Assisted Hydrothermal Method Research Articles

Enhanced photocatalytic performance of CuO nanoparticles synthesized via surfactant assisted hydrothermal method

Enhanced photocatalytic performance of CuO nanoparticles synthesized via surfactant assisted hydrothermal method

Selective discrimination and accurate quantification of five target vapors among multiple vapors using 2D CuO and Co3O4 sensors

Selective and sensitive detection of volatile organic compounds (VOCs) are critically needed for various applications like environmental sustainability, industrial safety, healthcare, etc Metal oxides are one of the most explored chemiresistive sensing materials because of their high sensitivity, but they lack selectivity. This work reports synthesis of two metal oxides - CuO and Co3O4 using surfactant assisted hydrothermal method. The 2D morphologies of both the metal oxides were ensured through fielded emission scanning electron microscope. The polycrystalline nature of the materials was studied using X-ray diffractometer and bandgaps were found to be 1.72 eV (CuO) and 1.9 and 2.89 eV (Co3O4) through the Kubelka Munk plot. The two metal oxides were employed to detect four different concentrations (6–50 ppm) of five targeted VOCs (lung cancer biomarkers) - acetone, acetonitrile, isopropanol, methanol, and toluene. In addition, response of the sensors for 6–50 ppm of ethyl acetate, hexanal, ammonia, and NO2 were also recorded as these VOCs are naturally produced in the body as a result of metabolic processes. The responses were recorded for 10 min for all the gases with CuO and Co3O4. Despite the intrinsic metal oxides lacking selectivity towards a specific VOC, careful feature selection achieved a classification accuracy of 95% using random forest (RF) algorithm. Subsequent application of RF model on validation dataset yielded a 91% accuracy in identifying target VOCs. Multilinear regression (MLR) algorithm was then employed to quantify the concentrations of the VOCs and low mean absolute error (MAE) values were obtained.

Hydrothermal synthesis of Step-scheme layer g-C3N4/columnar ZnZrO3 heterojunction photocatalyst toward efficient norfloxacin degradation under solar light

Based on the current sewage dilemma caused by the abuse of broad-spectrum antibiotics, how to remove these antibiotic pollutants (such as Norfloxacin) reasonably and effectively in natural waters is urgent. Herein, a novel Step-scheme g–C3N4–ZnZrO3 (S-scheme, CN-ZZO) heterojunction photocatalysts were synthesized by ultrasonic assisted hydrothermal method, and g-C3N4 (CN) as a self-sacrificing material provides the anchoring platform for ZnZrO3 (ZZO). All the samples were tested toward photocatalytic activity of Norfloxacin (Nor) degradation, and g–C3N4–30%ZnZrO3 (CN-30ZZO) was identified as the finest catalyst to effectively degrade 96 % norfloxacin after 180 min of solar light exposure and stably operate at pH = 7.0 within 5 consecutive runs. Finally, by compared the difference of charge transfer paths and synergistic effect between the heterojunction interfaces of CN and ZZO in the type-ii scheme mechanism and S-scheme, and verified the quenching experiment results (h+-dominated role), it is deduced that CN-ZZO heterojunction belongs to the S-scheme mechanism with stronger photo-redox performance, longer carriers’ lifetime, and more feasible migration pattern.

Synthesis of S-scheme 0D/2D Co2ZrO5/g-C3N4 heterojunction photocatalyst with enhanced visible-light photocatalytic activity for tetracycline

