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Surface frustrated Lewis pairs (SFLPs) have been implicated in the gas‐phase heterogeneous (photo)catalytic hydrogenation of CO2 to CO and CH3OH by In2O3−x(OH)y. A key step in the reaction pathway is envisioned to be the heterolysis of H2 on a proximal Lewis acid–Lewis base pair, the SFLP, the chemistry of which is described as In⋅⋅⋅In‐OH + H2 → In‐OH2+⋅⋅⋅In‐H−. The product of the heterolysis, thought to be a protonated hydroxide Lewis base In‐OH2+ and a hydride coordinated Lewis acid In‐H−, can react with CO2 to form either CO or CH3OH. While the experimental and theoretical evidence is compelling for heterolysis of H2 on the SFLP, all conclusions derive from indirect proof, and direct observation remains lacking. Unexpectedly, we have discovered rhombohedral In2O3−x(OH)y can enable dissociation of H2 at room temperature, which allows its direct observation by several analytical techniques. The collected analytical results lean towards the heterolysis rather than the homolysis reaction pathway. [ABSTRACT FROM AUTHOR]

Surface frustrated Lewis pairs (SFLPs) have been implicated in the gas‐phase heterogeneous (photo)catalytic hydrogenation of CO2 to CO and CH3OH by In2O3−x(OH)y. A key step in the reaction pathway is envisioned to be the heterolysis of H2 on a proximal Lewis acid–Lewis base pair, the SFLP, the chemistry of which is described as In⋅⋅⋅In‐OH + H2 → In‐OH2+⋅⋅⋅In‐H−. The product of the heterolysis, thought to be a protonated hydroxide Lewis base In‐OH2+ and a hydride coordinated Lewis acid In‐H−, can react with CO2 to form either CO or CH3OH. While the experimental and theoretical evidence is compelling for heterolysis of H2 on the SFLP, all conclusions derive from indirect proof, and direct observation remains lacking. Unexpectedly, we have discovered rhombohedral In2O3−x(OH)y can enable dissociation of H2 at room temperature, which allows its direct observation by several analytical techniques. The collected analytical results lean towards the heterolysis rather than the homolysis reaction pathway. [ABSTRACT FROM AUTHOR]

Abstract Well dispersive CdS quantum dots (QDs) were successfully in-situ grown on cadmium hydroxyapatite (Cd 5 (PO 4) 3 OH, Cd-Hap) assembled rods through a self-sacrificing hydrothermal method. No any nocuous organic ligands were used in such self-sacrificing route, allowing for a green approach to prepare CdS QDs with clean surfaces and enough active sites. The deposition of CdS QDs onto Cd-Hap surfaces led to a dramatically enhanced performance in H 2 production under visible light irradiation as compared to bulk CdS nanoparticles. The optimal CdS QDs/Cd-Hap composite displayed a H 2 evolution rate of 14.1 μmol h−1 without using any noble metal cocatalyst, which was about 4.2 times higher than that of pristine CdS. The apparent quantum efficiency for CdS QDs/Cd-Hap composite was up to 18%. It was also found that CdS QDs/Cd-Hap composite can continuously generate H 2 from water in the presence of electron donors for more than 125 h. The enhanced photocatalytic performance of CdS QDs/Cd-Hap composites could be attributed to the high charge separation efficiency resulting from the efficient capture of photoinduced electrons by oxygen vacancies in Cd-Hap rods and the quantum confinement effect of CdS QDs with strong redox capacity as well as the increased active sites. Graphical abstract Image 1 Highlights • CdS QDs/Cd-Hap composites were prepared by self-sacrificing method. • CdS QDs were homogeneously grown on Cd-Hap rods surface. • No any nocuous organic ligands were used in such self-sacrificing route. • CdS QDs/Cd-Hap composite displayed a high H 2 evolution rate. [ABSTRACT FROM AUTHOR]

Zn 2 SiO 4 nanocrystallines were synthesized by a low-temperature hydrothermal method, in which the composition and morphology were tailored by changing the hydrothermal temperature and pH value. Zn 2 SiO 4 was applied as novel photocatalyst to degrade various organic pollutants and it exhibited excellent photocatalytic activity and stability as compared to traditional ZnO. The better photocatalytic performance of Zn 2 SiO 4 than ZnO can be attributed to the more generated charge carries, the stronger oxidation ability of h + and the higher concentration of active O 2 − radicals. [ABSTRACT FROM AUTHOR]

