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Tailoring ZnO Nanostructures through Precursor Concentration and Hydrothermal Duration: A Pathway to Efficient Solar Water Splitting
(2026-11-10)
Borklom, Phanlapa
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Khemasiri, Narathon
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Jessadaluk, Sukittaya
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Rattanawarinchai, Prapakorn
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Kayunkid, Navaphun
This work investigated the formation of ZnO nanostructures on ITO substrates prepared by self-seeding hydrothermal synthesis for photoelectrochemical ( PEC) water splitting applications. The hydrothermal parameters, precursor concentration and hydrothermal time, were varied to explore their influences on ZnO crystallinity, morphology, and PEC performance. The combinations of X-ray diffraction and field emission scanning electron microscopy revealed highly oriented ZnO nanostructures with diverse morphologies, including small granules, nanorods, dense films, and hexagonal platelets. Topographic profiling of the morphological parameters revealed complex relationships between synthesis conditions and nanostructure characteristics, highlighting the importance of considering aggregation phenomena in substrate-based growth. This aggregation led to deviations from conventional crystal growth theory predictions, particularly for grain density and diameter evolution. PEC performance evaluation identified ZnO nanorods as the optimal morphology, exhibiting a photocurrent density of 0.182 mA/cm² at 0 V vs. Ag/AgCl. Further enhancement was achieved by decorating ZnO nanorods with CdS nanoparticles, resulting in a six-fold increase in photocurrent density (1.2 mA/cm²). This improvement is attributed to expanded light absorption and improved charge separation at the CdS/ ZnO interface. Our findings demonstrate the potential of rationally designed ZnO-based nanostructures in the advancement of solar-driven water splitting technologies and provide valuable insights for optimizing PEC systems through precise control of hydrothermal synthesis parameters, consideration of substrate-induced aggregation, and strategies for photoelectrochemical (PEC) water splitting applications.
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Solvent-Dependent Green Synthesis of ZnO Nanopowders Using Mitragyna speciosa Leaf Extract: Impact on Piezo-Photocatalytic and Antibacterial
(2026-07-01)
Sanyen, Thanyapa
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Songpanit, Maneerat
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Kansaard, Thanaphon
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Wirunchit, Supamas
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Chutipaijit, Sutee
ZnO nanopowders were synthesized via a solvent-mediated green route using Mitragyna speciosa Korth. leaf extract as reducing and stabilizing agents. Deionized water and methanol were employed to tailor the phytochemical composition of the extracts. The influence of extract concentration (5–20 mL) and solvent polarity on structural, morphological, and functional properties was systematically investigated. Structural analyses confirmed the formation of Zn-O bonds and a phase-pure hexagonal wurtzite ZnO without secondary phases. Surface morphology revealed solvent-dependent morphological evolution toward spherical shapes and reduced aggregation in the methanol-derived system. For antibacterial activity, green ZnO nanopowders demonstrated enhanced biocidal effects against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, comparable to that of commercial ZnO nanoparticles. Enhanced piezo-photocatalytic degradation of rhodamine B was achieved under combined light and ultrasonic irradiation, with superior performance observed for methanol-derived ZnO. This enhancement is attributed to the synergistic interplay of solvent-induced defect states, reduced particle size, and piezoelectric field-driven charge separation. Scavenger analysis confirmed that superoxide radicals ((Formula presented.)) dominate the degradation pathway by green-synthesized ZnO nanopowders prepared from different solvent extracts. Thus, a correlation between solvent-mediated phytochemical environments and piezo-photocatalytic activity provides new insights for the design of sustainable, high-performance ZnO-based catalysts.
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Influence of Dragon Fruit Peels on the Synthesis of Antibacterial Nano Zinc Oxide (Nano-ZnO) via Green Synthesis Method
(2026-05-20)
Sakulpeeb, Natchayaporn
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Koetniyom, Wantana
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Chutipaijit, Sutee
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Rahong, Sakon
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Kayunkid, Navaphun
This research focused on adding value to dragon fruit peel waste by utilizing it in the synthesis of antibacterial nano zinc oxide (Nano-ZnO) through a green synthesis process. In this study, all the dragon fruit peels were extracted using the solvent extraction technique with three different solvents (deionized water, ethanol, and methanol) for 1, 2, 3, 4, and 5 h, respectively. The amount of flavonoids from the extract was determined using UV-Vis spectrophotometer to obtain the optimum extraction time, which was 4 h for DI water as the solvent. Moreover, antibacterial Nano-ZnO was synthesized successfully by a green synthesis process using zinc nitrate Zn(NO3)2 and the extracts. The molecular vibrations as well as the crystal structure and morphology were investigated by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM), respectively. Additionally, the antibacterial efficacy of the nano-zinc oxide samples was evaluated using disc diffusion method. Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were the test agents. The research shows that the X-ray diffraction patterns of all synthesized ZnO nanoparticles (NPs) exhibited a wurtzite (hexagonal) crystal structure. FT-IR spectroscopy confirmed the presence of Zn-O stretching vibrations at approximately 500 cm⁻¹. Furthermore, the FE-SEM reveals that ZnO-yellow particles displayed spherical morphologies with an average particle size of 145 nm. At the same time, ZnO-White and ZnO-Red nanoparticles exhibited a combination of rod-like and elliptical morphologies, with average particle sizes of 168 nm and 321 nm, respectively. In addition, the antibacterial activity demonstrates effective inhibition against S. aureus and E. coli in all three ZnO nanoparticle conditions.