The step-like scheme (S-scheme) heterojunction photocatalyst, which possess an improved electric field, intimate interfacial contact and reasonable energy band structure, is one of the most optimal ways to solve the wastewater problem caused by residual antibiotics. Herein, a new type of S-scheme 0D/2D Co2ZrO5/g-C3N4 (CZO/CN) heterojunction photocatalyst was prepared via an ultrasonic assisted hydrothermal method and used as photocatalyst to degrade tetracycline (TC, 20 mg/L, 100 mL). Compared to pure CN and CZO, the CZO/CN with the optimal design proportion (30CZO/CN) demonstrates the outstanding photocatalytic efficiency for TC degradation under visible-light irradiation, with the degradation rate being 94.8 % within 180 min at pH 5.0. Moreover, the 30CZO/CN exhibits superior stability, which still eliminated 90 % of TC after five times cycle runs. Furthermore, the S-scheme mechanism of photocatalytic TC removal by CZO/CN is proposed by XRD, FT-IR, XPS, UV–Vis DRS and PL analysis, which summarized that the enhanced photocatalytic activity of CZO/CN was mainly ascribed to its larger specific surface area, available light absorption region and appropriate bandgap width, dominated by the S-scheme pattern. This study presents a novel S-scheme g-C3N4-base heterojunction photocatalyst can effectively treat wastewater and provides design ideas for other heterojunctions.

Effect of Synthesis Conditions on CuO-NiO Nanocomposites Synthesized via Saponin-Green/Microwave Assisted-Hydrothermal Method

This work presents the synthesis of CuO-NiO nanocomposites under different synthesis conditions. Nanocomposites were synthesized by merging a green synthesis process with a microwave-assisted hydrothermal method. The synthesis conditions were as follows: concentration of the metal precursors (0.05, 0.1, and 0.2 M), pH (9, 10, and 11), synthesis temperature (150 °C, 200 °C, and 250 °C), microwave treatment time (15, 30, and 45 min), and extract concentration (20 and 40 mL of 1 g saponin/10 mL water, and 30 mL of 2 g saponin/10 mL water). The phases and crystallite sizes of the calcined nanocomposites were characterized using XRD and band gap via UV-Vis spectroscopy, and their morphologies were investigated using SEM and TEM. The XRD results confirmed the formation of a face-centered cubic phase for nickel oxide, while copper oxide has a monoclinic phase. The calculated crystallite size was in the range of 29–39 nm. The direct band gaps of the samples prepared in this work were in the range of 2.39–3.17 eV.

Monitoring of UV-A radiation by TiO2/CdS nanohybrid along with the high on-off ratio

Exposure to UV-A light can have detrimental effects on human health, leading to skin damage and an increased risk of skin cancer. In this study, we employed a hydrothermal-assisted method to cultivate TiO2-decorated CdS nanorods for use in UV photodetectors. Our research culminated in the fabrication of an exceptionally responsive and rapid photodetector based on the TiO2/CdS nanohybrid. X-ray diffraction analysis revealed the hexagonal phase of CdS nanorods, predominantly oriented along the (002) plane, and the presence of the anatase phase of TiO2. Scanning electron microscopy (SEM) measurements confirmed the nanorod structure of TiO2/CdS. Optical properties of the TiO2/CdS nanohybrid were investigated through UV–visible absorbance analysis. Additionally, X-ray photoelectron spectroscopy (XPS) provided insights into the surface composition of the prepared nanohybrid, with peaks corresponding to Cd 3d3/2 and Cd 3d5/2 at binding energies of 411.47 eV and 404.73 eV, respectively, and confirming the presence of titanium through peaks of Ti 2p3/2 and 2p1/2 at binding energies of 458.31 eV and 463.8 eV, respectively. Raman analysis indicated the presence of the anatase phase of TiO2 in the composite. Our device exhibited an impressive detectivity of 9.9 × 1012 Jones, an EQE (external quantum efficiency) of 971.36%, and a high photoresponsivity of 2.86 A/W. These results suggest that TiO2/CdS nanohybrids, prepared using a cost-effective and straightforward method, hold promise for UV photodetection applications.