A series of Ag 2 S/Ag 3 PO 4 composites with well-defined core/shell structures were synthesized via an in-situ anion-exchange reaction between Ag 3 PO 4 dodecahedrons and Na 2 S solutions. The obtained samples were characterized by XRD, BET, AFS, SEM, TEM, EDX, XPS, DRS and PL. The Ag 2 S/Ag 3 PO 4 composites exhibited excellent photocatalytic activity towards the degradation of MO under both visible and NIR light irradiation. The optimal composite Ag 2 S-5%/Ag 3 PO 4 exhibited the highest visible-light-driven activity, which could degrade almost all MO within 120 min. Under NIR light irradiation, the Ag 2 S-50%/Ag 3 PO 4 composite showed the best photocatalytic activity and decomposed more than 30% of MO after 240 min of irradiation. Recycling experiments confirmed that the Ag 2 S/Ag 3 PO 4 composites had superior cycle performance and stability. The photocatalytic activity was highly dependent on the Ag 2 S content and the well-defined core/shell structure. The enhancement in photocatalytic activity of Ag 2 S/Ag 3 PO 4 composites could be mainly ascribed to the efficient separation of photogenerated charge carriers between the intimate interface of Ag 2 S shell and Ag 3 PO 4 core. The in-situ formed Ag nanoparticles at surfaces of Ag 3 PO 4 and Ag 2 S during photocatalytic process acted as charge transmission bridges and electron trapping centers, respectively, resulting in the stable Ag 2 S/Ag/Ag 3 PO 4 Z-scheme system and Ag/Ag 2 S/Ag 3 PO 4 ternary system. Based on the experimental results, the possible photocatalytic mechanisms for MO degradation over Ag 2 S/Ag 3 PO 4 composites under both visible and NIR light irradiation were proposed. [ABSTRACT FROM AUTHOR]

Fabrication of heterostructure photocatalysts to improve photocatalytic performance is always a hot topic in the photocatalytic field. In this paper, In2S3/In(OH)3 heterostructure photocatalysts were synthesized via a simple combination of an in situ anion exchange reaction and the hydrothermal process. The obtained heterostructures were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (UV-vis DRS) and photocurrent experiment. The photocatalytic activity of the as-formed samples was evaluated by the degradation of methyl orange (MO), salicylic acid and 4-chlorophenol aqueous solution under simulated solar light irradiation (200 nm ＜ λ ＜ 800 nm). The results showed that the photocatalytic activities of In2S3/In(OH)3 heterostructures were greatly improved as compared to single phase In(OH)3 and In2S3. The enhancement in their photocatalytic activity could be attributed to the efficient charge transfer in In2S3/In(OH)3 heterostructures, the improved light absorbance capacity and the increased surface area. As compared, In2S3/In(OH)3 displayed higher photocatalytic activity than In2S3/In2O3 at the same In2S3 content. The excellent activity of In2S3/In(OH)3 with respect to In2S3/In2O3 was mainly due to the high concentrations of ṖO2− radicals and the strong oxidation capacity (h+). The current research provides a new insight into the construction of a narrow-band-gap with a wide-band-gap to form heterostructures as promising and efficient photocatalysts for the removal of harmful organic compounds in aqueous solution. [ABSTRACT FROM AUTHOR]