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Green synthesis and optimized annealing tempserature effects on zinc oxide nanoparticles using mango peel extract
(2026-01-01)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Meedech, Woradech
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Chutipaijit, Sutee
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Koetniyom, Wantana
This study presents the green synthesis of zinc oxide nanoparticles (ZnO-NPs) using mango peel extract (MgE) as a natural reducing and stabilizing agent. Phytochemical extraction was performed with deionized water, ethanol, and methanol for 1 h to 5 h, with deionized water at 4 h yielding the highest flavonoid content. Using zinc nitrate as a precursor, 25 mL of MgE successfully facilitated the synthesis of ZnO-NPs (ZnO-25MgE). It was found that annealing temperature at 400°C for 6 h produced pure ZnO. The obtained nanoparticles were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FE-SEM). XRD confirmed the crystalline structure with an average size of 6.67 nm, while FT-IR and FE-SEM analyses revealed Zn–O vibrations, residual organics, and nanoscale morphology. Thermogravimetric analysis (TGA) indicated the appropriate annealing temperature for the removal of organics. For comparison, chemically synthesized ZnO was also characterized, and its antibacterial activity was assessed via disc diffusion against Escherichia coli and Staphylococcus aureus. The results demonstrated notable inhibition, highlighting the potential of biosynthesized ZnO-NPs for antimicrobial applications.
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Flavonoid Extraction from Mango Peels for Nanoparticles by Green Synthesis Process
(2025-09-03)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Chutipaijit, Sutee
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Nukaew, Jiti
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Koetniyom, Wantana
This research study explored the extraction of flavonoids from ripe and raw mango peels using different solvents (deionized water, methyl alcohol, and ethyl alcohol) over varying durations. The extracted compounds were then employed in synthesizing titanium dioxide nanoparticles (TiO2 NPs) via a green chemical process using titanium isopropoxide. Optimal extraction, yielding the highest flavonoid content, was achieved with deionized water after 3 h for ripe peels and 4 h for raw peels. The titanium dioxide nanoparticles synthesized exhibited an anatase crystal structure, as confirmed by XRD, Raman, and FTIR techniques. SEM images showed that the nanoparticles were evenly distributed and had a smooth surface. The titanium dioxide nanoparticles demonstrated stronger antibacterial activity against Escherichia coli than Staphylococcus aureus. Furthermore, raw mangoes were found to be more effective in inhibiting bacterial growth than ripe mangoes.
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GREEN SYNTHESIS OF ZINC OXIDE NANOPARTICLES FROM LEMON PEEL EXTRACT AND THEIR ANTIBACTERIAL ACTIVITY
(2024-01-01)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Chutipaijit, Sutee
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Nukaew, Jiti
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Koetniyom, Wantana
This research project aimed to study the extraction of flavonoids from lemon peels using different solvents, namely deionized water (DI water), isopropanol, ethanol, and methanol. Among these, DI water yielded the highest amount of flavonoids. The extracted compounds were then utilized for the synthesis of zinc oxide nanoparticles (ZnO NPs) through a green chemical method. Various amounts of lemon peel extract (10, 15, 20, 25, and 30 ml) were mixed with Zn(NO3)2 during the synthesis process. The ZnO NPs were characterized using UV-VIS spectrophotometry, X-ray diffractometry (XRD), Fourier transform-infrared spectrometry (FT-IR), and Raman spectrometry. The results revealed successful synthesis of ZnO NPs, except for those produced using DI water extract, which exhibited a different structure (wurtzite). Subsequently, the antibacterial properties of the ZnO NPs were tested against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) using the disc diffusion method. The ZnO NPs synthesized from different solvent extracts demonstrated effective inhibition zones against both bacterial strains, indicating their potential as antibacterial agents.
