Search

Well-aligned CeO 2 /TiO 2 nanotube arrays photocatalyst was successfully prepared by anodization and microwave homogeneous synthesis technique. The nanocomposites were characterized by X-ray diffraction(XRD), Raman spectroscopy(RS), scanning electron microscopy(SEM), energy-dispersive spectrometry(EDS), transmission electron microscopy(TEM), UV–vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), photocurrent-time measurements, and electrochemical impedance spectroscopy(EIS). The TiO 2 nanotube arrays showed enhanced optical properties with significant red shift after the introduction of CeO 2 nanoparticles. Photocatalytic activities of the prepared samples were examined by the photocatalytic oxidation of benzothiphene (BT) under visible light irradiation. The CeO 2 /TiO 2 nanotube arrays photocatalyst showed higher photocatalytic activity than that of TiO 2 nanotube arrays. It was found that more than 90% of sulfur compounds in model oil were photocatalytic oxidized and removed by using CeO 2 /TiO 2 nanotube arrays as photocatalyst. [ABSTRACT FROM AUTHOR]

The construction of well-defined heterojunction structure is considered to be an effective way to improve the efficiency of photocatalytic hydrogen evolution. One-dimensional(1D) Y-doped CeO 2 nanorods/two-dimensional (2D) ZnIn 2 S 4 S-scheme heterojunction composite was prepared via hydrothermal and solvothermal method. When the mass ratio of Y-doped CeO 2 to ZnIn 2 S 4 is 10 %, the composite exhibits the highest hydrogen evolution rate of 857 μmol·g−1·h−1 under visible light irradiation, which is obviously better than pure Y-doped CeO 2 and ZnIn 2 S 4 respectively. Meanwhile, transient photocurrent spectra, photoluminescence (PL) spectra and electrochemical impedance spectroscopy（EIS）measurement indicate that the separation efficiency of photogenerated electrons and holes in the composites is higher. Finally, the S-scheme heterojunction mechanism is determined through UV–vis diffuse reflectance spectra (DRS), VB-XPS spectrum, electron spin resonance (ESR) spectra, ultraviolet photoelectron spectroscopy (UPS) spectra and energy band structure analysis. This study may provide an effective S-scheme heterojunction photocatalysts for photocatalytic hydrogen evolution applications. • 1D/2D Y-doped CeO 2 /ZnIn 2 S 4 heterojunction was synthesized successfully. • Well-defined heterojunction structure is conducive to charge-carriers transfer. • The composite has excellent photocatalytic H 2 evolution activity and recyclability. • S-scheme photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

Abstract: We have developed a one-pot chemical approach to prepare palygorskite (PG) supported mesocrystalline Ce1− x Mn x O2 oxides with controllable surface coverage, crystal orientation and dopant fraction. Transmission electron microscopy reveals that the surface is composed of a single phase based on the face-centered cubic CeO2 and the crystals are highly oriented with the axis [100] parallel to the longitudinal direction of PG as if the Mn3+ molar fraction x is 0.2 or less. However, when the Mn3+ molar fraction is larger than 0.2, a mixture of face-centered cubic (fcc) CeO2 and body-centered cubic (bcc) α-Mn2O3 forms and the preferential crystal orientation disappears as revealed by XRD and Raman measurements. The acetate group and PG support are believed to play significant role in the mesoscally oriented attachment. The effects of the molar fraction of Mn3+ on the degradation rate of methyl orange are investigated. Results show that PG/Ce1− x Mn x O2 composite has remarkably enhanced catalytic activity as compared with pure PG and PG/CeO2, and the maximum degradation rate of methyl orange reaches 98% when the molar fraction x is 0.2, due to the unique mesocrystalline structure with adequate oxygen vacancies as well as predominant exposure of highly active {200} planes. [Copyright &y& Elsevier]

Abstract: Ce1− x La x O2− δ nanoparticles supported on the attapulgite nanocomposites were prepared by using hydrothermal synthesis method. The nanocomposites were characterized by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersive spectrometry (EDS), scanning electron microscope (SEM), and nitrogen adsorption–desorption. The results showed that the Ce1− x La x O2− δ nanoparticles were attached to the surface of the attapulgite. The ATP/Ce1− x La x O2− δ nanocomposites displayed the excellent catalytic activity for decomposing methylene blue. When La addition reaches x =0.2, the decolorization ratio of methylene blue using ATP/Ce0.8La0.2O1.9 as catalyst reached over 99%. [Copyright &y& Elsevier]