Cationic and anionic cross-assisted synergistic photocatalytic removal of binary organic dye mixture using Ni-doped perovskite oxide

Organic dyes present in industrial wastewater are the major contributor to water pollution, which harm human health and the environment. Photocatalytic dye degradation is an effective strategy for water remediation by converting these organic dyes waste into non-harmful by-products. Therefore, in this study, Ni-doped LaFeO3 (NLFO) perovskite nanoparticles were extensively explored for photocatalytic degradation of cationic and anionic dyes and their mixture. The NLFO nanoparticles were successfully synthesized by surfactant assisted hydrothermal method under controlled Ni doping. The X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) revealed the variation in size (40–70 nm) of orthorhombic crystalline LFO nanoparticles with Ni doping and hence the size of microspheres (0.78. to 1.78 μm). The kinetic studies revealed that the LaFe0·6Ni0·4O3 performed well by providing degradation efficiency of 99.2% in 210 min, 99.1% in 100 min, and 98.4% in 70 min for Crystal Violet (CV), Congo Red (CR), and their mixture with rate constant of 0.019, 0.039, and 0.055 min−1 respectively. The radical scavenger tests indicated the synergetic contributions of O2− and •OH− active radicals in faster degradation of CV and CR dye mixture. The stepwise fragmentation of dye molecule during the photocatalytic degradation identified from the LCMS indicates the degradation of CV dye through de-alkylation and benzene ring breaking, whereas azo bond cleavage and oxidation lead to low molecular weight intermediates for CR dye, which all together helped to degrade their dye mixture (50 mg L−1 and 100 mg L−1) in significantly lesser time (70 min). Overall, the Ni-doped LFO microsphere consisting of nanoparticles acts as a superior catalyst for the more efficient and faster degradation of binary dye mixture.

Synthesis of Pt/FeVO4: A novel heterostructure for efficient photocatalysis

In this work, a unique platinum-loaded iron vanadate (Pt/FeVO4) composite for escalating the photocatalytic performance via the facile sonicated assisted hydrothermal method was synthesized. Morphological results revealed that the FeVO4 and well-dispersed Pt/FeVO4 particle is in the range of 150–200 nm size, which developed transportation of the photogenerated electrons into FeVO4, resulting in efficient separation of the photogenerated carriers in coupled Pt/FeVO4 nanocomposite heterostructure. The multi-characterizations results indicate an excellent adsorption ability and enhanced surface plasmon resonance (SPR) of Pt/FeVO4 composites as these composites are strongly associated with Pt loading. The induced impedance spectroscopy and photoluminance results demonstrated that Pt enhances separation efficiency as well as transferring rates for photogenerated charges. The ESR data suggests that the reactive oxygen species (OH•) was the most reactive specie agent with h+, •O2¯ having a minor role in methylene blue (MB) degradation.

Novel synthesis strategy of SAPO-11 molecular sieve with superior performance for hydroisomerization of long-chain n-alkanes: Supergravity-cyclone assisted hydrothermal crystallization method

In this work, we successfully synthesized high performance SAPO-11 molecular sieve via the novel supergravity-cyclone assisted hydrothermal crystallization method for the first time. The initial gel was subjected to cyclone treatment and supergravity shearing treatment to obtain the secondary molecular sieve precursor mixture with high viscosity and micro-bubble distribution. The effects of supergravity shear-cyclone operation on the physicochemical properties of SAPO-11 molecular sieve were investigated. The supergravity-cyclone treatment improved the textural properties and acidity of SAPO-11 molecular sieve. The effects of support properties on the properties of active phase of NiWS-support catalyst and its catalytic performance for hydroisomerization of n-hexadecane were further investigated. NiW/SAPO-11-B showed more active phase with hydroisomerization kinetics advantage and nearly doubled yield of i-hexadecane compared with conventional SAPO-11-based catalyst. The process and mechanism of synthesizing high performance SAPO-11 molecular sieve via the supergravity-cyclone technology were explored. It was found that the supergravity-cyclone assisted crystallization method shortened the crystallization time of SAPO-11 and improved the crystallization efficiency. In addition, the hydroisomerization kinetics of n-hexadecane on SAPO-11-based NiWS supported catalyst was studied. The structure–activity relationship between the structure of active phase and the formation of CUS was investigated, and the influence of support properties on the properties of NiWS active phase and their synergistic mechanism in the hydroisomerization of n-hexadecane were revealed. This is expected to provide a new strategy for the synthesis of high performance SAPO-11 molecular sieve and the preparation of non-noble metal supported catalyst with superior hydroisomerization performance for long-chain alkanes.

