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Plasmonic oxidation of glycerol using AuPd/TiO2 catalysts
摘要： AuPd nanoparticles supported on P25 TiO2 (AuPd/TiO2) were prepared by a facile sol-immobilisation method and investigated for surface plasmon-assisted glycerol oxidation under base-free conditions. The AuPd/TiO2 samples were characterized by UV-vis spectroscopy and transmission electron microscopy. The sol-immobilisation method readily permitted the Au:Pd molar ratio to be changed over a wide range whilst keeping the mean particle size of the AuPd nanoparticles at 3nm. Visible light irradiation during the reaction has a beneficial effect on the conversion of glycerol with the most marked effect being observed with gold-rich catalysts and the increase of conversion on light irradiation increases linearly with the gold content of the nanoparticles. The reaction selectivity is also affected by the plasmon-assisted oxidation and glycolic acid, not observed during the dark reactions, was observed for all illuminated reactions due to the enhanced activity of these catalysts.
关键词： visible light irradiation,AuPd nanoparticles,glycerol oxidation,plasmonic photocatalysis,sol-immobilisation
更新于2025-09-11 14:15:04
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Enhanced activity of β-Ga2O3 by substitution with transition metal for CO2 photoreduction under visible light irradiation
摘要： Gallium oxide semiconductors have been developed as effective photocatalysts for water splitting driven by UV light irradiation, but there is no relevant study for the CO2 photoreduction application. Herein, we report the first investigation of β-Ga2O3 applying to photocatalytic CO2 reduction under visible light irradiation by doping transition metal ions (M = V, Cr, Mn, Fe, Co, Ni and Cu) onto the framework. Using sol-gel method, a series of transition metal ions incorporated β-Ga2O3 have been successfully obtained, in which the transition metal substitution content is 2 mol %. The β-Ga2O3:M photocatalysts are characterized completely by diverse tests (e.g., XRD, XPS, UV-Vis DRS, SEM). The effective replacement of Ga3+ ion by M ions significantly expands the scope of spectral response from UV light to visible light, and Fe3+, Co2+, Ni2+ significantly enhance the photocatalytic activity under visible light irradiation. In these cases, CO and H2 are evolved as the reduction products from CO2 and H+ by the generated electrons, respectively. Among these effective catalysts we prepared, β-Ga2O3:Ni exhibits the most substantial CO formation rate of 14.3 μmol/h at 30 °C, and the selectivity for CO evolution exceeds 60.9 %. Furthermore, the CO formation rate increases to 24.6 μmol/h after loading of Ag as the co-catalyst. The stability of the Ag/β-Ga2O3:Ni are verified after five cycle of CO2 photoreduction under visible light.
关键词： transition metal substituted,visible light irradiation,CO2 photoreduction,gallium oxide
更新于2025-09-10 09:29:36
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Controllable synthesis of flower-root shaped Bi2O3/Bi2MoO6 heterostructures as an efficient photocatalyst under visible light irradiation
摘要： In this article, Bi2O3/Bi2MoO6 composites were synthesized hydrothermally under optimized conditions, by adjusting pH, the concentration of polyvinylpyrrolidone (PVP (K30)) and reaction time. During the synthesis process, flower-root shaped zero-gap Bi2O3/Bi2MoO6 heterojunctions were successfully synthesized. The adopted samples were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), Diffuse reflectance spectra (DRS), Photoluminescence (PL), and Fourier transform infrared spectroscopy (FT-IR). The photocatalytic activity was measured under visible-light-irradiation (λ > 420 nm) by degrading tetracycline (TC), ciprofloxacin (CPFX) (antibiotics) and rhodamine B (RhB), methylene blue (MB) (dangerous dyes). The degradation results indicated that photocatalyst sample synthesized at pH 9.0, PVP (K30) 0.05 mol/L and 80 min reaction time (Sup-Bi2O3/Bi2MoO6) demonstrated highly efficient performance. The Sup-Bi2O3/Bi2MoO6 showed the highest apparent rate constant (Kapp) that’s 50% more than the samples prepared at ordinary conditions. Photocatalytic degradation order was i.e. RhB> TC> CPFX> MB, which depends on the polarity of the degrading medium.