Ag 3 PO 4 /In 2 S 3 composite photocatalysts with ultra–low loading of Ag 3 PO 4 (0.017 ∼ 4.89 wt %) were prepared by a facile precipitate method and characterized by XRD, SEM, TEM, HRTEM, BET, DRS and XPS techniques. The as–obtained composites were employed to degrade different kinds of organic pollutants (dyes and colorless pollutants) in aqueous solution under visible light irradiation. The Ag 3 PO 4 /In 2 S 3 composites exhibited excellent adsorption capacity and photocatalytic activity. The optimal composite with 0.086 wt % Ag 3 PO 4 content exhibited the highest photocatalytic activity, which could degrade almost all dyes (MO, MB and RhB) within 7 min of light irradiation and more than 50% of phenol and salicylic acid after 3 h of irradiation. Recycling experiments confirmed that the Ag 3 PO 4 /In 2 S 3 catalysts had superior cycle performance and structural stability. The photocatalytic activity enhancement of Ag 3 PO 4 /In 2 S 3 composites could be mainly attributed to the efficient separation of photogenerated charge carriers through a Z–scheme system composed of Ag 3 PO 4 , Ag and In 2 S 3 , in which Ag nanoparticles acted as the charge transmission bridge. The high photocatalytic stability was ascribed to the successful inhibition of the photocorrsion of both In 2 S 3 and Ag 3 PO 4 by transferring the photogenerated holes and electrons from them to Ag, respectively. This study indicated the application of Ag–Ag 3 PO 4 as cocatalyst and provided a new way to design and prepare high–efficiency and stable photocatalysts for photocatalytic decontamination of organic pollutants. [ABSTRACT FROM AUTHOR]

In this work, a simple thermal annealing route has been developed to improve the photocatalytic performance of silver orthophosphate (Ag 3 PO 4 ) photocatalyst toward organic pollutants degradation under visible light irradiation. The experimental results indicated that thermal treatment of Ag 3 PO 4 led to an obvious lattice shift towards right and significantly narrowed band gap energies due to the formation of Ag vacancies and metallic Ag during Ag 3 PO 4 decomposition. These structural variations notably affected the photocatalytic performance of Ag 3 PO 4 photocatalysts. The activity of the annealed samples was found to be significantly enhanced toward the degradation of MO dye. The highest activity was observed over the sample annealed at 400 °C, which exceeded that of pristine Ag 3 PO 4 by a factor of about 21 times. By means of photoluminescence spectroscopy and photoelectrochemical measurements, we propose that the enormous enhancement in activity was mainly attributed to the efficient separation of photogenerated electrons and holes driven by the synergistic effect of Ag vacancies and metallic Ag. The strong interaction between annealed particles also inhibited the dissolution of Ag + from Ag 3 PO 4 into aqueous solution, contributing to an improved photocatalytic stability. The strategy presented here provides an ideal platform for the design of other highly efficient and stable Ag-based photocatalysts for broad applications in the field of photocatalysis. [ABSTRACT FROM AUTHOR]

Ag 3 PO 4 dodecahedrons were post-treated by chemical etching with ammonia solution. The etched samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N 2 sorption, UV–vis diffuse reflectance spectra (UV–vis DRS), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP), photoluminescence (PL) and photocurrent experiments. The SEM results showed that upon ammonia etching, the well-defined Ag 3 PO 4 dodecahedrons changed to hollow polyhedrons with increasing etchant dosage. From the XRD, TEM, DRS and XPS results, it could be inferred that ammonia etching of Ag 3 PO 4 led to an obvious lattice shift and significantly narrowed band gap energies due to the formation of Ag vacancies and metallic Ag. These microstructural variations notably affected the photocatalytic performance of Ag 3 PO 4 photocatalysts. The activity of the etched samples was found to be significantly enhanced toward the degradation of methyl orange (MO) dye under visible light irradiation. The highest activity was observed over the sample etched by 0.15 M ammonia solution, which exceeded that of bare Ag 3 PO 4 by a factor of about 6.2 times. The reasons for the improvement of photocatalytic performance of etched samples may be that the newly formed Ag vacancies and metallic Ag improved the separation efficiency of photogenerated electrons and holes. [ABSTRACT FROM AUTHOR]

Two Ag 3 PO 4 photocatalysts were prepared using different silver precursors (CH 3 COOAg and AgNO 3 ) and then thermally annealed in air at various temperatures. The surface chemistry of the pristine Ag 3 PO 4 photocatalysts was quite different: the Ag 3 PO 4 sample (AP-C) prepared from CH 3 COOAg possessed excessive acetate species on its surface while that (AP-N) derived from AgNO 3 showed a clean surface. The residual acetate species played crucial role in the thermally excited decomposition of Ag 3 PO 4 into metallic Ag and the simultaneous formation of Ag vacancies. The photocatalytic activity of the pristine AP-C sample was greatly improved after thermal treatment due to the synergistic effect of Ag vacancies and metallic Ag, which contributed to the efficient separation of photogenerated charge carriers. On the contrary, for the AP-N sample, the photocatalytic activity was largely weakened upon thermal annealing because the negative changes in textural structures. Of importance, after impregnation of AP-N in acetic acid solution and annealing, the photocatalytic activity was largely improved. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hierarchical TiO2 microspheres assembled by nanowires bundles were synthesized. [•] Annealing and ultrasonic irradiation had great effect on the structures of TiO2. [•] The microcavity structure of hierarchical TiO2 was destroyed upon both treatments. [•] The disappearance of microcavity structure reduced the photocatalytic activity. [ABSTRACT FROM AUTHOR]

