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A microfluidic all-vanadium photoelectrochemical cell with the N-doped TiO2 photoanode for enhancing the solar energy storage
摘要： In this work, the nitrogen-doped TiO2 photocatalyst is synthesized and applied in a microfluidic all-vanadium photoelectrochemical cell for enhancing the solar energy storage. The use of the nitrogen-doped TiO2 photoanode and the minimization design can ensure the visible-light response, increased specific surface area, vigorous pore structure and enhanced photon and mass transport as well as more uniform light distribution. Various characterizations are performed to evaluate the developed photocatalyst and microfluidic all-vanadium photoelectrochemical cell. The results confirm that the developed nitrogen-doped TiO2 photoanode can provide both the extended absorption spectrum and the small anatase crystal size as well as the obviously enlarged specific surface area with plentiful pore structure. Because of these merits, the microfluidic all-vanadium photoelectrochemical cell with the nitrogen-doped TiO2 photoanode yield the average photocurrent density of 0.103 mA/cm2 during the long-term operation, which is much higher than those with the un-doped TiO2 photoanode (0.086 mA/cm2) and commercial P25 TiO2 photoanode (0.073 mA/cm2), presenting 19.8% and 41% improvements, respectively. The results demonstrate not only the promotion of the vanadium reversible redox pairs conversion but also the inherently excellent stability by the nitrogen-doped TiO2 photoanode.
关键词： Photoanode,N-doped TiO2 photocatalyst,Conversion rate,Microfluidic all-vanadium photoelectrochemical cell,Solar energy storage
更新于2025-11-14 17:03:37
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Photocatalytic CO2 reduction on porous TiO2 synergistically promoted by atomic layer deposited MgO overcoating and photodeposited silver nanoparticles
摘要： In this work, a porous TiO2 photocatalyst derived from metal-organic framework MIL-125 was synthesized and tested for photocatalytic CO2 reduction with water. To improve the photocatalytic performance, innovative materials modifications were employed by decorating TiO2 with atomic layer deposited (ALD) MgO overcoating and photodeposited silver (Ag) nanoparticles at different orders: MgO deposition followed by Ag (i.e. Ag/MgO/TiO2), or Ag deposition followed by MgO (i.e. MgO/Ag/TiO2). The addition of Ag promoted transfer of photoinduced electrons, while the coating of an ultrathin MgO layer inhibited surface charge recombination and enhanced CO2 adsorption. The combination of MgO and Ag resulted in synergistic promotion on CO2 photoreduction greater than the sum of individual promotional effects. The Ag/MgO/TiO2 catalyst with 7 ALD-layers of MgO and 5% Ag was 14 times more active than the pristine TiO2 in terms of CO and CH4 production. In addition, the sequence of MgO/Ag decoration influenced the catalytic activity. The Ag/MgO/TiO2 catalysts were in general more active than the MgO/Ag/TiO2 counterparts, likely due to the different electron mobility and Ag nanoparticle distribution on the surface. This work for the first time reports the novel materials structure of ALD coated MgO and photodeposited Ag nanoparticles on TiO2, and it reveals the importance of optimizing materials morphology and structure to promote the catalytic activity.
