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The development of photocatalysts with a wide spectral response and effective carrier separation capability is essential for the green degradation of tetracycline hydrochloride. In this study, a magnetic recyclable Z-scheme ZnO/ZnFe2O4 heterojunction (ZZF) was successfully constructed via the solid phase method, using MIL-88A(Fe)@Zn as the precursor. An appropriate band gap width and Z-scheme charge transfer mechanism provide ZZF with excellent visible light absorption performance, efficient charge separation, and a strong redox ability. Under visible light irradiation, the degradation efficiency of tetracycline hydrochloride for the optimal sample can reach 86.3% within 75 min in deionized water and 92.9% within 60 min in tap water, exhibiting superior stability and reusability after five cycles. Moreover, the catalyst in the water can be conveniently recovered by magnetic force. After visible light irradiation for 70 min, the temperature of the reaction system increased by 21.9 °C. Its degradation constant (35.53 × 10−3 min−1) increased to 5.1 times that at room temperature (6.95 × 10−3 min−1). Using thermal energy enhances the kinetic driving force of the reactants and facilitates carrier migration, meaning that more charge is available for the production of •O2− and •OH. This study provides a potential candidate for the efficient degradation of tetracycline hydrochloride by combining thermal catalysis with a photocatalytic heterojunction. [ABSTRACT FROM AUTHOR]

Two-dimensional TiO 2 -based nanosheets (TNSs) co-modified by surface-enriched carbon dots (CDs) and Gd 2 O 3 nanoparticles: (Gd-C-TNSs), capable of exhibiting visible-light-driven photo catalysis were synthesized using a two-pot hydrothermal route. The samples had a sheet-like structure, thickness of approximately 3.6 nm, large specific surface area of 240–350 cm 2 /g. The CDs (2–3 nm) and Gd 2 O 3 nanoparticles (1–2 nm) were highly dispersed over the surface of the nanosheets. The co-modification by Gd 2 O 3 nanoparticles and CDs influenced the crystallinity, crystal structure, and surface area of the TNSs, and improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be improved by an appropriate amount of modification. A very high efficiency was obtained using 0.5 at% Gd/Ti and 3.0 g/L of CDs. The visible-light-induced photocatalytic activity is enhanced under the isolated Cr(VI) system, isolated Rhodamin B (RhB) system, and the synergism between RhB degradation and Cr(VI) reduction for the Gd-C-TNSs photocatalysts. Initially, the photocatalytic activity gradually increased with an increase in the amount of CDs, and then decreased after attaining a maximum, in the case where 0.5 at% Gd/Ti and 3.0 g/L of CDs were used. The enhancement in the photocatalytic activity was attributed to the synergetic effect of the Gd 2 O 3 nanoparticles, TNSs, and CDs in the Gd-C-TNSs composites. The effect led to a fast separation and slow recombination of photo-induced electron–hole pairs. An alternate mechanism for enhanced visible-light photocatalytic activity was also considered. [ABSTRACT FROM AUTHOR]

This paper reports a facile one-pot approach for Mn x O y (Mn = Mn 2+ , Mn 3+ ) loaded TiO 2 -based nanosheets (Mn–TNSs) with surface enrichment of Mn x O y nanoparticles via a simple hydrothermal route. The as-synthesized samples showed clearly sheet-like structure, with high specific surface area (200–300 m 2 /g) and small thickness (ca. 4 nm). The small Mn x O y nanoparticles with uniform size (1–2 nm) were highly dispersed on the surface of the TNSs. Loaded Mn x O y not only have influenced the crystal structure and surface area of the TNSs, but also resulted in considerable enhancement of visible-light absorption and red-shift for TNSs. The results of X-ray photoelectron spectroscopy showed that Mn 2+ and Mn 3+ co-exist in Mn–TNSs. The loading of Mn x O y on TNSs resulted in changes in binding energies of Ti and O. The concentration of Ti 3+ increased gradually with the amount of loaded Mn x O y increasing. The photo-reactivity of the samples were evaluated by measuring the formation of photo-induced hydroxyl radical ( OH) using coumarin (COU) as a probe molecule and photocatalytic degradation of Rhodamin B (RhB) and dichromate (Cr(VI)) under visible-light irradiation. It has been found that the Mn–TNSs photocatalysts showed better visible-light photocatalytic activity for aqueous RhB or Cr(VI) solution. The photocatalytic activity gradually increased with the content of Mn x O y increasing initially, and then decreased after attaining a maximum value at an optimal content (2.5 at.%) of Mn x O y in TNSs for degradation of aqueous RhB or Cr(VI) solution, respectively. The cyclic tests that performed five times demonstrated high stability and recyclable usability of the photocatalysts. A possible alternate mechanism for the enhancement of the photocatalytic activity under visible-light irradiation was also proposed. [ABSTRACT FROM AUTHOR]