Abstract: Ag/AgBr/BiOBr hollow hierarchical microspheres were synthesized through a one-pot solvothermal process. The phase structure, morphology and optical property of the samples were characterized by XRD, SEM, XPS and DRS. Ag/AgBr/BiOBr hollow microspheres exhibited higher photocatalytic activity and improved stability than AgBr/BiOBr nanoplates for rhodamine B degradation under visible light irradiation. The enhanced activities of Ag/AgBr/BiOBr could be attributed to the hollow structure and Ag deposition, which is favorable for adsorption of reactants, enhancement of photoadsorption and transfer of photogenerated carriers. Ag deposition also prevented the decomposition of AgBr under light illumination and contributed to an improved stability. [Copyright &y& Elsevier]

Highlights: [•] Ag/AgBr composites were synthesized by a facile one-step solvothermal route. [•] Ag was in situ anchored on the surface of AgBr. [•] Ag nanoparticles could be controlled by changing the experimental parameters. [•] The activity of Ag/AgBr composites was dependent on the Ag component. [•] Ag suppressed the decomposition of AgBr and improved its photocatalytic stability. [ABSTRACT FROM AUTHOR]

Hierarchical SnInS microspheres were successfully fabricated via a solvothermal method without the assistance of any templates or surfactants. These microspheres were of a new tetragonal polymorph, distinct from the cubic counterpart popularly reported in the literature. Systematic characterization indicated that these microspheres exhibited a diameter of 2-4 μm and were assembled by numerous interconnected nanosheets of 40 nm thickness. The formation mechanism of hierarchical SnInS microspheres was proposed by taking into account the influences of experimental conditions on the morphology and structure. Hierarchical microspheres possessed a large specific surface area of 197 m g and an accessible porous configuration, which gave rise to an excellent visible light-driven photocatalytic efficiency for methyl orange degradation in aqueous solutions, superior to that for the known N-doped TiO photocatalyst. [ABSTRACT FROM AUTHOR]

Abstract: Porous SnIn4S8 microspheres were initially synthesized through a facile solvothermal approach and were investigated as visible-light driven photocatalysts for dyes degradation in polluted water. The photocatalysts were characterized by XRD, SEM, TEM, N2 adsorption–desorption, and UV–vis diffuse reflectance techniques. Results demonstrated that the as-synthesized SnIn4S8 was of a new tetragonal polymorph, showing a band-gap of 2.5eV, a specific surface area of 197m2 g−1, and an accessible porous structure as well. The photocatalytic activity of the porous SnIn4S8 was evaluated by decomposition of several typical organic dyes including methyl orange, rhodamine B, and methylene blue in aqueous solution under visible light irradiation. It is demonstrated that porous SnIn4S8 was highly photoactive and stable for dyes degradation, showing photocatalytic activity much higher than binary constituent sulfides like In2S3, SnS2, or even ternary chalcogenide ZnIn2S4 photocatalyst. The excellent photocatalytic performance of porous SnIn4S8 is the consequence of its high surface area, well-defined porous texture, and large amount of hydroxyl radicals. [Copyright &y& Elsevier]

Abstract: This work explored the selective synthesis of polymorphs of CdWO4 in either tetragonal or monoclinic phase by optimizing the experimental parameters. Systematic characterization indicated that both polymorphs possessed similar spherical morphologies but different structural building blocks. Electronic structures calculations for both polymorphs demonstrated the same constructions of conduction band or valence band, while the conduction band widths of both polymorphs were quite different. Both CdWO4 polymorphs exhibited good photocatalytic activity for degradation of methyl orange under UV light irradiation. When comparing to some other well-known tungstate oxide materials, the photocatalytic activity was found to follow such a consequence, monoclinic CdWO4≈monoclinic ZnWO4>tetragonal CdWO4>tetragonal CaWO4. The specific photocatalytic activity of monoclinic CdWO4 was even higher than that of commercial TiO2 photocatalyst (Degussa P25). The increased activity from the tetragonal CdWO4 to the monoclinic was consistent with the trend of the decreased symmetry, and this could be explained in terms of the geometric structures and electronic structures for both polymorphs. [Copyright &y& Elsevier]

