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Author: search.filters.author.Kansaard, ThanaphonSubject: search.filters.subject.sonochemical process

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    Er-Doped BiVO4/BiFeO3 Nanocomposites Synthesized via Sonochemical Process and Their Piezo-Photocatalytic Application
    (2024-06-01)
    Kansaard, Thanaphon
    ;
    Songpanit, Maneerat
    ;
    Noonuruk, Russameeruk
    ;
    Wattanawikkam, Chakkaphan
    ;
    Mekprasart, Wanichaya
    In this work, Er-doped BiVO<inf>4</inf>/BiFeO<inf>3</inf> composites are prepared using the sonochemical process with a difference of rare earth loading compositions. The crystallinity and chemical and morphological structure of as-synthesized samples were investigated via X-ray diffraction, Raman scattering, and electron microscopy, respectively. The diffuse reflectance technique was used to extract the optical property and calculate the optical band gap of the composite sample. The piezo-photocatalytic performance was evaluated according to the decomposition of a Rhodamine B organic compound. The decomposition of the organic compound was achieved under ultrasonic bath irradiation combined with light exposure. The Er-doped BiVO<inf>4</inf>/BiFeO<inf>3</inf> composite heterojunction material exhibited significant enhancement of the piezo-photocatalytic activity under both ultrasonic and light irradiation due to the improvement in charge generation and separation. The result indicates that Er dopant strongly affects the phase transformation, change in morphology, and alternation in optical band gap of the BiVO<inf>4</inf> matrix. The incorporation of BiFeO<inf>3</inf> in the composite form with BiVO<inf>4</inf> doped with 1%Er can improve the photocatalytic performance of BiVO<inf>4</inf> via piezo-induced charge separation and charge recombination retardment.
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    Structural and Optical Properties of Mn-Incorporated BiVO4 Nanoparticles Synthesized by Sonochemical Process
    (2022-01-01)
    Wechprasit, Tirapat
    ;
    Kansaard, Thanaphon
    ;
    Bootchanont, Atipong
    ;
    Pecharapa, Wisanu
    In this work, Mn-incorporated BiVO<inf>4</inf> nanoparticles with different Mn contents (0–5%) were synthesized by one-step sonochemical process. Structural phase of Mn-incorporated BiVO<inf>4</inf> nanoparticles was extensively carried out by X-ray diffraction technique. The XRD results show that the structural phase of BiVO<inf>4</inf> belongs to the monoclinic principal structure while the secondary phases of MnO, Mn<inf>2</inf>O<inf>3</inf>, and Mn<inf>3</inf>O<inf>4</inf> structures are noticed in Mn-loaded samples. Chemical bondings of Mn-incorporated BiVO<inf>4</inf> nanoparticles were characterized with Raman spectroscopy. Relevant chemical bondings confirm the existence of VO<inf>4</inf><sup>3−</sup> tetrahedron and the V–O band by Raman spectra. Diffuse reflection spectroscopy and FE-SEM were employed to examine their optical and morphological properties, respectively. The results indicate that the incorporation of Mn can induce the red-shift of optical absorption edge in visible range, which can decrease the optical band gap of BiVO<inf>4</inf>. Morphology of all samples demonstrates the difference in shape of the compounds with the incorporation of Mn contents. Oxidation number and local structure of Mn-incorporated BiVO<inf>4</inf> nanoparticles were investigated by X-ray absorption spectroscopy. XAS results demonstrate that oxidation number of all elements correspond to Mn<sup>2+</sup>/Mn<sup>3+</sup>, Bi<sup>3+</sup>, and V<sup>5+</sup> ions. The normalized Mn K-edge XANES spectra suggest that Mn atoms would not locate at the local site of Bi or V in BiVO<inf>4</inf> crystal because the specific feature of experimental spectra are inconsistent with simulated spectra, which is corresponded to XRD results indicating the formation of Mn-based oxide structures with various oxidation states.
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    Effect of Ultrasonic Irradiation Time on Physical Properties and Photocatalytic Performance of BiVO4 Nanoparticles Prepared via Sonochemical Process
    (2021-01-01)
    Kansaard, Thanaphon
    ;
    Bangbai, Chatpong
    ;
    Jayasankar, C. K.
    ;
    Pecharapa, Wisanu
    Currently, photocatalyst materials have gained considerable attraction because of very rich economic performance of decomposition of highly toxic organic compound to lower toxic composition. The effort of this work was paid to study the effect of sonochemical ultrasonic irradiation time on the relevant properties of visible-light-driven bismuth vanadate (BiVO<inf>4</inf>) photocatalyst without any further thermal treatment process. The chemical bonding of BiVO<inf>4</inf> nanopowder was investigated by Fourier transform infrared (FTIR) and Raman spectrometer technique. Meanwhile their structure was characterized by X-ray diffraction technique (XRD). Field emission scanning electron microscope (FE-SEM) was used to observe particle morphology and chemical compositions was investigated by Energy-dispersive X-ray spectroscopy (EDX). Photocatalytic performance of BiVO<inf>4</inf> nanopowder was studied by decomposition of organic dye as organic pollutant model using visible light to excite photocatalyst materials. It was found that sonochemical irradiation time supplied during chemical process can effectively expedite the formation of BiVO<inf>4</inf> nanoparticle. The optimized condition to obtain the product with enhanced photocatalytic performance of 60% decomposition is achieved as the sample was prepared at 40 min ultrasonic irradiation.
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    Characterization of BiVO4 nanoparticles prepared by sonochemical process
    (2019-11-18)
    Kansaard, Thanaphon
    ;
    Pecharapa, Wisanu
    Nowadays, environment highly encounters various pollutants including toxic gases, organic volatiles and water pollutant. Many scientists have taken the effort to reduce or eliminate pollutant using photocatalytic materials. Due to good ferroelectric property in ferroelastic crystal as a result of the reduction in symmetry between the paraelastic and ferroelastic phases, it makes bismuth vanadate (BiVO<inf>4</inf>) one of attractive ferroelectric materials. In addition, BiVO<inf>4</inf> with low optical band gap could be activated by visible light illumination so that it would be a potential candidate as a visible light driven photocatalyst. This work was carried out to synthesize BiVO<inf>4</inf> nanoparticles by simple but effective method via sonochemical process through chemical route assisted by ultrasonic irradiation. The crystalline structure and surface morphologies of the synthesized products were observed by X-ray diffraction technique and Scanning Electron Microscope, respectively. Raman spectroscopy and Fourier Transform Infrared spectroscopy were used to approve the BiVO<inf>4</inf> chemical bonding and relevant crystalline formation. Photocatalytic activity was studied by mean of the degradation of organic dye assigned as organic compound under visible light irradiation.