Highlights: [•] The titanate nanosheets (TNS) were synthesized by a short hydrothermal reaction time. [•] CdS decorated TNS were prepared via ion-exchange and in situ sulfuration process. [•] The composites show enhanced photocatalytic efficiency and stability. [•] Their catalytic activity is higher than that of the CdS/titanate nanotubes. [•] The quick migration of charge carriers in CdS/TNS increased the photoactivity. [Copyright &y& Elsevier]

TiO2-based nanostructures usually possess excellent photochemical properties. However, the relationship between their dimensionality and photocatalytic activity was rarely investigated. In this study, a series of TiO2-based nanostructures in various dimensionalities (such as nanosheets, nanotubes) were obtained by hydrothermal treatment of P25, and the process of structural evolution was also systematically investigated by TEM, BET, Raman, and XRD analysis. Much higher rate constant (3.7 × 10min) for the degradation of rhodamine B was found for nanosheets, comparing with those of three-dimensional P25 nanoparticles (0.59 × 10 min) and one-dimensional nanotubes (0.85 × 10 min). It is found that the hydrothermally prepared TiO2-based nanosheets possess small thickness (ca. 5 nm) and plentiful surface hydroxyl groups, and the reason why TiO2-based nanosheets possess superior photocatalytic activity is also discussed in detail from the microstructure and surface chemical states. In addition, TiO2-based nanosheets exhibit good reusability in the cyclic experiments, implying a potential application for photocatalytic degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Abstract: Cerium doped TiO2-based nanosheets (Ce-TNSs) photocatalysts were prepared by a one-pot hydrothermal method using cerium nitrate as the cerium precursor. The photocatalysts were characterized by high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), Raman spectra, ultraviolet–visible light diffuse reflectance spectra (DRS), X-ray photoemission spectroscopy (XPS) and fluorescence spectra (FL). The results show that Ce3+ and Ce4+ co-exist in Ce-TNS. The doping leads to changes in binding energies of Ti and O. The concentration of Ti3+ increases gradually when the cerium doping amount keep increasing. Appropriate amount of cerium doping can significantly inhibit the recombination of electron–hole pairs, which is proved by the decline in the intensity of the fluorescence spectra. Ce-TNS with doping ratio of 0.5% (molar ratio) possesses the highest photocatalytic activity when degrading Rhodamine B (RhB), which is 5 times and 1.6 times of that of P25 and the undoped TNS, respectively. It is suggested that cerium ions are efficient electron trappers to improve the separation efficiency of electrons and holes. [Copyright &y& Elsevier]

Abstract: Various contents of Ag nanoparticles were successfully introduced into the N-doped TiO2 photocatalysts via a hydrothermal procedure in the silver-ammonia solutions with different Ag concentrations. Effects of Ag loading on the structure and properties of N-doped TiO2 photocatalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, fluorescence spectroscopy (FL), UV–vis spectroscopy, X-ray photoelectron spectroscopy (XPS), and N2 physical adsorption analysis. The relationship between the stability of N dopants in TiO2 lattice and the Ag loading content was investigated for the first time. The results confirm that Ag nanoparticles loading on TiO2 surfaces significantly restrain the escape of the N dopants from the oxide during the hydrothermal process, and the escape rate of N dopants decreased gradually with the increase of Ag loading amount. The dependence of photocatalytic activity on Ag content was also investigated through degradation of rhodamine B (RhB) under visible light irradiation. It was found that the photocatalytic activity increases gradually with increasing Ag content first, and then decreases after exceeding the optimal Ag content. Therefore, the photocatalytic activity of Ag/N co-modified TiO2 photocatalysts can be adjusted by the Ag content. [Copyright &y& Elsevier]