Abstract: Nearly monodisperse single-crystalline In(OH)3 nanocubes were successfully synthesized using In(NO3)3⋅4.5H2O as indium source in the presence of urea and cetyltrimethyl ammonium bromide (CTAB) by a two-step hydrothermal process: the stock solution was heated at 70 °C for 24 h and then at 120 °C for 12 h. The structure and morphology of the resultant In(OH)3 samples were determined by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results revealed that most of as-synthesized In(OH)3 nanocubes were uniform in size, with the average edge length of ∼700 nm. The influences of the reaction temperature, the reaction time, the mineralizer, and the surfactant on the morphology of the obtained products were discussed in detail. Room-temperature photoluminescence (PL) spectrum of the In(OH)3 nanocubes showed a peculiar strong emission peak centered at 480 nm. Furthermore, the photocatalytic properties of the In(OH)3 nanocubes were tested. It was found that In(OH)3 exhibited not only higher activity for benzene removal, but also better H2 evolution from water than the commercial Degussa P25 TiO2. [Copyright &y& Elsevier]

Abstract: A novel photocatalyst In(OH)3 was synthesized by peptization of a colloidal precipitate under ultrasound radiation. The photocatalyst was characterized by N2 adsorption, XPS, XRD, UV–vis DRS, and FTIR technologies. The photocatalyst sample is highly photoactive and stable for gas-phase removal of benzene under UV irradiation, even in dry O2 atmosphere. Both the conversion of benzene and the mineralization yield are notably accelerated, as compared to the widely used photocatalyst – titania (Degussa P25). In(OH)3 is active even after 30h of photoreaction. The maximal conversion and mineralization ratio of benzene achieved are 33.4% and 56%, respectively, which is much higher than that obtained with TiO2 (9.5% and 24%). The high activity and durability of the In(OH)3 can be ascribed to the high hole oxidation potential and carbon deposits formed uneasily on the catalyst surface. [Copyright &y& Elsevier]

CoMnHCF is utilized in aqueous sodium/zinc mixed ion batteries and exhibits a high reversible capacity with good rate and cycle performances. At 0.05 A g−1 current density, the CoMnHCF can deliver a specific capacity for 180.4 mA h g−1, and have 99.3% capacity retention after 300 cycles at 0.3 A g−1. Such high reversible capacity profits from Mn vacancies that generate in situ during the first cycle, which provides more active sites for Zn storage. The de-intercalation of Na+ further elevates this good electrochemical performance. Co atoms in the framework are not only involved in the redox reactions, but help to support the structure, thus achieving better cycle stabilities. [ABSTRACT FROM AUTHOR]

In this paper, Sm3+-activated K 2 BaPO 4 F red phosphors were prepared by a traditional solid-state reaction method. The crystal structure and emission enhancement mechanism of the materials were systematically investigated. The photoluminescence intensity, chromaticity, lifetime, and fluorescence thermal stability were evaluated in detail. The emission intensity and quantum efficiency were significantly improved by the introduction of Na + ions. The lattice parameters of the K 2 BaPO 4 F, K 2 Ba 0.975 PO 4 F:0.025Sm3+, and Na-doped K 2 Ba 0.975 PO 4 F:0.025Sm3+ phosphors were investigated through the Rietveld refinement method. With the occupation of K+ sites by Na+ ions, the reduced volume of the unit cell increased the quantum efficiency of Sm3+ ions about 2.5 times. The present work demonstrates that the modified K 2-2x Na 2x Ba 0.975 PO 4 F:0.025Sm3+ orange-red phosphors are expected to be used in white light-emitting diodes (w-LEDs). [ABSTRACT FROM AUTHOR]

