Laboratory Of Plasma Technology

FUNCTIONS / MISSIONS:

Study the physical and physico-chemical processes that occur when plasma interacts with materials.

Develop plasma technology oriented toward applications in material fabrication and processing, agriculture, medicine and healthcare, and environmental protection.

MAIN RESEARCH DIRECTIONS:

Field 1: Study the fabrication processes of metallic nanomaterials, metal oxide nanomaterials, and carbon nanomaterials using thermal plasma methods.

Field 2: Study the synthesis processes of various nanomaterials using cold plasma methods.

Field 3: Develop cold plasma devices to serve basic research and practical applications (in agriculture, biomedicine, and materials).

Field 4: Investigate the electronic structures of atomic clusters (nanoclusters) and design superatoms.

Field 5: Conduct materials informatics research applied to the prediction of material properties.

Field 6: Research and develop automated laboratories for the synthesis of nanomaterials.

CONTACT INFORMATION OF THE HEAD OF LABORATORY:

• Academic title, full name: Prof. Dr. Nguyễn Thanh Tùng
• Office address: Room 321, A2 Building
• Mobile phone: +84 912 994 444
• Email: tungnt@ims.(*) - replace (*) = vast.ac.vn

KEY ACHIEVEMENTS

Cold Plasma Method for Nanomaterial Synthesis (AuNPs)

The synthesis of metallic nanoparticles (Au, Ag) has been extensively studied using various chemical and physical methods, each with its own advantages and limitations. The synthesis of nanostructured materials using cold plasma technology represents a hybrid approach between chemical and physical synthesis, enabling the fabrication of diverse nanomaterials.

We successfully synthesized gold nanoparticles functionalized with polydopamine (Au@PDA NPs) using the cold plasma method. Free electrons and reactive oxygen species generated from plasma simultaneously reduced Au³⁺ ions and oxidized dopamine (DA) monomers to form Au@PDA NPs. Key parameters such as chloroauric acid concentration, dopamine concentration, and reaction time were systematically investigated to determine optimal reaction conditions.

Characterization techniques including TEM, SEM, UV-Vis, XPS, and DLS were employed to analyze the physicochemical properties of Au@PDA NPs. Specifically, for a solution of 0.2 mM HAuCl₄, the optimal dopamine concentration and reaction time were determined as 0.05 mM and 5 minutes, respectively. The average diameter of the optimized Au@PDA NPs was 44.4 ± 4.8 nm. Moreover, the nanoparticles remained stable for at least two months post-synthesis.

Additional studies on nanomaterial synthesis via cold plasma have also been conducted at the Plasma Technology Laboratory. Results have been published in Green Chemistry (2020), Journal of Industrial and Engineering Chemistry (2021), and Nanotechnology (2021).

Synthesis of Oxygen-Deficient Tungsten Oxide Nanomaterials Using Thermal Plasma Technology

Oxygen-deficient tungsten oxide, denoted WO₃₋ₓ, represents a structurally distinct form of WO₃, exhibiting superior properties for various applications. Although numerous synthesis methods have been reported, achieving environmentally friendly, kilogram-scale production of WO₃₋ₓ nanoparticles remains highly challenging.

In this study, a DC thermal plasma method employing three plasma torches simultaneously generated a high-temperature zone (6000–10000 K), instantly vaporizing the precursor material upon contact, followed by condensation leading to nanoparticle formation. Using large-particle WO₃ powder (~50 μm, yellow) as the precursor, we successfully fabricated oxygen-deficient WO₃₋ₓ nanoparticles (deep blue) with nanometer-scale sizes.

This direct and rapid approach avoids harmful chemical agents, making it highly suitable for large-scale production of various nanomaterials. The thermal plasma technology enables high-yield production (1–2 kg/h) of high-purity, high-quality WO₃₋ₓ nanoparticles. This achievement has been registered for intellectual property protection.