Abstract: In this paper, TiO2 film coated on fiberglass cloth was synthesized by sol–gel method and further sensitized by CdS nanoparticles using a sequential chemical bath deposition technique. Gaseous benzene was adopted as a model pollutant to evaluate the photocatalytic performances of the supported TiO2 films sensitized with variable content of CdS nanoparticles, which obtained by adjusting the concentration of Cd2+ or S2− precursor solution. Along with the increase of the CdS amount, the photocatalytic activity of these samples initially increases and then shows a downward trend. When the concentration of Cd2+ or S2− precursor solution achieved 0.005M, the sample performs the best photocatalytic property and the degradation efficiency reaches 92.8% and 32.7% under UV–vis and visible light irradiation, respectively. The enhancement of the photocatalytic activity could be attributed to the formation of micro-heterojunction. However, a thick CdS sheath covered catalyst surface will form when high concentration of Cd2+ or S2− solution is used. The low photogenerated electron–hole pairs separation efficiency and the photocorrosion process of CdS decrease the photocatalytic activity gradually. [Copyright &y& Elsevier]

Abstract: TiO2-based nanosheet (TNS) was prepared by the alkaline hydrothermal treatment of P25, which was characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD) and nitrogen adsorption–desorption measurement. Its adsorption and regeneration properties for removal of high-chroma crystal violet (CV) were systematically investigated. The prepared TNS has much higher specific surface area of 207m2/g and exhibits much stronger adsorption for CV than the raw material P25. The maximum adsorption capacity of TNS as determined from the Langmuir isotherm is 56.3mg/g. The enhancement of adsorption capacity is ascribed to the increasing of specific surface area and surface hydroxyl groups, which can provide much more adsorption sites and stronger electrostatic attraction. It was further found that H2O2 can produce a synergetic photocatalytic degradation effect with TNS under UV–Vis irradiation, and the regeneration of TNS was effectively achieved by H2O2-assisted photocatalytic degradation process. The good reusability of prepared TNS in the cyclic adsorption–regeneration experiments indicates that it may be useful for dealing with dye wastewater. [Copyright &y& Elsevier]

Vanadium doped TiO 2 -based nanosheets (V-TNSs) with different V/Ti ratios were prepared by a facile one-pot hydrothermal method using vanadium nitrate and P25 as the vanadium precursor and titanium precursor, respectively. The results indicated that as-synthesized photocatalysts exhibited sheet-like structure with large specific surface area (270–340 cm 2 /g) and small thickness (4–5 nm). XPS results revealed that vanadium exists in the form of V 4+ and V 5+ , and the binding energies of Ti O bonds have been changed with the concentration of vanadium. Vanadium doping resulted in considerable enhancement of visible light absorption, red-shift, and the band-gap of photocatalysts reduced from 3.18 eV to 2.91 eV. The density functional theory (DFT) calculations for band structure and total energy also provided a good explanation and further confirmation for the experimental results. It has been found that the photo-activity increased gradually with the concentration of vanadium, and then decreased after attaining a maximum with an optimal content of vanadium at 1.0 at.% for RhB or Cr(VI). The reaction rate K app of 1.0%-V-TNSs are 9.27-fold and 3.26-fold as compared to undoped TNSs under UV–vis and visible light irradiation, respectively. The cyclic tests that performed six times demonstrated high stability and reusability of the photocatalysts. A possible alternate mechanism for the enhancement of the photocatalytic activity under visible-light irradiation was also proposed. [ABSTRACT FROM AUTHOR]

