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Dry-co-grinding of doped TiO2 with nitrogen, silicon or selenium for enhanced photocatalytic activity under UV/visible and visible light irradiation for environmental applications
摘要： TiO2 doped with nitrogen (N), silicon (Si), or selenium (Se) (N-TiO2, Si-TiO2, and Se-TiO2) were obtained by the integrated sol-gel and solvothermal method with short time of crystallization and low temperature. The UV/visible and visible light absorption and photocatalytic activity of these doped TiO2 materials were improved by a dry-co-grinding process with a short grinding time and low rotational speed (30 min at 200 rpm) to obtain N-TiO2/Si-TiO2 and N-TiO2/Se-TiO2 catalysts. The materials were characterized by XRD, Raman, BET surface area and porosity, XRF, SEM, TEM, FTIR-ATR, and UV/vis-DRS analyses. The photocatalytic activity of these materials was evaluated by the degradation of phenol under UV/visible and visible light irradiation. The integrated sol-gel and solvothermal methods with short time of crystallization (2 h) and low temperature (225 °C), and the dry-co-grinding process during 30 min at 200 rpm led to materials (N-TiO2/Si-TiO2 and N-TiO2/Se-TiO2) with higher specific surface area, a reduction in the band gap value, and an enhancement of the absorption in the visible light spectrum. Moreover, N-TiO2/Si-TiO2 and N-TiO2/Se-TiO2 exhibited higher photocatalytic activities for degradation of phenol under UV/visible and visible light irradiation than those obtained with the doped TiO2, synthesized TiO2 or TiO2 P25.
关键词： Doping TiO2,Titanium dioxide,Sol-gel,Co-grinding process,Solvothermal
更新于2025-09-10 09:29:36
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Assembly of surface-defect single-crystalline strontium titanate nanocubes acting as molecular bricks onto surface-defect single-crystalline titanium dioxide (B) nanorods for efficient visible-light-driven photocatalytic performance
摘要： Ti3+ self-doped single-crystalline SrTiO3(cid:1)x nanocubes acting as molecular bricks are successfully assembled onto Ti3+ self-doping single-crystalline TiO2(cid:1)x(B) nanorods through an effortless two-step hydrothermal process coupled with an in situ solid-state chemical reduction method. SrTiO3(cid:1)x nanocubes act as molecular bricks, which are uniformly assembled onto the surface of TiO2(cid:1)x(B) nanorods due to lattice matching. The band gap of the resultant SrTiO3(cid:1)x/TiO2(cid:1)x(B) sample is (cid:3)2.97 eV, which exhibits excellent photocatalytic performance for the reduction of Cr(VI) and hydrogen production under visible light. The apparent rate constant k value for the photocatalytic reaction of SrTiO3(cid:1)x/TiO2(cid:1)x(B) for Cr(VI) reduction is (cid:3)8 times higher than that of white TiO2(B). The photocatalytic hydrogen production rate for SrTiO3(cid:1)x/TiO2(cid:1)x(B) is (cid:3)160.2 lmol g(cid:1)1 h(cid:1)1, which is (cid:3)5 times higher than that of white TiO2(B). The enhanced photocatalytic activity can be considered to be caused by a synergetic effect of heterojunction formation and the introduction of Ti3+ self-doping, which can not only facilitate the separation of photogenerated charge carriers between TiO2(cid:1)x(B) and SrTiO3(cid:1)x, but also broaden the photoresponse from the UV to visible-light region.
关键词： Photocatalysis,Heterojunction,Ti3+ self-doping,TiO2(B),SrTiO3
更新于2025-09-10 09:29:36
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Solution combustion synthesis and characterization of phosphorus doped TiO2–CeO2 nanocomposite for photocatalytic applications
摘要： Phosphorus doped TiO2-CeO2 nanocomposite (P-TiO2-CeO2) was synthesized by solution combustion method. The prepared sample has been heated at di?erent temperatures and characterized by X-ray di?raction (XRD), scanning electron microscopy (SEM), UV–vis absorption spectra, X-ray photoelectron spctroscopy (XPS). XRD analysis reveals the retarded phase transition by increased thermal stability due to phosphorus doping. FE-SEM shows the porous structure of the sample. The absorption edge of the P/TiO2-CeO2 nanocomposite exhibits redshift with increasing heating temperature with its value around 2.93 eV, 2.90 eV and 2.89 eV at 400 °C, 500 °C and 600 °C respectively. From the observed P2p XPS peak, it is con?rmed that the doped phosphorus enters substitutionally into Ce4+/Ti4+ site, which can play an important role in the photocatalytic activity of the sample. The binding energy of Ti 2p XPS peak increases slightly from 458.5 eV to 458.8 eV due to interaction between titanium and cerium.
关键词： Phosphorus doping,TiO2,CeO2,XPS,TiO2-CeO2 nanocomposite
更新于2025-09-04 15:30:14
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Photocatalytic activity of gadolinium doped TiO <sub/>2</sub> particles for decreasing heavy metal chromium (VI) concentration
摘要： Titanium dioxide (TiO2) is among the most potential photocatalyst. However, TiO2 only works under UV light due to the relatively wide band gap energy. To overcome this, TiO2 is infiltrated (doped) by rare earth elements such as gadolinium (Gd). TiO2 was synthesized using sol gel method, while Gd/TiO2 photocatalyst was synthesized by the mixing methods of sol-gel and impregnation. The crystals are then characterized using XRD and SEM-EDX. The XRD diffractogram demonstrated that the crystallinity synthesized of TiO2 had an anatase structure similar to the structure of anatase P-25 as references. The SEM-EDX showed that Gd ion could not enter the crystal lattice, but only dispersed on the surface of TiO2 particles. The optimum result of decreased Cr(VI) concentration was reported using Gd/TiO2 1% w/w by a decrease of up to 94%, after irradiated with ultraviolet for one hour.
关键词： sol-gel method,gadolinium doping,TiO2,Cr(VI) concentration,photocatalyst
更新于2025-09-04 15:30:14