关键词： CO2 photoreduction,magnesium oxide,silver nanoparticles,atomic layer deposition,porous TiO2
更新于2025-11-14 17:03:37
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Excellent catalysis of TiO2 nanosheets with high-surface-energy {001} facets on hydrogen storage properties of MgH2
摘要： Transition metal compound is one of the highly efficient catalysts in improving the reaction kinetics of hydrogen storage materials. Among all the transition metal, titanium and its compounds show great catalytic effect on magnesium hydride. In this paper, TiO2 nanosheets with exposed {001} facets were synthesized and doped into MgH2 for the first time. The TiO2 nanosheets (NS) doped MgH2 shows superior kinetic performance and lowest desorption temperature. The onset temperature of MgH2 + 5 wt% TiO2 NS to release hydrogen is 180.5 °C and the corresponding peak temperature is 220.4 °C, which are greatly lower than those of pure MgH2 and also distinctly lower than those of MgH2 + 5 wt% TiO2 nanoparticles (NP). For isothermal dehydrogenation analysis, the MgH2 + 5 wt% TiO2 NS can release 6.0 wt% hydrogen within 3.2 min at 260 °C and desorb 5.8 wt % hydrogen within 6 min at 240 °C. It is worth noting that the MgH2 + 5 wt% TiO2 NS can even release 1.2 wt% hydrogen at a temperature as low as 180 °C within 300 min. The hydrogenation kinetics of MgH2 + 5 wt% TiO2 NS is also greatly improved, which could absorb hydrogen within only a few seconds at the mild temperature. It can uptake 3.3 wt% hydrogen at 50 °C and 5.4 wt% at 100 °C within 10 s. It is demonstrated that the tremendous enhancement in reaction kinetics of MgH2 can be ascribed to the nanometer size and highly active {001} facets of anatase TiO2. The higher average surface energy can significantly reduce the hydrogen desorption activation energy of MgH2 to 67.6 kJ/mol, thus easily improves the hydrogen desorption properties.
关键词： Magnesium hydride,Hydrogen storage,Catalytic effects,crystal facets,TiO2
更新于2025-11-14 17:03:37
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Photocatalytic Degradation of Methylene Blue over TiO2 Pretreated with Varying Concentrations of NaOH
摘要： In this paper, different NaOH concentrations (2, 5, 10, and 15 M) were used to treat {001}TiO2. The effect of NaOH on the crystal structure, morphology, optical properties, light raw electronic-hole recombination, and degradation performance of {001}TiO2 on methylene blue were studied. The results demonstrate that rutile TiO2 appeared when the NaOH concentration was as high as 10 M, showing much better photolytic performance than others. As the concentration of sodium hydroxide increases, the morphology changes accordingly. The specific surface area increases and the optical electronic-hole recombination rate decreases. Radical scavenging tests showed that hydroxyl radical and hole are very important in photocatalysis.
关键词： NaOH concentration,radical scavenging,{001}TiO2,methylene blue,photocatalysis
更新于2025-11-14 17:03:37
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Synergistic effects and kinetics of rGO-modified TiO2 nanocomposite on adsorption and photocatalytic degradation of humic acid
摘要： Graphene oxide was prepared using the modified Hummers method and reduced graphene oxide (rGO) - titanium dioxide (TiO2) nanocomposite was synthesised using the one-step hydrothermal treatment. The synergistic effects on adsorption and photocatalytic properties of the rGO-TiO2 nanocomposite for the humic acid removal were systematically investigated. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman and infrared (IR) spectroscopy indicate that GO was partially reduced to reduced graphene oxide (rGO) in the hydrothermal synthesis process and anatase TiO2 nanoparticles uniformly grew on the surface of rGO. The photoelectron and photohole generated under visible light irradiation were effectively separated on the surface of rGO-TiO2. The rGO-TiO2 nanocomposite exhibited higher photocatalytic activity as a result of the synergistic effects of surface functional groups for adsorption and the excellent conductivity for photocatalytic reaction. The effect of rGO-TiO2 nanocomposite dosage, light intensity and system temperature on the removal of humic acid solution was investigated. The results show that the removal efficiency of humic acid increased with system temperature and light intensity. When the dosage of rGO-TiO2 nanocomposite was 1.2 g/L, the temperature, the light intensity and the pH of this system was 303 K, 4.37 Wm?2 and 7, respectively, the removal efficiency of humic acid reached 88.7% under visible light irradiation.