Piezoelectric polarization is a promising approach to promoting the separation and transfer of charge carriers of photocatalysts by modulating energy band structure. A binary piezoelectric integrated piezo-photocatalytic heterojunction o-KNbO 3 /MoS 2 (o-KN/MS) is fabricated through few-layered MoS 2 nanosheets growth on the ferroelectric orthorhombic KNbO 3 (o-KNbO 3). Under simultaneous light irradiation and ultrasonication, the optimal o-KN/MS exhibits a higher piezo-photocatalytic rhodamine B degradation rate (0.16979 min−1) than individual photocatalysis (0.00981 min−1) or individual piezocatalysis (0.09419 min−1). The piezo-photocatalytic degradation rates of RhB (0.16979 min−1), Cr (VI) (0.00877 min−1), and MB (0.01017 min−1) of o-KN/MS are 2.6, 7.9, and 4.2 times as large as that of single piezoelectric hybrid piezo-photocatalyst c-KNbO 3 /MoS 2 , respectively, where c-KNbO 3 in c-KN/MS refers to non-piezoelectric paraelectric cubic KNbO 3 (c-KNbO 3). At the same condition, the current density for o-KN/MS reaches 54.96 μA/cm2, which is 2.9 folds as high as that of c-KN/MS. These results demonstrate that the altering piezoelectric polarization from the binary piezoelectric materials promotes continuous carrier separation within o-KNbO 3 and MoS 2 but also on the heterojunction interface, which provides a strategy for designing integrated piezo-photocatalyst to achieve efficient pollutant degradation and enhance electrochemical performance. [Display omitted] • A bi-piezoelectric o-KNbO 3 /MoS 2 contains few-layered MoS 2 and o-KNbO 3 nanosheets. • The bi-piezoelectric polarization accelerates charge separation and transfer. • The piezo-photocatalysis yields efficient RhB, Cr (VI) and MB degradation. • The charge migration mechanism of bi-piezoelectric synergistic effect is revealed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ni-TNSs with high stability and recyclable usability were prepared by one-pot method. • Ni x O y loading results in the changes in the structure of the TNSs and red shift. • Ni x O y loading leads to obviously increase of the Ti3+ ions content. • Ni x O y loading can effectively trap electrons to enhance the separation of charges. • Ni-TNSs exhibit excellent visible-light photocatalytic activities for organic pollution. Abstract Two-dimensional (2D) TiO 2 -based nanosheets (TNSs) decorated with surface-enriched Ni x O y (Ni = Ni2+, Ni3+) nanoparticles (Ni-TNSs) were synthesized and found to exhibit a high visible light photocatalytic activity. The thickness and high specific surface area of the Ni-TNSs were measured to be ∼5 nm and 280–350 cm2/g, respectively. Properties, such as the crystal structure, crystallinity, surface area and visible light absorption of the TNSs, were closely associated with the distributed nanoparticles of Ni x O y (The particle size is less than 2 nm) on the surface. Surface photocurrent, fluorescence spectroscopy, linear sweep voltammetry and Tafel measurements revealed that the separation efficiency of the photogenerated charge carriers can be improved by optimizing the concentration of Ni x O y (the optimized ratio of Ni/Ti = 3.0 at.%). The photocatalytic degradation of organic pollutants (RhB and MB) under visible light was measured, and the efficiency also strongly depended on the amount of Ni x O y nanoparticles with an optimal percentage of 3.0 at.%. The photoreactivity of the sample was further studied by determining the formation of photoinduced hydroxyl radicals (OH) by applying coumarin (COU) as a probe material and by obtaining ESR spectra of the superoxide radical adducts (O 2 −) trapped by DMPO (5,5-dimethyl-1-pyrroline n-oxide). Ten cyclic tests were used to confirm the high stability. A feasible mechanism is described to interpret the enhanced photocatalysis. [ABSTRACT FROM AUTHOR]

High recombination rate of photogenerated electron-hole pairs and relatively narrow photoresponsive range of TiO 2 -based photocatalysts are the remaining challenges for their practical applications. To address such challenges, photocatalysts consisting of AgCl covered Ag nanoparticles (AgCl@Ag), titanate nanotubes (TiNT), and nitrogen-doped reduced graphite oxide (rGO N ) are fabricated through alkaline hydrothermal process, followed by deposition and in situ surface-oxidation of silver nanoparticles. In the synthesized photocatalysts, the titanate nanotubes have average length of about 100 nm with inner diameters of about 5 nm and the size of the formed silver nanoparticles is in the range of 50–100 nm. The synthesized photocatalyst degrades almost all the model organic pollutant Rhodamine B in 35 min and remains 90% of photocatalytic efficiency after 5 degradation cycles under visible light irradiation. Since the oxidant FeCl 3 applied for oxidation of surface Ag to AgCl is difficult to be completely removed due to the high adsorption capacity of TiNT and rGO N , the effect of reside Fe atoms on photocatalytic activity is evaluated and the results reveal that the residue Fe atom only affect the initial photodegradation performance. Nevertheless, the results demonstrate that the formed composite catalyst is a promising candidate for antibiosis and remediation in aquatic environmental contamination. [ABSTRACT FROM AUTHOR]

