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NH2-MIL-125(Ti)/TiO2 Nanorod Heterojunction Photoanodes for Efficient Photoelectrochemical Water Splitting
摘要： A photoactive amine-functionalized Ti metal-organic framework (MOF) (MIL(125)-NH2(Ti)) layer is uniformly coated on vertically ordered TiO2 nanorods (NRs) via a facile hydrothermal reaction, and the performance of the heterojunction photoanode in photoelectrochemical (PEC) water splitting is studied. The photocurrent density of the MIL(125)-NH2/TiO2 NRs reaches 1.63 mA/cm2 at 1.23 V vs. a reversible hydrogen electrode under AM 1.5 G simulated sunlight illumination, which is ~2.7 times higher than that of pristine TiO2 NRs. The incident photon-to-electron conversion efficiency of the MIL(125)-NH2/TiO2 NRs improves significantly at λmax = 340 nm, implying the promotion of water oxidation through efficient light absorption and charge separation. The enhancement of the PEC activity in the TiO2 NRs caused by an MIL(125)-NH2 coating is discussed in relation to the surface area and elongated configuration of the TiO2 NRs, the band gap of MIL(125)-NH2(Ti), and the type (II) heterojunction. This study demonstrates the rational design of heterojunctions between the semiconductor and the MOF, which paves the way for new facile and general approaches to achieve a high efficiency in water splitting.
关键词： TiO2 nanorod,Photoelectrochemical water splitting,Photoanode,MIL(125)-NH2,Hydrothermal reaction
更新于2025-09-09 09:28:46
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Cotton fabric finished by PANI/TiO2 with multifunctions of conductivity, anti-ultraviolet and photocatalysis activity
摘要： Polyaniline/titanium dioxide (PANI/TiO2) were co-doped with sulfosalicylic (SSA) and sodium dodecyl benzene sulfonate (SDBS) and then deposited onto the surface of cotton fabrics in one-step in-situ polymerization. PANI/TiO2 composites were confirmed by Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), while the surface morphologies of the cotton fabrics were observed by field emission scanning electron microscopy (FESEM). The conductivity of prepared PANI/TiO2/cotton composites was measured by four-probe method and results showed that it decreased slightly with the increase of TiO2 concentration. The conductivity would be up to 8.8 S/cm at concentration of TiO2 4 g/L. The UPF value of PANI/TiO2/cotton composites was significantly enhanced, even if after washing for 10 times. The photocatalytic results showed that absorption and degradation efficiency of PANI/TiO2/cotton composites to rhodamine B (RHB) could reach up to 87.67%, which might be due to the synergistic effects of PANI and TiO2.
关键词： Conductivity,Cotton,Anti-ultraviolet,Polyaniline,TiO2,Photocatalysis activity
更新于2025-09-09 09:28:46
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Direct nanocrystallite size investigation in microstrained mixed phase TiO2 nanoparticles by PCA of Raman spectra
摘要： Mixed phase anatase and rutile TiO2 nanoparticles (30-67 % R/A) have been synthesized by single step laser pyrolysis. Parallel studies by XRD and Raman spectroscopy suggested possible deforming microstress inside certain samples, due to boundary interactions between neighbouring nanocrystallites in nanoparticles, phase instabilities and/or O/C contents. Microstress in nanoparticles supports anatase phase stability in competition with rutile phase. Williamson-Hall plot was used to evaluate crystallite size and strain. A tensile global microstrain in anatase crystallites, was observed for elevated C content titania nanoparticles, together with compressive microstrain in crystallites within O deficient TiO2 nanoparticles. XPS and TEM characterization opens insights into the processes behind this type of behaviour. Principal Component Analysis of Raman spectra was applied for batch auto-characterization of mixed phase nanoparticles, with emphasis upon the method ability to simultaneously appreciate crystallite size for both anatase and rutile phase. The method focuses on covariational matrix of multiple samples Raman spectra. It provides results in good agreement with XRD calculated crystallite dimensions for unstrained titania, while for samples with microstrains it returns the size closer to the one predicted by Williamson-Hall plot.
