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Enhanced photocatalytic activity of a mesoporous TiO2 aerogel decorated onto three-dimensional carbon foam
摘要： TiO2/carbon composites have been well studied as solar-light photocatalysts because they combine the advantages of TiO2 (good photocatalytic activity) and carbon (enhanced charge carrier separation). Mesoporous TiO2 aerogels are fragile by nature and the addition of free-standing three-dimensional (3D) porous carbon foam (CF) not only makes it easy for separation and collection after photocatalytic treatment but also acts as a scaffold for the long-term application of TiO2 aerogels in the photocatalysis. Hence, recent reports have shown that mesoporous TiO2 aerogel/CF composites synthesized by the carbonization of a polymer followed by using the sol-gel method are significant for use in photocatalysis applications. In addition, the 3D macroporous CF not only acts as a support for TiO2 aerogels but also improves the efficiency of light use and extends the photoresponse of TiO2 to the visible region. The TiO2 aerogel was homogeneously distributed onto the 3D CF because of the vacuum infiltration used during the synthesis of the composites. The simulated solar-light irradiated photocatalytic degradation of Rhodamine B organic pollutant was used to evaluate the TiO2 aerogel/CF composite catalysts, which was higher than with a pristine TiO2 aerogel. This facile synthesis approach for 3D foam type TiO2/carbon composites could be useful in the treatment of wastewater.
关键词： anatase,Mesoporous TiO2 aerogel,photocatalysis,sol-gel method,carbon foam
更新于2025-09-23 15:19:57
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Synthesis and photocatalytic properties of electrodeposited bismuth oxyiodide on rutile/anatase TiO<sub>2</sub> heterostructure
摘要： Bismuth oxyiodide (BiOI) modified rutile/anatase TiO2 heterostructure was fabricated by a three-step process. Anatase TiO2 sheet was first formed on fluorine-doped tin oxide (FTO) glass substrate. Rutile TiO2 nanorods were then grown on anatase TiO2 sheet via a hydrothermal process. BiOI was finally coated on the surface of hierarchical TiO2 film using an electrochemical deposition method. Photocatalytic tests on degradation of methylene blue (MB) in water indicated that BiOI modified hierarchical TiO2 film possessed an excellent photocatalytic activity superior to those of the monophase anatase and rutile TiO2 films, commercial P25 film and hierarchical TiO2 film. The enhanced photocatalytic performance was probably attributed to the synergetic effects of strong visible light absorption and formation of heterojunctions by the interfaces in the BiOI / rutile TiO2 / anatase TiO2 / FTO structure, which promoted efficient separation of photoinduced electron-hole pairs. In addition, the main active species during the degradation were confirmed to be hydroxyl radicals and superoxide radicals.
关键词： hierarchical rutile/anatase TiO2,nanostructure,film,electrodeposition,charge carrier separation,visible absorption,BiOI
更新于2025-09-19 17:15:36
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Supercritical CO <sub/>2</sub> -assisted deposition of NiO on (101)-anatase-TiO <sub/>2</sub> for efficient facet engineered photocatalysts
摘要： NiO/(101)-anatase-TiO2 heterostructure nanoparticles were synthesized by depositing NiO onto the (101) facet of anatase crystals via the supercritical fluid chemical deposition (SFCD) route. Thorough characterization experiments performed by various techniques (XRD, UV-Vis DRS, N2 sorption, HR-TEM, EDX, and XPS) indicate that the SFCD method allowed a good dispersion of NiO onto the TiO2 nanoparticles for NiO amounts below 2 wt%. Compared to pure TiO2, the 0.1–1 wt% NiO–TiO2 nanocomposites showed enhanced photocatalytic properties for methylene blue (MB) and methyl orange (MO) decomposition under UV light irradiation, the 0.25 wt% NiO–TiO2 system leading to the highest efficiencies. The photocatalytic properties were then rationalized in terms of the acidic properties and electronic structures of the NiO–TiO2 nanocomposites. This higher photocatalytic activity was mainly related to the heterocontact at the interface of the NiO–TiO2 crystallites and to the enhanced reaction rates at the NiOx surface.