关键词： Bi2O3/Bi2MoO6,Flower-root shaped,Heterojunction,Visible light irradiation,Photocatalyst
更新于2025-09-10 09:29:36
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Architecture of Biperovskite-Based LaCrO <sub/>3</sub> /PbTiO <sub/>3</sub> p–n Heterojunction with a Strong Interface for Enhanced Charge Anti-recombination Process and Visible Light-Induced Photocatalytic Reactions
摘要： Erection of a resourceful p?n heterojunction is a state-of-the-art tactic to flourish the charge anti-recombination process at the heterojunction interface and boost the photocatalytic activities under visible light irradiation. In the present work, we have engineered a new series of PbTiO3/LaCrO3 (PT/LC) p?n heterojunction through a facile two-step combustion process. The structural, interface, and optical analysis distinctly revealed a strong intact between p-type LaCrO3 and n-type PbTiO3, elucidating their electronic channelization and substantial reduction of electron?hole recombination at the PbTiO3/LaCrO3 interface, which extend the lifetime and population of photogenerated charges in the p?n heterojunction material. The asymmetry photocurrent in the opposite directions and an inverted characteristic V-shape Mott?Schottky plot of the optimal PT/LC (7/3) material demonstrated the construction of a p?n heterojunction. The optimal p?n heterojunction possesses excellent photo-stability, and it revealed the highest photocatalytic activity toward degradation of phenol, that is, 86% and hydrogen generation, that is, 343.57 μmol in 2 h. The enhanced photocatalytic activities of the p?n heterojunction materials in comparison to pristine ones are due to the higher separation charge carriers across the p?n heterojunction interface, which was deeply elucidated by carrying out electrochemical impedance spectroscopy, time-resolved photoluminescence spectroscopy, and photoluminescence analyses. These materials pave a new way to design the interface intact photocatalyst with an ultrafast approach for migration of photoexcited electrons across the p?n heterojunction and enhance the photocatalytic activities.
关键词： p?n heterojunction,PbTiO3/LaCrO3,visible light irradiation,photocatalytic activities,charge anti-recombination
更新于2025-09-10 09:29:36
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Decoration of SrTiO3 nanofibers by BiOI for photocatalytic methyl orange degradation under visible light irradiation
摘要： BiOI decorated electrospun SrTiO3 nanofibers (BE) with a spiky club structure were fabricated using a rapid microwave-assisted solvothermal method. The exposed (102) plane of BiOI preferentially coupled with the electrospun SrTiO3 fibers aiming to achieve charge neutrality. XRD analysis demonstrated that a BE composite coupled with an optimal content of BiOI exhibited few crystal imperfections. The resulting BE samples showed a higher degradation efficiency towards methyl orange dye under visible light irradiation (λ > 400 nm) compared to the individual BiOI and SrTiO3. The BE composite possessed a high degradation rate of 0.015 (kapp, min–1) and a normalized rate constant of 2.46 × 10–3 (kapp/surface area), which was 7.7 and 1120 times higher than those of BiOI and SrTiO3 alone, and a degradation level over 94.6% within 3 h of irradiation under visible light. The high photocatalytic activity could be attributed to the heterostructure formation, p-n junction at the BE interface, high contact between water and dye molecules with the BiOI covered surface, and extended visible light absorption. This work provides an effective approach to produce BE nanofibers for dealing with methyl orange dye and proves that BE composites have the potential to serve as visible-light-driven photocatalysts.
关键词： Visible light irradiation,Photocatalyst,SrTiO3,BiOI,Nanofiber
更新于2025-09-09 09:28:46
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Nanocrystalline ZnO doped lanthanide oxide: An efficient photocatalyst for the degradation of diesel pollutant in seawater under visible light irradiation
摘要： In this study, a ZnO doped Er2O3 photocatalyst is employed to degrade diesel pollutant in seawater under visible light irradiation. The photocatalyst was prepared by a precipitation method and was characterized by SEM and XRD analysis. The experimental results proved that the nanocrystalline photocatalysts were highly active in the visible region. The photocatalytic degradation efficiency of diesel was analysed by various experimental parameters namely dosage, doping ratio, initial concentration of diesel, pH value, concentration of H2O2 and illumination time. The degradation of diesel pollution in seawater was optimized by orthogonal experiment. According to the results, the removal rate of diesel is less than 30 % without any catalysts (only evaporation). The best effect exists when the dose of catalysts was 0.6 g/L, doping ratio of catalysts was 10%, initial concentration of diesel was 0.2 g/L, pH value was 8, concentration of H2O2 was 10 mg/L, illumination time was 1 h. The removal rate of diesel can reach 99.38 %. This study would make ZnO utilize sunlight more efficiently and accelerate the practical application of photocatalytic technology in organic pollutants treatment region.
关键词： visible light irradiation,photocatalyst,Er2O3,diesel pollutant,seawater,ZnO
更新于2025-09-09 09:28:46
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Fast electron transfer and enhanced visible light photocatalytic activity by using poly-o-phenylenediamine modified AgCl/g-C3N4 nanosheets
摘要： Exfoliation of bulk graphitic carbon nitride (g-C3N4) into two-dimensional (2D) nanosheets is one of the effective strategies to improve its photocatalytic properties so that the 2D g-C3N4 nanosheets (CN) have larger specific surface areas and more reaction sites. In addition, poly-o-phenylenediamine (PoPD) can improve the electrical conductivity and photocatalytic activity of semiconductor materials. Here, the novel efficient composite PoPD/AgCl/g-C3N4 nanosheets was first synthesized by a precipitation reaction and the photoinitiated polymerization approach. The obtained photocatalysts have larger specific surface areas and could achieve better visible-light response. However, silver chloride (AgCl) is susceptible to agglomeration and photocorrosion. The PoPD/AgCl/CN composite exhibits an extremely high photocurrent density, which is three times that of CN. Obviously enhanced photocatalytic activities of PoPD/AgCl/g-C3N4 are revealed through the photodegradation of tetracycline. The stability of PoPD/AgCl/CN is demonstrated based on four cycles of experiments that reveal that the degradation rate only decreases slightly. Furthermore, ?O2? and h+ are the main active species, which are confirmed through a trapping experiment and ESR spin-trap technique. Therefore, the prepared PoPD/AgCl/CN can be considered as a stable photocatalyst, in which PoPD is added as a charge carrier and acts a photosensitive protective layer on the surface of the AgCl particles. This provides a new technology for preparing highly stable composite photocatalysts that can effectively deal with environmental issues.