关键词： Microstrain,Anatase,Principal Component Analysis (PCA),Raman Spectroscopy,Williamson-Hall,Rutile,TiO2 nanoparticles
更新于2025-09-09 09:28:46
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Halloysite based nanocomposites and photocatalysis: A Review
摘要： Heterogeneous photocatalysis is an e?cient, relatively cheap and environmentally friendly technology for decomposing various organic and air pollutants. Halloysite is a natural clay mineral usually in the form of nanotubes that has many applications as well as potential uses including photocatalysis. In this paper the photocatalytic activities of halloysite-based nanocomposites in combination with various photocatalysts that have been synthesized and tested in decomposing organic and air pollutants are reviewed. Many photocatalysts have been synthesized and among them TiO2 in the form of anatase, or rutile, or a mixture of both is the most common photocatalyst due to its e?ectiveness and low cost. Researches by many investigators are summarized and discussed. The possibilities and limitations of halloysite-based nanocomposites for future applications are also discussed and new ?elds of research are proposed. It is suggested that Halloysite-based nanocomposites are more promising in positively charged organic substrates like tetracycline and Rhodamine B where the organic pollutant is attracted by halloysite's negatively charged external surfaces close to the photocatalysts, than neutral like paracetamol or negatively charged which that attraction does not occur.
关键词： Azo dyes,Halloysite nanocomposite,Halloysite,TiO2,VOCs,Heterogeneous catalysis,Air pollutants,Photocatalysis
更新于2025-09-09 09:28:46
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Tuning the Porosity of TiO2 Nanoparticles via Surfactant-Templated Aerosol Process for Enhanced Photocatalytic Reactivity
摘要： In this work, we fabricated crystallite solid and porous TiO2 nanoparticles (NPs) using a surfactant-templated aerosol process. Specifically, Brij-58 surfactant was employed as a template in TiO2 matrix. The porosity of TiO2 NPs was controlled by varying the amount of Brij-58. The effect of TiO2 porosity on the photocatalytic reactivity was systematically examined. As a result, the highly porous TiO2 NPs exhibited much better photocatalytic reactivity than the low porosity TiO2 NPs. This suggests that the particle size, crystallite structure, and specific surface area play an important role in enhancing the photocatalytic reactivity of the TiO2 NPs.
关键词： surfactants,Aerosol process,photocatalysts,porous TiO2 nanoparticles,specific surface area
更新于2025-09-09 09:28:46
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Ultrasound-assisted successive ionic layer adsorption and reaction synthesis of Cu2O cubes sensitized TiO2 nanotube arrays for the enhanced photoelectrochemical performance
摘要： In this paper, Cu2O cubes with high photoelectrochemical activities were deposited on the surface of TiO2 nanotube arrays by the ultrasound-assisted successive ionic layer adsorption and reaction (SILAR) method. The elemental composition and morphology were characterized by XPS and SEM. The TiO2 NTs/Cu2O showed excellent photoelectric conversion and photoelectrocatalytic (PEC) removal of organic dyes and Cr(VI). The results confirmed that the SILAR deposition cycle greatly influenced the visible light response and PEC properties, and the TiO2 NTs/Cu2O (6) prepared with 6 SILAR cycles showed the optimal visible light photocurrent (1.08 mA/cm2), visible light photovoltage (-0.044 V/cm2), solar PEC degradation efficiencies of MO (77.62%), RhB (61.83%) and MB (98.30%), and PEC reduction of Cr(VI) (97.16%). The TiO2 NTs/Cu2O photoelectrodes would show prospective applications in solar cells and waste-water treatment due to the significantly enhanced photoelectrochemical performance.
关键词： Photocatalysts,TiO2 nanotube arrays,Cu2O cubes,SILAR,Photocurrent
更新于2025-09-09 09:28:46
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Effects of Fe and Ni co-doping on the Optical Properties of TiO <sub/>2</sub> Thin Films
摘要： In this work, the effects of Fe/Ni co-doping on structural and optical properties of TiO2 thin films were investigated by the X-ray diffraction, scanning electron microscope and UV-visible spectroscopy. The optical properties of transmittance, extinction coefficient, refractive index, real and imaginary parts of dielectric constant of the thin films, prepared by spray pyrolysis, revealed that the absorption in visible region increases due to the influence of Fe/Ni co-doping. The widening of the gap energies is observed as a result of doping. The increased optical gap as a consequence of doping can be explained by decreasing the size of nanoparticles, as confirmed by SEM and increasing the formation of oxygen vacancies as a result of Ni2+ substitution to Ti4+ and appearance of the Burstein-–Moss effect.