关键词： anatase-TiO2,Supercritical CO2,photocatalysis,NiO deposition,facet engineering
更新于2025-09-19 17:15:36
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Solution-Processed Anatase Titania Nanowires: From Hyperbranched Design to Optoelectronic Applications
摘要： The utilization of solar energy and the development of its related optoelectronic devices have become more important than ever. Solar cells or photoelectrochemical (PEC) cells that require the design of light harvesting assemblies for efficiently converting solar light into electricity or solar fuels are of particular interest. Semiconductor TiO2, serving as the photoelectrode for photovoltaic devices (e.g., dye- or quantum dot-sensitized solar cells (DSSCs/QDSSCs) or perovskite solar cells (PSCs)) and PEC cells, has aroused intense research interest owing to its inherent characteristics of wide band gap and promising optical and electrical properties. TiO2 nanowires (TNWs) have been widely used in optoelectronic devices due to their unique 1D geometry and salient optical and electrical properties. However, the insufficient surface area resulting from the relatively large diameter of NWs and considerable free space between adjacent NWs restricts their optoelectronic performance. Hence, it is desirable to explore every feasible aspect of TNWs in terms of structural design and optical management, aiming to further improve the performance of optoelectronic devices. In this Account, we present a brief survey of strategies for designing branched or hyperbranched TNW-based photoelectrodes and their applications in solar cells and PEC cells. The general strategies (e.g., alkaline/acid hydrothermal method, lift-off transfer, and self-assembly approach) are discussed to address the challenges associated with fabricating TNWs on transparent conducting oxide (TCO) substrates. A series of strategies to fabricate judiciously designed 3D branched array architectures, including length tuning and sequential surface branched or hyperbranched modification, are proposed. The versatile implantation of the TNWs onto other backbones (nanosheets, nanotubes, hollow spheres, or multilayered electrodes) and substrates (fiber-shaped metal wire or mesh, flexible metal foil, or plastic sheet) is demonstrated to construct a new class of the TNW-embedded composite electrode materials with desired morphological characteristics and optoelectronic properties, for example, favorable energy level alignment for cascade charge transfer and rational homogeneous/heterogeneous interfacial engineering. The functionalities of TNW-based electrodes include enlarged surface area and superior light scattering for maximized light harvesting, as well as facilitated charge transport and suppressed charge recombination for enhanced charge collection, which are promising in optoelectronic fields such as solar cells, photocatalysis, and PEC cells. Beyond TNWs, one can also integrate other types of semiconductor (e.g., Fe2O3 or WO3) NWs into rationally designed structures for preparing novel photocatalytic materials with panchromatic absorption, efficient charge transfer, and excellent catalytic properties. Finally, an insightful perspective for rational design of advanced NW-based materials is provided.
关键词： Solar cells,Hyperbranched design,Anatase titania nanowires,Photoelectrochemical cells,Optoelectronic applications,Solution-processed
更新于2025-09-19 17:15:36
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Design of Multifunctional Titania-Based Photocatalysts by Controlled Redox Reactions
摘要： This work aims at the preparation of multifunctional titania-based photocatalysts with inherent capabilities for thermal co-activation and stabilisation of anatase polymorph, by designing the phase composition and microstructure of rutile-silicon carbide mixture. The processing involved a conventional solid state route, including partial pre-reduction of rutile by SiC in inert Ar atmosphere, followed by post-oxidation in air. The impacts of processing conditions on the phase composition and photocatalytic activity were evaluated using Taguchi planning. The XRD studies confirmed the presence of rutile/anatase mixtures in the post-oxidised samples. The results emphasise that pre-reduction and post-oxidation temperatures are critical in defining the phase composition, while post-oxidation time is relevant for the photocatalytic performance. Microstructural studies revealed the formation of core-shell particles, which can suppress the photocatalytic activity. The highest apparent reaction rate of the photodegradation of methylene blue was observed for the sample pre-reduced in Ar at 1300°C for 5 h and then calcined in air at 400°C for 25 h. Though its performance was ~1.6-times lower than that for the same amount of nanostructured industrial P25 photocatalyst, it was achieved in the material possessing 2–3 times lower surface area and containing ~50 mol% of SiO2 and SiC, thus demonstrating excellent prospects for further improvements.