In this paper, Sm3+-activated K 2 BaPO 4 F red phosphors were prepared by a traditional solid-state reaction method. The crystal structure and emission enhancement mechanism of the materials were systematically investigated. The photoluminescence intensity, chromaticity, lifetime, and fluorescence thermal stability were evaluated in detail. The emission intensity and quantum efficiency were significantly improved by the introduction of Na + ions. The lattice parameters of the K 2 BaPO 4 F, K 2 Ba 0.975 PO 4 F:0.025Sm3+, and Na-doped K 2 Ba 0.975 PO 4 F:0.025Sm3+ phosphors were investigated through the Rietveld refinement method. With the occupation of K+ sites by Na+ ions, the reduced volume of the unit cell increased the quantum efficiency of Sm3+ ions about 2.5 times. The present work demonstrates that the modified K 2-2x Na 2x Ba 0.975 PO 4 F:0.025Sm3+ orange-red phosphors are expected to be used in white light-emitting diodes (w-LEDs). [ABSTRACT FROM AUTHOR]

The novel BiVO 4 nanofibers were firstly obtained by two-step synthesis method. Characterized by X-ray diffractometer (XRD) and scanning electron microscopy (SEM), the samples were shown to be nanofibers with monoclinic phase. The ethylene glycol (EG) and NaOH solution played an important role on their formation. Taking rhodamine B (RhB) as the removal object, the nanofibers exhibited the enhanced adsorptive activity compared with other samples. It may be due to the increase of the specific surface area, the acidic surface property of the BiVO 4 nanofibers and the nature of the RhB dye. The formation mechanism of the special morphology was investigated and proposed. It is expected to provide some guidance for designing and preparing other materials for removal of organic pollutants. [ABSTRACT FROM AUTHOR]

In this work, a novel, earth-abundant, and environmentally benign NaFeSi2O6 catalyst is synthesized by a one-step solvothermal method without the introduction of any surfactants. NaFeSi2O6 is for the first time applied to the heterogeneous photo-Fenton reaction for the degradation of RhB under visible-light irradiation with long-term stability and a wide working pH range. ˙OH plays the most important role in the photo-Fenton process. Besides, ˙O2− and h+ are also generated and involved in this reaction simultaneously. Combining the experimental results and theoretical calculations, it can be confirmed that NaFeSi2O6 can be regarded as a promising catalyst to improve the efficiency of the heterogeneous photo-Fenton reaction. [ABSTRACT FROM AUTHOR]

In this paper, Er3+/Yb3+ co-doped CdMoO4 phosphors were prepared by a traditional high temperature solid state reaction method. Based on the 3D network structure of the CdMoO4 host and the efficient Er3+/Yb3+ upconversion luminescence combinations, excellent green emission properties were observed when the prepared sample is irradiated with a laser at about 980 nm. For optical temperature sensors based on the fluorescence intensity ratio (FIR), the prepared phosphors have excellent sensitivity to temperature in the range of 293 to 473 K. With increasing environmental temperatures, the absolute sensitivity of the CdMoO4:0.02Er3+,0.08Yb3+ sample reached a maximum at about 473 K (Sa = 1.388% K−1). The calculated relative sensitivity of the optical temperature sensor was Sr = 1.631% K−1 at 293 K. This is due to the sensitive thermally coupled energy levels (TCLs) of the Er3+ ions (2H11/2 and 4S3/2) in the CdMoO4 structure. Therefore, it is shown that the prepared CdMoO4:0.02Er3+,0.08Yb3+ phosphor has excellent applications in non-contact optical temperature measurement. [ABSTRACT FROM AUTHOR]

Both theories and experiments show that surface hydroxyl radicals ( OH) are the most important intermediate species in the photocatalytic process. As a source of OH, surface hydroxyl (OH) groups play an important role in its generation. In this paper, the OH groups were divided into surface acidic hydroxyl (OH(a)) and surface basic hydroxyl (OH(b)) groups. From the detection by a method of surface acid–base, ion-exchange reactions, the total surface density of OH groups was about 9.58 × 10 −5 mol m −2 . The results measured by Fourier transform infrared spectroscopy, 1 H magnetic-angle spinning NMR and electron spin resonance techniques demonstrated that the role of OH(a) groups was greater than that of OH(b) groups on the generation of OH radicals. By degradation of methyl orange, rhodamine B and p-chlorophenol, the photocatalytic activities of the catalysts were directly influenced by the amount of OH groups. [ABSTRACT FROM AUTHOR]