Y 2 O 3 modified TiO 2 nanosheets (Y 2 O 3 @TNSs), capable of exhibiting sun light, were synthesized through one pot/hydrothermal method using Y (NO 3 ) 3 as precursor. Multiple techniques were applied to investigate the structures, morphologies, optical and electronic properties and photocatalytic performance of the as-prepared samples. The Y 2 O 3 @TNSs, with thickness of approximately 3–4 nm, large surface area of 240–350 m 2 /g, were full of Y 2 O 3 nanoparticles highly dispersed on the surface. The introduction of Y 2 O 3 influenced the crystallinity and the structure evolution of TNSs, besides, improved the light absorption ability. The surface photo-current and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be improved by an appropriate modification. The degradation activity of this sun-light-induced photocatalytic has enhanced apparently on 4-Chlorophenol and K 2 Cr 2 O 7 solution, the degradation efficiency of 4-Chlorophenol reached 5.69 times than that of P25, and the maximum TOC removal obtained after 120 min was 67.6%, indicating that most organic compounds were released from the solution. The enhancement in the photocatalytic activity was attributed to the synergetic effect of the Y 2 O 3 and TNSs, which led to a fast separation and slow recombination of photo-induced electron-hole pairs. Consequently, the high efficiency in the experiments showed a promising application of the catalyst in the oxidation or reduction degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

A binary heterostructured CdS/MoS 2 flowerlike composite photocatalysts was synthesized via a simple one-pot hydrothermal method. This photocatalyst demonstrated higher photocatalytic hydrogen production activity than pure MoS 2 . The heterojunction formed between MoS 2 and CdS seems to promote interfacial charge transfer (IFCT), suppress the recombination of photogenerated electron–hole pairs, and enhance the hydrogen generation. Based on the good match between the conduction band (CB) edge of CdS and that of MoS 2 , electrons in the CB of CdS can be transferred to MoS 2 easily through the heterojunction between them, which prevents the accumulation of electrons in the CB of CdS, inhibiting photocorrosion itself and greatly enhancing stability of catalyst. Hydrogen evolution reaction (HER) using Na 2 S/Na 2 SO 3 or glucose as sacrificial agents in aqueous solution was investigated. The ratio between CdS and MoS 2 plays an important role in the photocatalytic hydrogen generation. When the ratio between CdS and MoS 2 reaches 40 wt%, the photocatalyst showed a superior H 2 evolution rate of 55.0 mmol g −1 h −1 with glucose as sacrificial agent under visible light, which is 1.2 times higher than using Na 2 S/Na 2 SO 3 as sacrificial agent. Our experimental results demonstrate that MoS 2 -based binary heterostructured composites are promising for photocorrosion inhibition and highly efficient H 2 generation. [ABSTRACT FROM AUTHOR]

TiO 2 -nanosheet (TNS) was firstly fabricated using a one-pot hydrothermal route followed with photo depositing various dosages of Pt nanoparticles over its surface. The hydrogen production performance of these as-prepared samples was assessed in triehanolamine (TEOA) aqueous solutions under visible-light irradiation. The results showed the optimal ratio of Pt: TNS was 0.5 wt %, with apparent quantum efficiency (QE) climbing 15.44%. And on this basis, it was used to H 2 production simultaneous photodegradation with individual or both kinds of dyes (namely, methyl orange (MO), eosine Y (EY), methyl blue (MB) and rhedamine B (RhB)), respectively. As the figures indicated, although the rate of hydrogen production saw a steady increase in the single dye in the solution, it was outmatched by any two kinds of dyes group, which played significant positive synergism effects. In particular, when MB/EY group was added intoTEOA solution, the QE reached a peaking of 25.42% dramatically. In addition, real textile industrial wastewater was applied in this system, and the QE was 20.45%, which was 1.32 fold that of clean water. The crucial factor in improving the photocatalytic activity was that appropriate amount of functional 0D-2D Schottky barrier heterostructures were constructed. Such a novel architecture provided a large and intimate contact interface for fast interfacial photo-charges separation. The effective charge transfer from TNS to Pt was demonstrated by the significant enhancement of photocurrent responses in 0D-2D Pt-TNS composite. This work created new opportunities for designing and constructing highly efficient photocatalysts by interfacial engineering. [ABSTRACT FROM AUTHOR]