关键词： Optical properties,Gap energy,Fe and Ni,Co-doped TiO2
更新于2025-09-09 09:28:46
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Boosting the efficiency of carbon-based planar CsPbBr3 perovskite solar cells by a modified multistep spin-coating technique and interface engineering
摘要： All-inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted tremendous attentions in the photovoltaic field these days in view of their outstanding stability, especially thermal stability. However, the bromide-rich perovskite, such as CsPbBr3, always suffer from a low phase-purity and poor morphology synthesized by traditional two-step deposition route. Herein, we demonstrate a facile multistep spin-coating strategy to fabricate high-quality CsPbBr3 films on the low-temperature processed compact TiO2 (c-TiO2) electron transport layer (ETL) of the carbon-based PSCs. As-prepared films exhibit more homogeneous with higher CsPbBr3-phase purity and larger average grain sizes up to 1 μm, compared to those prepared through traditional two-step deposition process. The champion power conversion efficiency (PCE) of the planar CsPbBr3 PSC is boosted from 7.05% to 8.12%, getting an increase by 15.2%, due to the increased crystallinity and light-harvesting ability as well as reduced trap states of the CsPbBr3 film. To further enhance the device performance, a SnO2 thin layer with much higher carrier mobility than TiO2 is introduced to passivate the c-TiO2 ETL. It is found that the SnO2 layer can not only improve the surface morphology of the ETL, but also reduce the current shunting pathways in the c-TiO2. The TiO2/SnO2 bilayered ETL possesses a superior electron extraction capability, beneficial to the charge transport and suppression of the interfacial trap-assisted recombination. The best-performing TiO2/SnO2-based CsPbBr3 PSC delivers an excellent fill factor of 0.817 and a high PCE of 8.79%, which is the highest efficiency for planar CsPbBr3 PSCs reported to date. More importantly, the unencapsulated all-inorganic PSCs show a promising humidity and thermal stability with no decline in efficiency when stored in ambient air at room temperature (25 oC) for over 1000 h and 60 oC for one month, respectively. Our work pave the ways for practical applications of cost-effective, highly efficient and stable all-inorganic PSCs.
关键词： carbon-based,TiO2/SnO2,low cost,CsPbBr3,multistep spin-coating,high efficiency and stability
更新于2025-09-09 09:28:46
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Comparative Study on The Photocatalytic Hydrogen Production from Methanol over Cu-, Pd-, Co- and Au-Loaded TiO <sub/>2</sub>
摘要： Photocatalytic hydrogen production from a methanol-water solution was investigated in a semi-continuous reactor over different metal-loaded TiO2 catalysts under UltraViolet (UV) light irradiation. The catalysts were mainly prepared by the incipient wetness impregnation method by varying the metal weight ratio in the range of 1-10 wt%. The effects of metal loading and H2 pre-treatment on the photocatalytic activity were investigated. In addition, the activity of the catalysts was also compared with a reference Au-TiO2 catalyst from the World Gold Council (WGC). The photocatalysts were characterized by using X-Ray Diffraction (XRD) and N2 physisorption before and after the activity measurements. The photocatalytic activity decreased in the order of Pd > Au > Cu > Co in the comparative study of Cu-TiO2, Co-TiO2, Au-TiO2 and Pd-TiO2. Optimum hydrogen evolution was achieved with 5 wt% Pd-TiO2 and 5 wt% Cu-TiO2.
关键词： Metal loading,UV light irradiation,Photocatalytic hydrogen production,Methanol,TiO2
更新于2025-09-09 09:28:46
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Photoactivity of Ag/TiO2 Microsphere by One-Step Hydrothermal Method
摘要： Ag/TiO2 microsphere photocatalyst was prepared via one step hydrothermal method and prepared catalyst was used for photodegradation of rhodamine B under visible light. The Ag/TiO2 catalyst was characterized through X-ray diffraction (XRD) and scanning electron microscope (SEM). The results showed Ag was uniformly distributed in the titanium matrix. The 6 % Ag doped TiO2 catalyst had the higher photoactivity than other proportion to degrade rhodamine B 86.6 % within 60 min under visible light. The Ag doped TiO2 also had the good activity under solar light cut off UV light.
关键词： Ag doped TiO2,Photodegradation,Hydrothermal method,Microsphere
更新于2025-09-09 09:28:46