Synthesis of Porphyrin@g-C₃N₄/Ag Nanocomposites for Enhanced Photocatalytic Degradation of Organic Dyes in Water

Photocatalysis activated by sunlight offers an efficient and environmentally friendly method for wastewater treatment and pollutant removal. Inspired by the light-harvesting properties of chlorophyll from porphyrins, we synthesized porphyrin@g-C₃N₄/Ag nanocomposites through self-assembly, using Cleistocalyx operculatus leaf extract as a “green” reducing agent in the synthesis of g-C₃N₄/Ag.

The resulting nanocomposite exhibited excellent photocatalytic efficiency in degrading Rhodamine B (RhB), achieving a removal rate of up to 97% after 90 minutes of irradiation. Reusability tests confirmed the high stability of porphyrin@g-C₃N₄/Ag, demonstrating its potential as a robust photocatalyst for practical dye wastewater treatment.

Figure 1. Proposed degradation mechanism of RhB dye using the porphyrin@g-C₃N₄/Ag photocatalyst.

 

Study on the Mechanism and Kinetics of Hydrogen Adsorption/Absorption on AgₙCr Nanomaterials (n = 1–12)

The hydrogen adsorption/absorption capability of nanoalloy systems has attracted significant attention due to their potential applications in catalysis and energy storage. The research group led by Prof. Dr. Nguyễn Thanh Tùng investigated the mechanism and kinetics of hydrogen adsorption/absorption on AgₙCr nanoclusters of varying sizes (n = 1–12) using quantum chemical calculations.

The results revealed that hydrogen initially adsorbs on the AgₙCr surface in a molecular form, which subsequently dissociates into atomic hydrogen on the material surface. The preferred adsorption sites for hydrogen can be either Cr or Ag, depending on the coordination number, electronegativity of the atoms, and the geometric structure of the nanocluster.

Calculated binding energies and second-order energy differences for the Ag₃Cr–H₂, Ag₆Cr–H₂, and Ag₉Cr–H₂ systems indicate that these configurations are energetically more stable than atomic adsorption states. Kinetic analyses showed that the dissociation of H₂ adsorbed on Ag₂Cr, Ag₃Cr, Ag₆Cr, and Ag₇Cr surfaces is both thermodynamically and kinetically favorable. In contrast, for Ag₄Cr or clusters with n = 1, 5, and 8–12, atomic hydrogen adsorption is unlikely due to significant energy barriers or energetically preferred alternative states.

Notably, the Ag₃Cr–H₂ system was found to be highly stable with negligible reaction barriers, suggesting its potential as an efficient surface adsorbent for catalytic and hydrogen storage applications. These results were published in the article “A DFT study of hydrogen adsorption on small AgₙCr clusters (n = 1–12)”, Ngo Thi Lan et al., ACS Omega 7, 37379 (2022), and were selected by the Editorial Board for the journal cover in October 2022.

Figure 2. Cover page of ACS Omega highlighting the article “A DFT study of hydrogen adsorption on small AgₙCr clusters (n = 1–12).”

Research Plan 2026–2030

Figure 3. Schematic of an autonomous laboratory for nanomaterial synthesis using plasma technology.

 

Between 2026 and 2030, the Plasma Technology Laboratory will focus on the project “Research, Development, and Application of an Autonomous Laboratory Model for Advanced Material Synthesis and Data Production”. The aim is to establish a modern, highly integrated experimental system that combines cold plasma techniques, automation, and artificial intelligence (AI) to support advanced materials research.

The project’s primary objective is to design and construct an autonomous laboratory capable of synthesizing metallic nanomaterials using cold plasma, while simultaneously collecting, processing, and managing data in accordance with the FAIR principles (Findable – Accessible – Interoperable – Reusable). This system will enable experimental process optimization, minimize manual intervention, and enhance the efficiency of material discovery.

In addition, the project seeks to synthesize selected advanced nanomaterials using the autonomous laboratory and to leverage the resulting datasets for AI-driven predictions of new materials or novel properties. By doing so, the project not only contributes to the digitalization and automation of materials research and development but also opens new opportunities for applying AI in materials science in Vietnam.