Synergistic visible light assisted photocatalytic degradation of p-chlorophenol and rifampicin from aqueous solution using a novel g-C3N4 quantum dots incorporated α-MoO3 nanohybrid – Mechanism, pathway and toxicity studies

In this work, a simple g-C3N4 quantum dots enriched MoO3 nanohybrid was formulated for the synergistic photocatalytic degradation of an industrially active organic pollutant, p-chlorophenol (PCP) and a widely prescribed antibiotic, rifampicin (RIF). The nanohybrid was synthesised via a facile ultrasonic assisted hydrothermal method and characterized using various characterization analysis. The efficient Z-scheme charge transfer of the nanohybrid resulted in the elimination of 98% PCP and 89% RIF under visible light with a rate constant of 0.012 and 0.006 min−1 respectively. The photocatalysis was attributed to the formation of both hydroxyl (OH•) and superoxide (O2•-) radicals in the resulting nanohybrid. The intermediates formed in the course of reaction were estimated through gas chromatography-mass spectroscopy/mass spectroscopy (GC-MS/MS) analysis and a suitable degradation pathway was constructed. The structural stability and reusability of the nanohybrid was affirmed through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis to outweigh the industrial potential of the catalyst, with 85% PCP and 80% RIF removal efficiency after six cycles of degradation. In addition, the mineralization of the pollutants was confirmed by total organic carbon analysis. Further, the toxicity of the drug and the formed intermediates was determined using ecological structure activity relationships (ECOSAR) software. On the whole, this work provides an excellent insight for the development of environment-friendly materials in a large scale for the degradation of water-based pollutants.

Rapid synthesis of AgInS2 quantum dots by microwave assisted-hydrothermal method and its application in white light emitting diodes

Rapid synthesis of AgInS2 quantum dots (AIS QDs) with high quantum yield and crystallinity in aqueous phase has been identified as a research priority in the realm of colloidal semiconductors. Herein, microwave assisted-hydrothermal method was used to react for 5 min at 120 °C to prepare AIS QDs with high luminescence properties. Meanwhile, 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4) ionic liquid (IL) was employed as a wave absorber to enhance the photoluminescence quantum yield (PLQY) and shorten the reaction time. The AIS QDs exhibited spectral tunability by adjusting the IL/AgIn molar ratio from 0 to 10, and the luminescence peak position could be tuned from 597 nm to 670 nm. The PLQY of AIS QDs reached 27.67% at the IL/AgIn molar ratio of 2.5, and the fluorescence lifetime upped to 360.4 ns. In addition, the ZnS shell was coated on the surface of the QDs with Zn/AgIn= 3 by reacting at 90 °C for 2 min, and the PLQY could reach to 35.66%, which further improved the emission performance of the AIS QDs. Finally, QDs and commercial (Ba, Sr)Si2O2N2:Eu2+ phosphors were mixed to fabricate white light emitting diodes (WLEDs) devices. AIS@ZnS QDs-based WLED showed color rendering index (CRI) of 87.7 and correlated color temperature (CCT) of 5220 K. And its luminous efficiency (LE) reached 80.13 lm/W, which is 2.16 times higher than that of AIS QDs-based WLED (37.1 lm/W), indicating the good application prospect in WLEDs.

