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SrBi4Ti4O15 is one of four-layered Aurivillius compound family member that can be used as photocatalyst material that works in the violet light region. To expand its work function range can be conducted by doped with metal elements to SrBi4Ti4O15 as results reduced its band gap energy. In this research, we synthesized vanadium doped SrBi4Ti4O15 (SrBi4Ti4-nVnO15 (n= 0, 0.05, 0.1, and 0.15)) by molten salt method (used KCl salt). The diffractogram sample showed that the target compounds SrBi4Ti4-nVnO15 (n= 0, 0.05, 0.1, and 0.15) had been successfully synthesized with the space group A21am without impurities. The SEM micrographs showed the particle shape of SrBi4Ti4-nVnO15 (n= 0, 0.05, 0.1, and 0.15) was plate-like (sheets) and V dopant did not cause agglomeration. The result of Kubelka-Munk equation calculation showed that the V dopant can reduced the band gap energy value from 3.04 eV (408 nm) to 2.84 eV (437 nm)

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<p class="02abstracttext"><span lang="PT-BR">Iron lathe waste powder has the potential as a raw material in the synthesis of hematite pigments. Hematite pigments have many advantages, one of which is anti-swelling properties that can maintain the dimensions of wood. Hematite pigment synthesis was carried out using the precipitation-sonication method. The precipitation stage uses an ammonium hydroxide solution as a precipitating agent. Stages of sonication using the PEG-6000 template were performed at different times were 30, 45, and 90 minutes then calcined at 750 ° C for 3 hours. The samples were characterized by X-ray diffraction (XRD), color reader, and scanning electron microscope-energy dispersive <br /> X-Ray (SEM-EDX). The result confirmed that a ferrihydrite phase obtained after the precipitation process and transform into hematite after the calcination process with the highest degree of crystallinity for 90-minute sonication. From a color reader, the brightness and redness degrees decrease with increasing time. Scanning electron microscope results illustrated that the morphology was not uniform with the particle size getting smaller with increasing sonication time. The EDX results show that hematite pigments still contain impurities such as carbon. The swelling test indicated that the highest stability in hematite-pigmented wood increased as increasing in the weight of pigment.</span></p>

<p>One of the potential properties of the Aurivillius compound is photocatalyst. The four-layered Aurivillius compound BaBi₄Ti₄O₁₅ has a bandgap energy of 3.2 eV caused having work function in the UV light area. The strategy to decrease the bandgap energy is doping with metal elements such as vanadium (V). In this research, vanadium-doped BaBi₄Ti₄O₁₅ (BaBi₄Ti_4-<em>_x</em>V<em>_x</em>O₁₅) (<em>x</em>= 0, 0.05, 0.1, and 0.15)) compounds was synthesized through the molten KCl salt method. The diffractogram samples showed that BaBi₄Ti_4-<em>_x</em>V<em>_x</em>O₁₅ (<em>x</em>= 0, 0.05, 0.1, 0.15) had been successfully obtained but still found impurities  TiO₂ (rutile phase) at <em>x</em>= 0, 0.05, 0.1, 0.15, and Bi₄V₂O₁₁ at <em>x</em>= 0.15. The SEM image showed that the particle has plate-like morphology. The UV-Vis DRS spectrum showed that vanadium-doped BaBi₄Ti₄O₁₅ has lower bandgap energy.</p>