TiO 2 -based nanosheets (TNSs) co-modified by Fe 2 O 3 and Ho 2 O 3 were synthesized by one-pot hydrothermal method using Fe(NO 3 ) 3 and Ho(NO 3 ) 3 as precursors compositing with TiO 2 . The Fe 2 O 3 /Ho 2 O 3 -TNSs heterojunctions possessed a thickness of approximately 3–4 nm, large specific surface area of 210–310 cm 2 /g, with Fe 2 O 3 and Ho 2 O 3 nanoparticles highly dispersed over the surface of the nanosheets. The crystallization of the samples gradually increased with the amount of Fe 2 O 3 nanoparticles, which was confirmed by the XRD, BET and Raman spectra, indicating that Ho 2 O 3 and Fe 2 O 3 influenced the crystallinity and structure evolution of the TNSs, besides, led to an improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be efficiently improved by an appropriate amount of modification. The Fe 2 O 3 /Ho 2 O 3 -TNSs exhibited synergistic effect on photocatalytic degradation of RhB as well as MO under visible light. The highest efficiency was obtained by 0.05%-Fe 2 O 3 /Ho 2 O 3 -TNSs (Fe:Ho:Ti = 0.05:1:100), which was 8.86 and 6.72 times than that of individual 1.0%-Ho 2 O 3 -TNSs (Ho:Ti = 1:100) and 0.05%-Fe 2 O 3 -TNSs (Fe:Ti = 0.05:100), respectively. The possible mechanism for enhanced visible-light-induced photocatalytic activity was proposed. Ho 2 O 3 introduced in the photocatalysts may act as the hole capture while Fe 2 O 3 may share the same Fermi levels with TNSs and serve as the electron capture center in the n-n-p system, which reduced the recombination rate of photo-induced electron-hole pairs. [ABSTRACT FROM AUTHOR]

Visible-light-driven (VLD) CoO x loaded TiO 2 -based nanosheets (Co-TNSs) with surface-enrich CoO x nanoparticles were successfully synthesized by using a facile one-pot hydrothermal method. The photocatalysts were characterized by SEM, AFM, HRTEM, XRD, Raman, XPS, FL and the surface photocurrent (SPC) technique, etc. The as-synthesized samples exhibit sheet-like structure with large specific surface area (260–350 cm 2 /g) and small thickness (3–4 nm). The CoO x nanoparticles (1–2 nm) are highly dispersed on the surface of TNSs. Loaded CoO x nanoparticles not only have influenced the crystal structure, crystallinity and surface area of the TNSs, but also resulted in considerable enhancement of visible-light (VL) absorption and a red-shift of the band gap of the TNSs. XPS results reveal that cobalt mainly exists in the form of Co 2+ and Co 3+ , and the binding energies of Ti O bonds are changing with the loaded amount of CoO x nanoparticles. FL and SPC results indicate appropriate amount of CoO x (2.5 at.%) loading can effectively inhibit the recombination of photo-generated electron-hole pairs, thus improve the separation efficiency of charge carriers. The photocatalytic activity of the samples was evaluated by the dichromate (Cr(VI)) solution under VL irradiation. It can be found that the Co-TNSs photocatalysts showed excellent VL photocatalytic activity for the removal of Cr(VI). Initially the photocatalytic activity increased with the content of CoO x , and then decreased after attaining a maximum value at an optimal content (2.5 at.%) for degradation of aqueous Cr(VI) solution. The addition of Ca 2+ promotes photocatalysis owing to its ionic bridging function in the form of TiOH + Cr(VI)–Ca 2+ Cr(VI) linkages, while SO 4 2− slightly inhibits the photo-reduction of Cr(VI), indicating good synergy of photocatalysis and adsorption even at higher ionic strength of electrolyte. The photocatalytic reduction of Cr(VI) is also significantly promoted by phenol and synergism between Cr(VI) reduction and degradation of phenol which is demonstrated by measuring the effect of multiple usage of Co-TNSs on its photocatalytic efficiency. Desorbed Co-TNSs (Co-TNSs-Des) are easily regenerated and reused for Cr(VI) removal with excellent performance. A possible alternate mechanism for the enhancement of photocatalytic activity under visible light irradiation is also proposed. [ABSTRACT FROM AUTHOR]