Facile synthesis of rod-like α-FeOOH nanoparticles adsorbent and its mechanism of sorption of Pb(II) and indigo carmine in batch operation

• Nanoparticles of α-FeOOH was synthesized and characterized using XRD, FTIR, SEM, TEM and DLS methods. • The Rod-like α-FeOOH Nanoparticles was used for removal of Pb(II) and Indigo carmine from aqueous solution in batch adsorption mode. • The optimum adsorption of Pb(II) occurred at pH 10 in 180 min agitation with initial concentration of 800 mg/L. • The optimum adsorption of indigo carmine occurred at pH 4 in 150 min agitation with initial concentration of 50 mg/L. • The adsorption capacity of α-FeOOH Nanoparticles for Pb(II) was 287.98 mg/g while indigo carmine was 18.99 mg/g. • Pseudo-second order kinetics and intraparticle diffusin models fitted best and the adsorption processes were spontaneous and endothermic in nature. Nanoparticles (NPs) of α-FeOOH were synthesized by hydrothermal assisted method. X-Ray Diffraction (XRD) result showed that single-crystalline orthorhombic α-FeOOH was formed, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) images showed that the synthesized α-FeOOH nanoparticles were rod-like in shape, while Dynamic Light Scattering (DLS) study gave average nanoparticles sizes of 58.24 nm. The mechanism of batch adsorption of Pb(II) and IDC onto α-FeOOH NPs adsorbent were studied at various conditions of solution pH, concentration, adsorbent dose, temperature and time of agitation. The optimum adsorption capacity of Pb(II) and IDC at pH 10 and 4 were estimated as 287.98 and 18.99 mg/g at 313 and 318 K respectively. The Langmuir isotherm model fitted well with regression coefficient, R 2 = 0.9898 and 0.9966 for Pb(II) and IDC respectively. The pseudo-second-order kinetics best described the sorption processes of Pb(II) and IDC respectively, with R 2 = 0.9974 and 0.9861. However, intraparticle diffusion and pore filling mechanism were found to control the adsorption rates. The change in Gibbs free energy (ΔG°) obtained were negative indicating spontaneous adsorption processes, while positive values of ΔH (+107.08 and +102.15 KJ/mol) and ΔS (+0.361 and +0.341 KJ/mol) for Pb(II) and IDC respectively, showed endothermic and randomness at the NPs of α-FeOOH-aqueous interface during the adsorption processes. The activation energy, E a , were found to be +3.307 and +6.552 KJ/mol for adsorption of Pb(II) and IDC respectively, showing that adsorption onto α-FeOOH NPs adsorbent were physical processes with external diffusion as the rate determining step.

Controlled grain boundary interfaces of reduced graphene oxide in Ag2Se matrix for low lattice thermal conductivity and enhanced power factor for thermoelectric applications

Silver Selenide (Ag2Se), a promising thermoelectric (TE) material due to its high proficient performance in (300–400) K. In this report, Ag2Se and its composites with reduced graphene oxide (rGO) were synthesized by sonochemical assisted hydrothermal method followed by hotpress densification technique. The structural analysis confirmed the orthorhombic phase of Ag2Se and the composition of Ag–Se–Ag with rGO is confirmed from binding energy shift in X-ray photoelectron spectroscopy (XPS) analysis. The phase transition from orthorhombic to cubic phase is identified around (390–450) K from TG-DTA analysis. For 30 wt % of rGO in Ag2Se, the very low thermal conductivity (κ) of ∼0.492 Wm−1K−1 is obtained at 333 K. The maximum zT of ∼0.39 is achieved at 363 K for Ag2Se with 30 wt % rGO. The facile synthesis with modification by rGO shows the untapped potential of very low thermal conductivity in Ag2Se that is yet to be uncovered for TE generators.