关键词： silicon carbide,Taguchi plan,photocatalysis,redox reaction,anatase,TiO2
更新于2025-09-19 17:13:59
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High-Efficiency Perovskite Solar Cells Enabled by Anatase TiO2 Nanopyramid Arrays with Oriented Electric Field
摘要： One-dimensional (1D) nanostructured oxides have been proposed as excellent electron transport materials (ETMs) for perovskite solar cells (PSCs), but this has not yet been demonstrated experimentally. Here, we exploit a facile hydrothermal approach to grow highly oriented anatase TiO2 nanopyramid arrays and further demonstrate their advantages for application in PSCs. The oriented TiO2 nanopyramid arrays afford sufficient contact area for electron extraction and increase light transmission. Moreover, the nanopyramid array/perovskite system exhibits an oriented electric field that can increase charge separation and accelerate charge transport, thereby suppressing charge recombination. As a result, the anatase TiO2 nanopyramid arrays-PSCs deliver a champion power conversion efficiency of ~22.5%, which is the highest PCE reported thus far for PSCs consisting of 1D ETMs. This work demonstrates that the rational design of 1D ETMs can achieve PSCs that perform as well as typical mesoscopic and planar PSCs.
关键词： Anatase TiO2,Electric field distribution,Perovskite solar cells,One-dimensional nanostructures,Nanopyramid arrays
更新于2025-09-19 17:13:59
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Role of Modifying Photoanodes by Organic Titanium on Charge Collection Efficiency Enhancement in Dye‐Sensitized Solar Cells
摘要： Mesoporous TiO2 photoanodes are prepared by an electrophoretic deposition (EPD) method and applied in dye-sensitized solar cells (DSSCs). Pretreating an F-doped SnO2 coated glass (FTO) substrate and post-treating a TiO2 film to introduce an anatase TiO2 layer on the FTO and the TiO2 film, respectively, can greatly improve the power conversion efficiency (PCE) of a DSSC, which constitutes up 31% improvement compared with the untreated device. To disclose the mechanism for improvement, scanning electron microscopy, electrochemical impedance spectroscopy, open-circuit voltage decay, and photoluminescence spectra are investigated. It is proposed that the preformed compact TiO2 layer can suppress the back recombination by preventing direct contact between the electrolyte and the FTO substrate. Moreover, the compact TiO2 layer can reduce contact resistance between FTO and TiO2 particles. Further increased PCE by post-treatment is attributed to the promoted charge transfer efficiency. Both pre- and post-treating strategies can offer a reference to enhance the PCE for other porous film-based DSSCs, as well as promote the application of EPD in DSSCs.