Doping magnetic elements into semiconductors is an effective strategy for manipulating spin-polarized electrons in photocatalysis. This work indicates that the introduction of spin-polarized electrons into BiOCl ultrathin sheets remarkably boosts the efficiency of photocatalytic CO 2 reduction by doping BiOCl with magnetic Co. The Co-doped BiOCl (Co-BiOCl) photocatalyst selectively converts CO 2 into CH 4 and C 2+ products with a hydrocarbon selectivity of 76.9 %, which is not available for pristine BiOCl. The spin-polarized electrons generated from Co-BiOCl promote CO adsorption, stabilize the key CO* intermediate, and significantly reduce the kinetic barrier to CH 2 * formation, tuning the subsequent hydrogenation and C−C coupling into hydrocarbons. The regulatory effect of spin polarization on photocatalytic CO 2 reduction can also be observed for Fe-, Ni- or non-magnetic element Cu- doped BiOCl. Hence, this work provides new insight into the regulation of the photoreduction of CO 2 to hydrocarbon products by spin-polarized electrons. [Display omitted] • Co doping introduces spin-polarized electrons in BiOCl ultrathin sheets. • Co-BiOCl selectively converts CO 2 into CH 4 and C 2+ products. • Spin-polarized electrons generated from Co-BiOCl promote CO adsorption. • Spin-polarized electrons benefit for stabilizing the reaction intermediates. • The regulatory effect is also observed on Fe-, Ni- or Cu- doped BiOCl. [ABSTRACT FROM AUTHOR]

• Strong near ultraviolet emission with high thermal stability was been observed in Ce3+ doped K 2 BaPO 4 F phosphors. • DFT calculations based on refined crystal structure were performed. • The concentration quenching mechanism was confirmed. • The high thermal stability is ascribed to the large band gaps, small phonon energy and rigid lattice structure. Novel K 2 BaPO 4 F:Ce3+ phosphors with strong violet-emission and high thermostability were synthesized by a traditional high-temperature solid-state reaction method. The phase composition and crystal structure were investigated in detail by XRD refinement. DFT calculations based on refined crystal structure were performed. A bright emission in the range of 340–390 nm with a small Stokes shift has been observed when excited at about 323 nm in K 2 BaPO 4 F:Ce3+ phosphors. The temperature-dependent PL spectra from 80 to 500 K were investigated systematically. The best doping concentration of K 2 BaPO 4 F:xCe3+ phosphors was verified and the concentration quenching mechanism was also confirmed. When the temperature increased from 80 K to 500 K, the emission intensity still remains 53 %. The thermal quenching mechanism was explained using the crystal structure investigation and DFT calculation. The strong near-ultraviolet emission intensity and ultra-high thermal stability indicating that the prepared K 2 BaPO 4 F:Ce3+ phosphors have potential applications in anti-counterfeiting and solid-state lighting. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • CdS/CdWO 4 heterojunction photocatalysts based on two crystal forms of CdWO 4 were synthesized via an in-situ anion-exchange reaction. • CdS/M-CdWO 4 follows the traditional type II charge transfer mechanism. • For CdS/T-CdWO 4 with oxygen vacancies, the charge transfer shifts to S-scheme transport mechanism. • Compared to CdS/M-CdWO 4 , the CdS/T-CdWO 4 gives a 14-fold enhanced H 2 evolution rate under the full spectrum irradiation. • It realized improved photocatalytic performance from the point of polycrystalline engineering and surface defects. Regulation of the carrier migration path in heterojunction photocatalysts is an effective strategy to improve the performance of photocatalytic hydrogen evolution. Herein, CdS/CdWO 4 heterojunction photocatalysts based on two crystal forms of CdWO 4 were synthesized via an in-situ anion-exchange reaction. It was discovered that crystal structure and surface defect have a significant impact on the charge carrier migration mechanism during photocatalysis. When CdS was loaded onto monoclinic CdWO 4 (M-CdWO 4), the resulting CdS/M-CdWO 4 heterojunction followed the conventional type- II charge transfer mechanism. In contrast, tetragonal CdWO 4 (T-CdWO 4) with a substantial number of oxygen vacancies resulted in the CdS/T-CdWO 4 composite adopting an S-scheme transport mechanism. Driven by the distinct carrier migration path, the CdS/T-CdWO 4 heterojunction demonstrated superior hydrogen evolution performance compared to the CdS/M-CdWO 4. Significantly, the hydrogen evolution rate of CdS/T-CdWO 4 was 2.56 mmol h−1 g−1, which is about 14 times higher than CdS/M-CdWO 4. The excellent photocatalytic activity of CdS/T-CdWO 4 could be mainly ascribed to the efficient separation of photogenerated charge carriers and the higher reduction capacity showcasing in S-scheme. Several techniques such as electron paramagnetic resonance (EPR), in-situ X-ray photoelectron spectroscopy (XPS), and selective photodeposition were employed to confirm the regulation of the carrier migration path from type II to S-scheme over CdS-loaded CdWO 4 polymorphs. This study provides comprehensive insights into the construction of highly efficient photocatalytic heterojunctions in the viewpoint of polymorph engineering and surface defects from a deeper perspective. [ABSTRACT FROM AUTHOR]