关键词： AgCl,Visible light irradiation,Poly-o-phenylenediamine,g-C3N4 nanosheets,Photocatalytic
更新于2025-09-09 09:28:46
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Photoelectrocatalytic Reduction of Carbon Dioxide to Methanol using CuFe2O4 Modified with Graphene Oxide under Visible Light Irradiation
摘要： Photoelectrocatalytic reduction of CO2 into valuable products can provide energy in a sustainable way with levelling off the concentration of CO2 in our environment. In this study, graphene oxide (GO) incorporated with copper ferrite (CuFe2O4) has been employed to enhance photoelectrocatalytic CO2 reduction under visible light. The TEM and XPS characterization indicated a strong interaction between the CuFe2O4 and GO in the hybrid catalyst. The GO incorporation reduced the e-/h+ recombination in the hybrid catalyst by trapping the photoexcited electrons from CuFe2O4 leading to high methanol yield of 28.8 μmole/Lcm-2 at 20.5% quantum efficiency. The incident photon current efficiency (IPCE) and Faradaic efficiency for methanol formation were observed 8.02% and 87% respectively. The results showed that the photoelectrocatalytic activity for CO2 reduction can be improved by incorporating GO with CuFe2O4 and it provides a universal platform to fabricate GO-CuFe2O4 based hybrid photocatalyst with promising applications in CO2 reduction.
关键词： Visible light irradiation,CuFe2O4,CO2,Graphene oxide,Photoelectrocatalytic reduction,Methanol
更新于2025-09-09 09:28:46
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Visible light enhanced black NiO sensors for ppb-level NO2 detection at room temperature
摘要： Although extensive studies have been carried out on n-type semiconductors for room-temperature gas sensor applications, some intrinsic problems remain. Therefore, other interesting attempts should be adopted to solve these issues, like p-type semiconductors. Previous studies have demonstrated that p-type semiconductor gas sensors exhibit better selectivity and less humidity dependence due to the distinctive oxygen adsorption and surface reactivity. Visible light is used as the external activation source to accelerate the sensing kinetics instead of heating. Stoichiometric NiO cannot absorb visible lights. Inspired by the works of black TiO2, we adopted three methods to prepare black NiO. XPS characterizations reveal that the presence of Ni3+ ions leads to the formation of black NiO. However, not all black NiO samples show good responses to NO2 at room temperature. Three main routes: synthesizing specific morphology with large specific surface area and porosity, introduction of Ni3+ ions and oxygen vacancies, are needed to get the enhanced sensing performance. The black NiO samples with large specific surface area and oxygen vacancies and Ni3+ ions show obvious response towards ppb-level NO2 with visible light irradiation at room temperature. Furthermore, light wavelength is found to play a vital role in the sensing characteristics, and blue light is the optimal choice. Different from traditional NiO sensors operated at high temperatures exhibiting superior response to reducing gases, the black NiO show excellent selectivity towards oxidizing gas, ppb-level NO2, at room temperature illuminated by blue light. In contrast with n-type semiconductors, the black NiO samples also exhibit less humidity dependence.
关键词： Room temperature,NO2 sensor,NiO,Visible light irradiation
更新于2025-09-09 09:28:46
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Synthesis of Al-MCM-41@Ag/TiO <sub/>2</sub> Nanocomposite and Its Photocatalytic Activity for Degradation of Dibenzothiophene
摘要： Mesoporous Al-MCM-41@Ag/TiO2 nanocomposites were synthesized successfully by combining the sol-gel method and hydrothermal treatment, using titanium isopropoxide (TTIP), AgNO3, and Vietnamese bentonite as precursors of Ti, Ag, and Si, respectively. The synthesized materials were well characterized by X-ray powder di?raction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption-desorption isotherm measurements, energy dispersive X-ray spectroscopy (EDX), UV-visible di?use re?ectance spectroscopy (UV-Vis/DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity was evaluated by the photodegradation of dibenzothiophene (DBT) under both UV and visible light irradiation. MCM-41@Ag/TiO2 catalyst exhibited high catalytic activity for the oxidative desulfurization (ODS) of DBT reaching almost 100% conversions at 50°C after 2 h under UV and visible light irradiations. The signi?cant enhanced degradation of DBT over Al-MCM-41@Ag/TiO2 might be due to the synergy e?ects of high surface area of MCM-41, well-distributed TiO2 anatase, and reduced electron-hole recombination rates due to the dispersion of Ag nanoparticles.
关键词： photocatalytic activity,Al-MCM-41@Ag/TiO2,dibenzothiophene,visible light irradiation,oxidative desulfurization
更新于2025-09-04 15:30:14