关键词： Synergistic effects,rGO,Humic acid,TiO2,Adsorption and photocatalysis
更新于2025-11-14 17:03:37
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2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterostructure for high photocatalytic activity
摘要： A novel 2D visible-light-driven TiO2@Ti3C2/g-C3N4 ternary heterojunction photocatalyst with modified interfacial microstructure and electronic properties was synthesized by ultrasonic-assisted calcination method. The remarkably active g-C3N4 could provide high productivity of photogenerated electrons and holes. Meanwhile, the O/OH-terminated Ti3C2 and by-product TiO2 could act as excellent supporters by migrating electrons in TiO2@Ti3C2/g-C3N4 hybrids. As a result, the highest photocatalytic activities in the degradation of aniline and RhB were increased to 5 and 1.33 times higher than that of pristine g-C3N4 under visible-light irradiation, respectively. Furthermore, we proposed that n–n heterojunction and n-type Schottky heterojunction were built up across their interfaces, which efficiently improve the transition of electrons and further promote the photocatalytic activity of TiO2@Ti3C2/g-C3N4 hybrids. More appealingly, all the results highlight that the environment-friendly TiO2@Ti3C2/g-C3N4 heterojunction hybrids would be desirable candidates for pollutants degradation.
关键词： 2D materials,photocatalytic activity,TiO2@Ti3C2/g-C3N4,ternary heterojunction,pollutants degradation,visible-light-driven
更新于2025-11-14 17:03:37
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Visible light-induced oxidation of aqueous arsenite using facile Ag2O/TiO2 composites: Performance and mechanism
摘要： Conversion of aqueous arsenite [As(III)] to less toxic arsenate [As(V)] is a critical step for the arsenic pollution remediation. In this study, Ag2O/TiO2 composites synthesized via the pH-induced precipitation method were employed into the photocatalytic oxidation of As(III) under visible light irradiation. X-ray diffraction, transmission electron microscope and X-ray photoelectron spectroscopy analysis verified the formation of Ag2O/TiO2 heterostructures. Compared to pure Ag2O and TiO2, the 30% Ag2O/TiO2 composite exhibited much higher photochemical reactivities for the oxidation of As(III) under visible light irradiation. Under the optimal conditions [pH=4.0, the photocatalyst dosage being 0.3 g L-1 and initial As(III) concentration being 10 mg L-1], the oxidation and removal percent of As(III) was 60.7% and 83.0% after reaction for 120 min, respectively. Moreover, the formation of Ag(0) over the surface of Ag2O by photo-induced electrons contributed to the high stability of Ag2O/TiO2 composite. It was also found that photo-generated holes and superoxide radicals played the predominant roles in the As(III) oxidation. The improved photocatalytic activities were attributed to the formation of the hetero-junctions between Ag2O and TiO2, the strong visible light absorption, and the high separation efficiency of photo-generated electron-hole pairs resulted from the Schottky barriers at the Ag-Ag2O interface.
关键词： visible light,arsenite oxidation,Ag2O/TiO2 composite,photocatalytic
更新于2025-11-14 17:03:37
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Synthesis of visible light responsive iodine-doped mesoporous TiO2 by using biological renewable lignin as template for degradation of toxic organic pollutants
摘要： The visible light responsive I-doped mesoporous TiO2 (I/TiO2-T) catalysts were synthesized by facile hydrolysis method with lignin as a template. The resulting I/TiO2-T catalysts synthesized from different amounts of I as a dopant and lignin as a template were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse spectroscopy (DRS), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL), and electrochemical impedance spectroscopy (EIS). The photocatalytic activities of the resulting catalysts were investigated by the degradation of p-chlorophenol under artificial visible light irradiation. The results showed that the lignin-templated TiO2 with a suitable amount of I-doping (I/TiO2-T) had higher catalytic activity than the catalyst prepared form I-doped TiO2 without lignin template (I/TiO2). Complete degradation of p-chlorophenol was achieved by I/TiO2-T with suitable amount of I-doping at 60 min. However, 95.7, 10.7, and 5.5% of the p-chlorophenol was degraded with I/TiO2, TiO2-T, and P25 catalysts, respectively, under 140 min visible light irradiation. The enhanced catalytic activities of the samples with template and I-doping may be due to the small grain size and high specific surface area of the catalysts. The band gap and the electrical properties of TiO2 also could be adjusted with I-doping. The I-doped TiO2 with the extrinsic I5+-to-Ti4+ and the iodine-to-oxygen donor defects could be excited by visible irradiation for efficient pollutants degradation. A possible photocatalytic mechanism for the degradation of the pollutants with I/TiO2-T under visible light irradiation was also proposed.