Abstract: Prism-like mesocrystal CeO2 were synthesized via a hydrothermal method. TG–DSC, powder X-ray diffraction (PXRD), TEM, selected electron diffraction (SAED), and HRTEM were employed to characterize the samples. The results showed that the products had prism-like morphology and owned mesocrystal structure. The effect of the molar ratios of HMT to Ce(NO3)3·6H2O was investigated. A possible formation mechanism was put forward that the nanocrystals aggregated along with the epitaxial orientation following the manner of coherent interface. The UV–vis adsorption spectrum exhibited the red-shift phenomenon compared with bulk CeO2 presumably due to the existence of considerable defects in particular twin boundaries in this unique structure. [Copyright &y& Elsevier]

The novel nitrogen doped two-dimensional CeO 2 –TiO 2 nanosheets with a thickness of less than 5 nm were synthesized by a facile impregnation method using Chinese rose petals as biological templates. The detailed characterization by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) exhibited that the CeO 2 –TiO 2 composites exactly duplicated the microstructure of Chinese rose petal and the self-owned nitrogen was successfully doped into the CeO 2 –TiO 2 composites, which could enhance the visible light absorption efficiency. UV–Vis diffuse reflection spectroscopy (DRS), photocurrent measurement (PM), electrochemical impedance spectroscopy(EIS) and photoluminescence spectroscopy (PL) were used to analyze the electrons and holes separation efficiency, which revealed that CeO 2 and TiO 2 formed well-defined hetero junctions promoting the effective separation of photogenerated electrons and holes. The photocatalytic activity of the samples was evaluated by photocatalytic degradation of dibenzothiophene (DBT) in model oil. The amount of hydrogenperoxide (H 2 O 2) and photocatalysts, the molar ratios of Ce and Ti in CeO 2 –TiO 2 composites as photocatalytic reaction conditions were investigated. Results showed that the removal rate of DBT could reach 93.7% under visible light irritation for 3 h, when the molar ratio of Ce/Ti was 1/1, the mass ratio of photocatalyst/DBT was 1/2 and the molar ratio of H 2 O 2 /DBT was 2/1. The trapping experiments confirmed that the photoinduced active species (•OH radical) was responsible for the degradation of DBT. Further studies demonstrated that DBT was converted to the corresponding sulfone, which could be extracted by the polar solvent. Moreover, a plausible mechanism for the photocatalytic oxidative desulfurization of this nanocomposite was proposed. Image 1 • CeO 2 –TiO 2 nanosheets were fabricated using Chinese rose petals as biological templates. • Nitrogen doping enhanced the visible light absorption of photocatalysts. • CeO 2 /TiO 2 heterostructure facilitated the separation of photogenerated electron-hole pairs. • The CeO 2 –TiO 2 nanosheets exhibited excellent photocatalytic desulfurization activity. • Hydroxyl radicals are mainly responsible for the photocatalytic oxidation. [ABSTRACT FROM AUTHOR]

A novel Bi 2 W 1−x Mo x O 6 /Montmorillonite (MMT) nanocomposite was prepared by one-pot hydrothermal method. XRD, TEM, Raman, UV–vis, FT-IR, PL and XPS were employed to characterize the nanocomposites. The photocatalytic desulfurization properties of Bi 2 W 1−x Mo x O 6 /MMT nanocomposites were performed by oxidizing dibenzothiophene (DBT) in the model oil under visible light irradiation. Results indicate that the molar fraction of Mo doping has critical impact on the desulfurization rate. Adequate Mo doping may form well-defined “solid solution/co-precipitation” heterostructure of Bi 2 W 1−x Mo x O 6 /Bi 2 MoO 6 , which enhances the visible light absorption efficiency and promotes the separation rate of photogenerated electron-hole pairs, thus leads to the improved photocatalytic desulfurization performance. The desulfurization rate of the model oil can reach 95% when the molar fraction x is 0.7 under visible light irradiation for 3 h. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA), a prevalent organic pollutant found in wastewater environment, is notorious for its resistance to natural degradation, raising significant ecological and human health concerns. In this study, a "signal-on" photoelectrochemical aptasensing system was designed for detecting BPA in real water samples with high specificity and sensitivity. One-dimensional (1D) β-FeOOH nanobelts were synthesized on a two-dimensional (2D) porous carbon nitride (g-C 3 N 4) through an in-situ growth procedure. The β-FeOOH/g-C 3 N 4 nanocomposites demonstrated superior photoelectric conversion efficiency due to several factors: (i) The 1D nanobelt-like structure of β-FeOOH shortens the charge transfer path within the nanocomposite, enabling directional and rapid migration of photoinduced charges from the interior to the surface. (ii) β-FeOOH possesses strong visible absorption capabilities, enhancing the utilization of g-C 3 N 4 under photoexcitation, resulting in the generation of numerous photo-induced carriers. (iii) The in-situ formation of the β-FeOOH/g-C 3 N 4 heterojunction establishes an intimate interfacial contact, facilitating the rapid separation and transfer of charges between β-FeOOH and g-C 3 N 4. A photoelectrochemical aptasensing platform based on the photoactive material of β-FeOOH/g-C 3 N 4 detects BPA with reduced photocurrent owing to the presence of BPA-aptamer macromolecules on the electrode surface. This BPA detection system exhibits excellent linearity over a wide concentration range from 10 pM to 10 nM, with high sensitivity (a detection limit of 3.5 pM), stability, specificity, and repeatability. Furthermore, this research offers a straightforward and rapid sensing platform for monitoring BPA enriched water environments. • 1D-FeOOH nanobelts on 2D g-C 3 N 4 was designed to detect trace Bisphenol A. • The efficiency of photoelectric conversion was enhanced by the unique structure. • The BPA detection system exhibits excellent linearity and high sensitivity. [ABSTRACT FROM AUTHOR]