Highly ordered pure and indium-incorporated MCM-41 mesoporous adsorbents: synthesis, characterization and evaluation for dye removal

Highly ordered pure MCM-41 and In-MCM-41 mesoporous adsorbents (with Si/In = 95 (IM0.05) and Si/In = 90 (IM0.1)) were synthesized using the hydrothermal-assisted method. The structural, morphological and texture characteristics were investigated by XRD, N2 adsorption–desorption, SEM-EDX, TEM, diffuse reflectance (DR) and FTIR. The broadening XRD diffraction peaks as well as the shifts to higher and lower 2-theta in IM0.05 and IM0.1, respectively, confirmed the incorporation of indium atoms in the MCM-41 structure. SEM-EXD and TEM images showed that pure MCM-41 and IM0.05 preserve a highly long-range well-ordered hexagonal pore structure, on the other hand, high loading of indium (IM0.1) resulted in partially irregular pore-ordering and morphological defects related to a partial dissolution of MCM-41 structure. The infrared spectra of In-incorporated samples showed a decrease in the transmittance intensity of MCM-41 characteristic peaks with little shifts relative to the pure MCM-41 sample. The potential of pure MCM-41 and In-MCM-41 samples for adsorption of dyes was preliminarily investigated. The removal efficiency of both methylene blue and basic yellow-28 (BY28) was enhanced by the incorporation of indium in the MCM-41. The adsorption equilibrium data of BY28 dye on pure, IM0.05 and IM0.1 samples fitted well with Langmuir adsorption model with adsorption capacity of 123.46, 156.99 and 158.48 mg g−1 respectively. The calculated free adsorption energy obtained from D–R isotherm was found to be 26.7 kJ mol−1 referring to that the adsorption of BY28 on IM0.05 adsorbent is chemical. The adsorption kinetic of BY28 on IM0.05 sample followed the pseudo-second-order model. The adsorption experiments revealed that the prepared samples can be used as effective adsorbents for the removal of dyes in aqueous solutions with good recovery and recyclability.Graphical

Rapid Synthesis of Agins2 Quantum Dots by Microwave Assisted-Hydrothermal Method and its Application in White Light Emitting Diodes

Rapid Synthesis of Agins2 Quantum Dots by Microwave Assisted-Hydrothermal Method and its Application in White Light Emitting Diodes

Enhanced degradation of carbamazepine by BiOX (Cl, Br, I) composite photocatalysts under simulated solar light irradiation

To use solar energy effectively, BiOX (Cl, Br, I) nanosheets with reasonable band gap structure were prepared by ultrasonic assisted hydrothermal method. The prepared BiOX (Cl, Br, I) nanosheets removed 90% of CBZ within 5 min, showing rapid degradation kinetic of 0.3858 min−1. The improved photocatalytic activities can be due to the reduced recombination of photoinduced electron-hole pairs, strong visible-light absorption ability, large surface area and pore. Radicals experiments indicated that the BiOX (Cl, Br, I) generated main holes (h+) and minor electrons (e−) to degrade CBZ. These results demonstrated the good feasibility of BiOX (Cl, Br, I) nanosheets in the degradation of CBZ under simulated solar light irradiation.

Novel Down-converting single-phased white light Pr3+ doped BaWO4 Nanophosphors material for DSSC applications

White Nanophosphors based on praseodymium doped barium tungstate matrix (y mol Pr3+: BaWO4 (PBWO) (y = 0.01, 0.03, 0.05, 0.07 mol) were synthesized by ultrasound assisted hydrothermal method in the presence of citric acid and characterized as novel down-conversion materials for dye-sensitized solar cells (DSSCs) applications. The different prepared PBWO Nanophosphors show high crystalline tetragonal phase with nano-cubic morphology. The PBWO photoluminescence spectra give strong emission peaks at 486, 529, 615, 623 and 643 nm are corresponding to the 3P0→3H4, 3P1→3H5, 1D2→3H4, 3P0→3H6 and 3P0→3F2 transitions of Pr3+, respectively. These photoluminescence spectra are assigned to blue, green and red-light regions which cover the whole visible light region. It means that these Nanophosphor materials are promising materials for down-conversion applications. By varying the Pr3+ ion conc., it was found that the optimum conc. of Pr3+ ion was 0.05 mol which gives the highest photoluminescence intensity. The prepared Nanophosphors were applied in DSSCs as a top down-converting layer on the photoactive TiO2 electrode. A high conversion efficiency (η) of 8.08% was achieved by the application of top (PBWO: 0.05 mol Pr3+) down-converting material compared with a 4.17% efficiency of the non-modified DSSC. This enhancement is probably due to the improved UV radiation harvesting via a down-conversion luminescence process.