关键词： Mesoporous TiO2,Visible light,I-doped,Lignin template
更新于2025-11-14 17:03:37
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Improved H2-generation performance of Pt/CdS photocatalyst by a dual-function TiO2 mediator for effective electron transfer and hole blocking
摘要： Surface modification with noble metal cocatalysts was proved to be a useful route for boosting photocatalytic efficiency of various photocatalysts. Nevertheless, considering the random dispersion of metallic cocatalysts on the photocatalyst surface, the noble metal-loaded photocatalyst generally shows a limited enhancement of its activity because the noble metals can also work as the recombination sites of photoinduced charges. In this paper, TiO2 as a dual-function mediator (for effective electron transport and hole block) is successfully introduced into the interface of Pt and CdS to form Pt-TiO2/CdS photocatalyst, with an aim of suppressing the high recombination rate of electron-hole pairs on the Pt active sites. Under visible light, all the prepared Pt-TiO2/CdS displayed distinctly enhanced photocatalytic hydrogen-generation performance and the Pt-TiO2/CdS(8%) attains the highest photocatalytic H2-production rate (294.2 μmol/h), a value significantly higher than that of Pt/CdS about 3.2 time. A dual-function TiO2-mediated mechanism was put forward to account for the superior hydrogen production of Pt-TiO2/CdS photocatalyst, namely, the TiO2 layer in the Pt-TiO2/CdS not only works as electron-transport layers to effectively transfer photogenerated electrons to promote the H2-production reaction on Pt cocatalysts, but also acts as hole-block layer to prevent the possible recombination of photogenerated charges on the Pt active sites, resulting in a distinct improvement of final H2-generation activity.
关键词： Photocatalysis,Pt,H2 generation,CdS,TiO2
更新于2025-11-14 15:27:09
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Structural and photocatalytic properties of co-doped hybrid ZrO2–TiO2 photocatalysts
摘要： In this study, pure TiO2, ZrO2, and hybrid ZrO2–TiO2 photocatalysts were synthesized through solgel process and calcined at three different temperatures. The synthesized photocatalysts were characterized using powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FESEM), Brunauer–Emmet–Teller (BET), ultraviolet–visible (UV–Vis) spectrometer, and photoluminescence (PL) spectrometer. The PXRD patterns show that the rutile phase of TiO2 was suppressed through co-doping with ZrO2 and produced small crystallite size. The hybrid photocatalysts with small crystallite size recorded the highest surface area of 114.7 m2/g compared to pure TiO2 and ZrO2 photocatalysts as confirmed by BET analysis. Irregular size and shape was observed in the hybrid photocatalysts compared to spherical shape and size in TiO2 and flaky shape in ZrO2 as shown by the FESEM images. The optical properties of the photocatalysts investigated using UV–Vis spectroscopy showed a decrease in band gap energy of pure TiO2 through linear extrapolation from the Tauc’s plot despite the slightly higher band gap energy of the hybrid photocatalysts. However, PL analysis showed that doping of ZrO2 into TiO2 increased the separation efficiency of the electron–hole pairs and enhanced the photocatalytic activity. The phenol degradation of the hybrid ZrO2–TiO2 photocatalysts was higher compared to those of the pure TiO2 and ZrO2.
关键词： Hybrid TiO2–ZrO2 photocatalysts,Solgel,Phenol degradation
更新于2025-11-14 15:25:21