关键词： photoanodes,anatase TiO2 layers,dye-sensitized solar cells,modify
更新于2025-09-16 10:30:52
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Hierarchically Anatase TiO2 microspheres composed of tiny octahedra used as mesoporous layer in perovskite solar cells
摘要： In this study, Hierarchically Anatase TiO2(HAT) Microspheres composed of tiny octahedra was prepared by hydrothermal method and introduced to perovskite solar cells(PSCs). Self-assembly linear units can provide better electronic transmission path in HAT.A power conversion efficiency of PSC based on HAT is 15.42%. Surface modification of the electron transport layer in perovskite solar cells has been proven to be one crucial strategy to improve the power conversion efficiency. Nb2O5, MgO and Al2O3 were deposited on the HAT surface, respectively. All of HAT films exhibit bigger electrons life span and suppressed charge recombination at the interface of TiO2 /perovskite films in the modified devices as well. As result, a campion power conversion efficiency of PSC based on Nb2O5@HAT could reach to 17.10%
关键词： Hierarchically Anatase TiO2,oxide electrode,Perovskite solar cell,Surface modification
更新于2025-09-16 10:30:52
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Synthesis of Na-, Fe-, and Co-promoted TiO$_{2}$/multiwalled carbon nanotube composites and their use as a photocatalyst
摘要： The use of multiwalled carbon nanotubes (CNTs) in sol-gel synthesized titanium dioxide (TiO 2) photocatalysts as templates was systematically studied. CNTs have high oxidative thermal stability and the controlled removal of CNTs can be achieved at lower temperatures under air (cid:13)ow by the use of Na, Fe, and Co as a catalyst. These catalysts helped to reduce the oxidation temperature of CNTs; thus anatase phase was achieved without signi(cid:12)cant sintering. The use of a promoter, heat treatment, and various heat treatment atmospheres was e?ective in speci(cid:12)c surface area, crystallinity, and photocatalytic activity against methylene blue (MB) degradation. While the speci(cid:12)c surface area of bare TiO 2 was 22 m 2 /g, after templating surface areas as high as 191 m 2 /g were obtained. For the photocatalytic characterization, with bare TiO 2 , the rate constant for MB decomposition was 0.81 h (cid:0)1 , and for CNT{TiO 2 it was 1.31 h (cid:0)1 . Moreover, after Na promotion, the rate constant increased to 1.85 h (cid:0)1 . The results showed that CNTs can be used as a template to tailor and improve the textural properties. Moreover, as a novel material, the Na promotion in CNT{TiO 2 samples showed the best photocatalytic activity by enhancing the interaction between TiO 2 and CNT surfaces.
关键词： anatase,Carbon nanotubes,TiO 2,doping,sol-gel,template,photocatalysis,composite
更新于2025-09-16 10:30:52
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Rapid Room-Temperature Synthesis of Mesoporous TiO2 Sub-Microspheres and Their Enhanced Light Harvesting in Dye-Sensitized Solar Cells
摘要： Submicron sized mesoporous spheres of TiO2 have been a potential alternative to overcome the light scattering limitations of TiO2 nanoparticles in dye‐sensitized solar cells (DSSCs). Currently available methods for the growth of mesoporous TiO2 sub‐microspheres involve long and relatively high temperature multi‐stage protocols. In this work, TiO2 mesoporous sub‐microspheres composed of ~5 nm anatase nanocrystallites were successfully synthesized using a rapid one‐pot room‐temperature CTAB‐based solvothermal synthesis. X‐Ray Diffraction (XRD) showed that the grown structures have pure anatase phase. Transmission electron microscopy (TEM) revealed that by reducing the surfactant/precursor concentration ratio, the morphology could be tuned from monodispersed nanoparticles into sub‐micron sized mesoporous beads with controllable sizes (50–200 nm) and with good monodispersity as well. The growth mechanism is explained in terms of the competition between homogeneous nucleation/growth events versus surface energy induced agglomeration in a non‐micelle CTAB‐based soft templating environment. Further, dye‐sensitized solar cells (DSSCs) were fabricated using the synthesized samples and characterized for their current‐voltage characteristics. Interestingly, the DSSC prepared with 200 nm TiO2 sub‐microspheres, with reduced surface area, has shown close efficiency (5.65%) to that of DSSC based on monodispersed 20 nm nanoparticles (5.79%). The results show that light scattering caused by the agglomerated sub‐micron spheres could compensate for the larger surface areas provided by monodispersed nanoparticles.
关键词： CTAB,light scattering,surfactant,titanium dioxide,dye‐sensitized solar cells,anatase
更新于2025-09-16 10:30:52