Enhancing the catalytic activity of MnO2 via structural phase transition for propane combustion: Promotional role of ionic liquid

A series of manganese dioxide have been synthesized by ionic liquid assisted hydrothermal method and used for propane combustion. 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM-BF4] was selected as the structure-directing agent, which could generate extended hydrogen bonds under hydrothermal conditions. These hydrogen bonds could be used for entropy driving of nanostructures self-assembly, thus regulating the growth of crystal. Meanwhile, the existence of [BMIM-BF4] could interact with [MnO6] octahedron in MnO2 through electrostatic and π-π stacking interactions, eventually leading to the transformation from α-MnO2 to β-MnO2 after calcination. A series of characterization results further indicated that with the assistance of ionic liquid, the morphology of the precursor evolved from nanoflowers to nanorods attached with nanofibers, and the specific surface areas and redox properties were also enhanced. When the molar ratio of KMnO4 to ionic liquid reached 8:1, the obtained Mn-1–500 exhibited the highest catalytic activity for propane combustion. The T90 of propane on Mn-1–500 was about 310 °C, which was nearly 110 °C lower than that of Mn-0–500 prepared without the assistance of ionic liquid. These results could offer a novel strategy for the development of high-performance catalysts.

Oxygen vacancies facilitated visible light photoactivity of CdWO4 prepared by ionic liquid assisted hydrothermal method

In this demonstration, CdWO4 with wonderful visible light photoactivity was synthesized by a hydrothermal method with the assistance of 1-ethyl-3-methylimidazolium dihydrogen phosphate ([Emim]H2PO4) ionic liquid (IL). The existence of oxygen vacancies (OVs) was verified by X-ray photoelectron spectroscopy (XPS) and low-temperature electron spin resonance (ESR). Scanning electron microscope (SEM), XPS and X-ray powder diffraction (XRD) results show that [Emim]H2PO4 affects the growth and surface properties of CdWO4. IL-CdWO4 has higher separation efficiency of photogenerated carriers under visible light irradiation than CdWO4, proven by surface photovoltage spectrum (SPS) and electrochemical measurements. Photoactivity of CdWO4 prepared was investigated using Rhodamine B (RhB) and tetracycline (TC) as simulated pollutants, the consequences exhibit that the visible light photoactivity of IL-CdWO4 toward destruction of RhB and TC is more than 3.45 and 6.78-fold of that of CdWO4, respectively. In view of the observations, photocatalytic mechanism of IL-CdWO4 was proposed.

Controllable Synthesis and Enhanced Photoactivity of Two‐Dimensional Bi2WO6 Ultra‐Thin Nanosheets

AbstractTwo‐dimensional Bi2WO6 ultra‐thin nanosheets were controllably synthesized by a cetyltrimethylammonium bromide (CTAB)‐assisted hydrothermal method. The structure, morphology, energy gap, and thickness of the samples were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), (diffuse reflection spectroscopy) DRS, and so on. The photocatalytic activity of the samples was analyzed by the degradation of rhodamine B. The photocatalytic performance of the ultrathin nanosheets was much enhanced nearly 3.5 folds higher than that of Bi2WO6 nanoparticles, which was attributed to the narrow band gap and the open sandwich structure, resulting in the improved light harvesting and the rapid separation and transfer of the photoinduced charge carriers. According to the radical trapping results, the dominant active species involving in the photocatalytic process were determined.