 

SELECTED PUBLICATIONS

1. Mai NT, , Tung NT et al. “Systematic Investigation of the Structure, Stability, and Spin Magnetic Moment of CrMn Clusters (M = Cu, Ag, Au, and n = 2–20) by DFT Calculations” ACS Omega (2021), 6, 31, 20341-20350. Front cover: https://pubs.acs.org/toc/acsodf/6/31

2. Mai NT, Tung NT et al. “Photofragmentation Patterns of Cobalt Oxide Cations ConOm+ (n = 5–9, m = 4–13): From Oxygen-Deficient to Oxygen-Rich Species” The Journal of Physical Chemistry A (2020) 124 (37), 7333-7339. Front cover: https://pubs.acs.org/toc/jpcafh/124/37

3. Lan NT, Tung NT et al. “Exploring hydrogen adsorption on nanocluster systems: Insights from DFT calculations of Au9M2+ (M= Sc-Ni)” Chemical Physics Letters (2023), 831, 140838. Front cover: https://www.sciencedirect.com/journal/chemical-physics-letters/vol/831/suppl/C.

4. Linh NN, Liem NQ et al. “In situ plasma-assisted synthesis of polydopamine-functionalized gold nanoparticles for biomedical applications” Green Chemistry (2020), 22, 19, 6588-6599.

5. Xuan LTQ, Linh NN, Thuan DN “Synthesis of stabilizer-free, homogeneous gold nanoparticles by cold atmospheric-pressure plasma jet and their optical sensing property” Nanotechnology (2021), 33, 10, 105603.

6. Thu MN, Tung NT, Linh NN “The Outlook of Flexible DBD-Plasma Devices: Applications in Food Science and Wound Care Solutions” Materials Today Electronics (2024), 7, 100087.

7. Tung NT, Giang NT, Tung NH et al. “Facile preparation of porphyrin@ g-C3N4/Ag nanocomposite for improved photocatalytic degradation of organic dyes in aqueous solution” Environmental Research (2023), 231, 115984

8. Lan NT, Tung NT et al. “Density Functional Study of Size-Dependent Hydrogen Adsorption on AgnCr (n = 1–12) Clusters” ACS Omega (2022), 7, 42, 37379-37387. Front cover: https://pubs.acs.org/toc/acsodf/7/42

9. Tung NH et al. “Temperature Dependence of Optical Properties of MoS2 and WS2 Heterostructures Assessed by Spectroscopic Ellipsometry” Nanomaterials (2025), 15, 76.

EQUIPMENTS

No.	Equipment Name	Features	Installation Location	Operators
1	Thermal Plasma Nanomaterial Synthesis System (Origin: Korea)	A modern system enabling nanomaterial synthesis using three DC thermal plasma torches with a total power >100 kW, operating on 380 VAC. Equipped with a plasma sintering reaction chamber at 3000–6000 °C, allowing fabrication of various nanomaterials (10–100 nm) at pilot scale (~250 g/hour).	Room P123, A2	Dr. Nguyễn Hoàng Tùng
2	Plasma Jet System (Origin: China)	Utilizes a high-voltage power supply combined with plasma jet heads, operating with Ar gas or Ar mixed with O₂/N₂ to generate plasma jets.	Room P125, A2	Dr. Nguyễn Nhật Linh
3	Microwave Plasma System (Origin: France)	Operates with 220 V – 50 Hz input, maximum power up to 4 kW. Designed for large-scale material surface treatment applications.	Room P124, A2	Dr. Nguyễn Nhật Linh
4	Real-time UV-Vis-NIR Spectrophotometer (Origin: China)	Enables spectroscopic measurements (emission, absorption) of materials and plasma in real time.	Room P124, A2	Dr. Nguyễn Nhật Linh
5	Microwave Synthesis System (Origin: Austria)	Enables sequential small-scale microwave synthesis, providing full operational parameters with temperatures up to 300 °C and pressures up to 30 bar.	Room P124, A2	Dr. Nguyễn Nhật Linh
6	Infrared Spectroscopy System for Microscale Samples	1. FTIR Spectrometer (Manufacturer: Lumex, Origin: Canada) 2. Infrared Microscope (Origin: USA) Used for FTIR analysis of liquid or gaseous samples at micrometer scale.	Room P211, A2	Dr. Nguyễn Hoàng Tùng