CR), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and galvanostatic pulse techniques (GPT). Additionally, the review explores physical sensing methods such as fiber-optic sensors, elastic wave sensors, piezoelectric transducers, and Hall effect sensors, highlighting their applicability in real-time structural health monitoring. The discussion extends to integrated sensor systems that combine multiple measurement techniques to enhance detection accuracy and provide comprehensive corrosion assessments. Commercially available sensors and emerging technologies currently in development are critically analyzed, addressing their advantages, limitations, and field applicability. This study highlights the necessity of integrating electrochemical and physical sensors to improve monitoring accuracy and enable predictive maintenance strategies. While significant progress has been made in sensor-based corrosion monitoring, further research is required to refine existing technologies, standardized testing protocols, and enhance sensor durability under field conditions.