Photocatalytic N 2 fixation coupled with biomass conversion into value-added chemicals is an attractive strategy for achieving sustainable and ecological development. Herein, the octahedral cation sites of acid-activated palygorskite (Pal) were substituted by Fe ions using microwave hydrothermal method to achieve lattice reconstruction. Then FeIn 2 S 4 /Fe-Pal (FIS/Fe-Pal) composites were synthesized by loading indium iron sulfide on the surface of Fe-Pal, which were employed for photocatalytic nitrogen fixation coupling with cellulose biomass conversion. When the mass ratio of Fe-Pal to FeIn 2 S 4 was 0.4:1, the photocatalyst showed the highest NH 4 + production of 583 μmol/g and formate production of 265 μmol/g after 6 h illumination. The sulfur vacancies together with Fe ions in FIS/Fe-Pal formed dual active sites favoring the adsorption and activation of N 2 in glucose solution. In addition, the introduction of FeIn 2 S 4 expanded the light absorption range improving the light utilization. This work opens up a new window for the coupling of nitrogen fixation and biomass conversion by taking advantage of natural clay and solar energy. ● Fe modified Pal form S-scheme heterojunction with FeIn 2 S 4. ● Sulfur vacancies and Fe ions promoted the adsorption and activation of N 2. ● FeIn 2 S 4 expanded the absorption range of light. ● Photocatalytic nitrogen fixation coupled with biomass conversion was both enhanced. [ABSTRACT FROM AUTHOR]

Manganese oxide and cerium dioxide (Mn 3 O 4 /CeO 2 ) nanorods grown on the surface of graphene nanosheet were successfully obtained by hydrothermal treatment. The supercapacitor performance of Mn 3 O 4 /CeO 2 nanorods nanostructured electrodes was greatly improved. The composite shows the excellent specific capacitance as high as 209.2 F g −1 in 1 M Na 2 SO 4 electrolyte and the good long term cycle stability. The prominent electrochemical properties could be attributed to the enhanced conductivities and the improved accessible area for ions in electrolytes. The present study provides a facile way to design a high-performance Mn 3 O 4 /CeO 2 -graphene based supercapacitor electrode and the conception is extendable to other pseudocapacitive electrodes. [ABSTRACT FROM AUTHOR]

Using clean and renewable solar energy to convert nitrogen to ammonia is promising, however the low utilization of light and the high cost of catalyst restrain its application. Herein, novel two-dimensional(2D) silicate CaCuSi 4 O 10 nanosheet was prepared by high-temperature solid state method using silica derived from palygorskite clay (Pal) and calcium carbonate derived from egg shells, respectively. The photocatalytic nitrogen fixation was performed using CaCuSi 4 O 10 compound as catalyst. The effect of flux content on the ammonia generation rate was investigated. Results demonstrated that the 2D CaCuSi 4 O 10 nanosheet can chemically adsorb and activate N 2 due to the high surface area along with abundant oxygen vacancies. The ammonia evolution rate of CaCuSi 4 O 10 can reach up to 60.3 μmol·g−1·h−1 and 15.6 μmol·g−1·h−1 under simulated solar light and near infrared (NIR) light irradiation, respectively. The enhanced photocatalytic nitrogen fixation can be ascribed to the up-conversion capability of CaCuSi 4 O 10 , which converts NIR into visible and UV light improving the utilization efficiency of full solar spectrum. Current study may offer a promising strategy for cost-effective photocatalytic nitrogen fixation under full spectrum. • 2D silicate CaCuSi 4 O 10 nanosheet prepared using mineral and biomass. • CaCuSi 4 O 10 compound owned abundant oxygen vacancies favoring N 2 activation. • Up-conversion capability of CaCuSi 4 O 10 improved solar energy utilization. • CaCuSi 4 O 10 nanosheet demonstrated cost-effective photocatalytic nitrogen fixation. [ABSTRACT FROM AUTHOR]