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Influence of Antimony Species on Electrical Properties of Sb-Doped Zinc Oxide Thin Films Prepared by Pulsed Laser Deposition
(2023-06-01)
Jessadaluk, Sukittaya
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Khemasiri, Narathon
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Kayunkid, Navaphun
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Rangkasikorn, Adirek
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Wirunchit, Supamas
This study systematically investigates the influence of antimony (Sb) species on the electrical properties of Sb-doped zinc oxide (SZO) thin films prepared by pulsed laser deposition in an oxygen-rich environment. The Sb species-related defects were controlled through a qualitative change in energy per atom by increasing the Sb content in the Sb<inf>2</inf>O<inf>3</inf>:ZnO-ablating target. By increasing the content of Sb<inf>2</inf>O<inf>3</inf> (wt.%) in the target, Sb3+ became the dominant Sb ablation species in the plasma plume. Consequently, n-type conductivity was converted to p-type conductivity in the SZO thin films prepared using the ablating target containing 2 wt.% Sb<inf>2</inf>O<inf>3</inf>. The substituted Sb species in the Zn site (Sb<inf>Zn</inf>3+ and Sb<inf>Zn</inf>+) were responsible for forming n-type conductivity at low-level Sb doping. On the other hand, the Sb–Zn complex defects (Sb<inf>Zn</inf>–2V<inf>Zn</inf>) contributed to the formation of p-type conductivity at high-level doping. The increase in Sb<inf>2</inf>O<inf>3</inf> content in the ablating target, leading to a qualitative change in energy per Sb ion, offers a new pathway to achieve high-performing optoelectronics using ZnO-based p–n junctions.
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ZnO Nanoparticles Synthesis and Characterization by Hydrothermal Process for Biological Applications
(2023-05-01)
Wirunchit, Supamas
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Koetniyom, Wantana
This research is interested in the development of zinc oxide (ZnO) nanoparticle synthesis by hydrothermal precipitation solutions for biological applications. The synthesis of ZnO nanoparticles study from zinc nitrate (Zn(NO<inf>3</inf>)<inf>2</inf>) precursor under the three precipitator solutions consists of potassium hydroxide (KOH), sodium hydroxide (NaOH), and ammonium hydroxide (NH<inf>4</inf>OH), respectively. The synthesis of ZnO nanoparticles is investigated using the following techniques: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy techniques. The structure and size of the ZnO nanoparticles are analyzed by using a field emission scanning electron microscope (FE-SEM), and finally, the antibacterial efficacy of the ZnO nanoparticles is studied. The hydrothermal synthesis condition realizes that the smallest ZnO nanoparticles come from the zinc nitrate (Zn(NO<inf>3</inf>)<inf>2</inf>) precursor reacted with sodium hydroxide (NaOH) precipitator at 120 °C for 4 h.
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Multi Self-cleaning Properties of Zinc Oxide Nanoparticles/ Polydimethylsiloxane (ZnO/PDMS) Composite on Polyester Textile
(2023-03-02)
Wirunchit, Supamas
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Wonganan, Narin
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Koetniyom, Wantana
Self-cleaning textiles can be divided into three categories, which are the physical, chemical, and biological self-cleaning types. Physical self-cleaning refers to the lotus effect, which relates to the hydrophobic properties of the textile. Chemical self-cleaning is the degradation of color stains, discolored solutions and other organic species that come into contact with textiles. The last is biological self-cleaning, which is the ability to kill bacteria that become attached to the textiles. In this research, the development of all three self-cleaning properties of polyester textile coated with zinc oxide nanoparticles/ polydimethylsiloxane (ZnO/ PDMS) composite was focused. The ZnO nanoparticles were synthesized by a hydrothermal process, which involved blending PDMS with various concentrations of ZnO nanoparticles. The polyester textile was coated with ZnO/ PDMS composite solution via a dip coating technique done with various dipping times. The lotus effect, which depends on hydrophobic properties, was analyzed by water contact angle measurement. The chemical self-cleaning of the polyester textile was examined by photocatalytic methylene blue dye degradation with UV-Vis spectrometry. The inhibition zone of antibacterial activity was tested via disc diffusion technique. From these results, it was found that the polyester textile coated with ZnO/PDMS composite demonstrated all self-cleaning properties, physical, chemical and biological, in a significantly way.
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Study of the Titanium Dioxide Nanoparticles Used as UV absorber on Natural Herbal Extract Sunscreen Products
(2022-08-12)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Koetniyom, Wantana
This research focuses on the effects of UV absorber on natural herbal extracts including Wan Nga-chang (Ivory) and Wan Tan-diao containing Glycoside and Tannin with solvent prepared via the maceration method. The concentrations of UV absorber in this study, Titanium Dioxide (TiO<inf>2</inf>), were varied from 5, 10, 15 % by weight and compared to the unadded reference material. The characteristics and properties of sunscreen products were analyzed by UV-Vis spectroscopy, X-ray diffraction technique (XRD) and Fourier Transform-Infrared spectrometer (FT-IR). The results of the experiment showed that the optimal concentration of UV absorber is herbal cream and TiO<inf>2</inf>at concentrations of 10%wt. From XRD and FT-IR techniques confirmed the elements and functional group of herbal extract and TiO<inf>2</inf>, respectively.

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