Ultrathin TiO 2 -based nanosheets (TNSs) are prepared by a novel and facile hydrothermal route. It is found that TiO 2 nanoparticles can be completely converted into layered titanate structure when they are first treated with high concentrated NaOH solution, which is crucial to hinder the formation of tube-like structure and facilitate the final synthesis of pure sheet-like structure. Besides, ultrathin TNSs composed of 1–3 monolayers with an interlayer spacing of ca. 1.02 nm can be obtained by a further treatment of exfoliation. The prepared TNSs exhibit much higher photocatalytic activity than commercial P25 TiO 2 . Owing to the advantages of uniform morphology, ultrathin thickness, and high charge-separation efficiency, the obtained TNSs may have a wide application prospect in photocatalysis and some related fields. [ABSTRACT FROM AUTHOR]

Abstract: TiO2-based nanosheet (TNS) was modified with Ag2O, and the adsorption and photocatalytic performances of modified nanosheet were characterized by the removal of high-concentration methylene blue (MB). When TNS was loaded with a proper amount of Ag2O, the adsorption capacity is enhanced to 2.2 times, with a maximum of 172.4mg/g determined from Langmuir isotherm. The adsorption results also show that a small amount of Ag2O-modified TNS can quickly enrich large amounts of MB molecules onto its surface via adsorption. Furthermore, Ag2O-modified TNS exhibits novel separation efficiency of photogenerated carriers evidenced by photoluminescence measurements, and enhanced photocatalytic activity proved by the degradation of MB. The good reusability of Ag2O-modified TNS implies a potential application for dealing with high-concentration dyes by adsorption–photocatalytic degradation. [Copyright &y& Elsevier]

[Display omitted] • PNT was obtained via hydrothermal method and hydrolysis condensation reaction. • Absorption performance is greatly improved with the introduction of POSS. • The synergistic effect appears between methoxy-POSS and NT heterojunction. • The synergistic effect makes PNT exhibit excellent photocatalytic activities. Ni x O y (NiO, Ni 2 O 3) nanoparticles modifies titanium dioxide nanosheet (T) via one-step hydrothermal method, and then bis (vinyl)-hexa (trimethoxyethyl)-polysilsesquioxane (BH-POSS) is distributed on Ni x O y -T (NT) by utilizing hydrolysis condensation reaction procedure. Thus, BH-POSS/Ni x O y -T (PNT) is successfully obtained which exhibits boosted absorption ability and enhanced visible light photocatalytic efficiency. Above all, the maximum adsorption capacity (q m) of PNT is up to 848.458 mg/g for crystal violet (CV) within 5 min estimated by Langmuir adsorption model which is 18.7-fold larger as compared to T. Under visible light, the optimal PNT achieves the highest degradation rate constant value (K app) for rhodamine B (RhB) of 0.0150 min−1, which is 2.4-fold higher than that of NT. In addition, the present work may help us gain deeper insight into the synergistic effect between the BH-POSS that has larger absorption and NT heterojunction that accelerates electrons-holes separation and provide us with a new design route to make PNT considered as a promising material. [ABSTRACT FROM AUTHOR]

Abstract: Novel magnetic Bi2WO6/TiO2 hierarchical microspheres with grape-like morphology were successfully synthesized by a reliable and effective approach. The multifunctional composite microspheres compose of a magnetic core of Fe3O4@SiO2, and an outer shell of Bi2WO6/TiO2 heterostructure. The photocatalytic activities of the samples were evaluated by photodegradation of Rhodamine B (RhB) under visible light irradiation. It is discovered that the Fe3O4@SiO2@Bi2WO6/TiO2 (FSBT) composite microspheres exhibit superior photocatalytic activity, and the photocatalytic reaction rate reaches 0.0640min−1, which is 1.5 and 49.2 times greater than that of the Fe3O4@SiO2@Bi2WO6 (FSB) composites and the TiO2 (Degussa P25) nanoparticles, respectively. Besides, the FSBT composite microspheres also present excellent magnetic recoverability. [Copyright &y& Elsevier]