Through a solid-phase reaction technique, Sm3+ and Bi3+ co-doped La3BWO9 phosphors with high emission intensity and sensitive temperature sensing properties have been successfully synthesized. Based on XRD Rietveld refinement, the optimized crystal structure was used as the original model to calculate the band structure and partial density of states (PDOS) by density functional theory (DFT) calculations. The luminescence characteristics of Sm3+ and Bi3+ co-doped La3BWO9 phosphors were measured and analyzed. In addition, the optimal doping concentrations of Sm3+ and Bi3+ were investigated. The luminescence properties of Sm3+ doped phosphors were optimized by introducing Bi3+ ions. Efficient energy transfer from Bi3+ to Sm3+ ions was observed in La3BWO9:Sm3+, Bi3+ phosphors. An optical temperature sensor with high sensitivity was designed based on the different thermal quenching properties of Sm3+ and Bi3+ ions. In the temperature range of 293–498 K, the optimum absolute sensitivity (Sa) and maximum relative sensitivity (Sr) were 2.88 %K−1 and 1.32 %K−1, respectively. These results indicated that the prepared La3BWO9:Bi3+, Sm3+ phosphors have wide application prospects as solid state lighting materials and optical temperature sensors. [ABSTRACT FROM AUTHOR]

The novel Z‐scheme photocatalytic system of In2O3/OV/In2S3 has been obtained by a facile two‐step in situ deposition method, where oxygen vacancies and In2S3 are in situ located on the surface of In2O3 in sequence. In such a photocatalytic system, oxygen vacancy anchored tightly on the surface of In2O3 serves as an electron mediator, efficiently extracting electrons from In2O3 and modulating the electron transfer paths to facilize constructing a Z‐scheme system. Due to the presence of another tight contact interface between the In2O3 and In2S3, the transfer rate of electrons from In2O3 to In2S3 can be further accelerated. Therefore, the synergistic effect of the above‐mentioned dual‐tight contact interface over In2O3/OV/In2S3 Z‐scheme system simultaneously enhances the charge separation and transfer, resulting in the high performance of photocatalytic H2 evolution. [ABSTRACT FROM AUTHOR]

Graphdiyne (GDY) is firstly introduced to the gaseous photocatalytic CO 2 hydrogenation system for C 2+ production, in which a GDY-modified In 2 O 3 nanocomposite (denoted as GDY-IO) is fabricated by simple electrostatic attraction and thermal treatment routes. GDY-IO delivers much higher performance for CO 2 hydrogenation compared to that of pristine In 2 O 3 , reflecting by the significantly improved C 1 (CO and CH 4) yield and the newly formed C 2+ hydrocarbons (C 2 H 4 , C 2 H 6 , C 3 H 6 , and C 3 H 8). The introduction of GDY promotes the transport of photogenerated holes from In 2 O 3 to GDY and suppresses the recombination of photogenerated carriers, thereby gathering abundant electrons to participate in the CO 2 hydrogenation reaction. GDY-IO interface may stabilize the key HOCH* intermediate and significantly reduce the kinetics barrier to avail CH* formation, tuning the subsequent hydrogenation and C-C coupling into thermodynamically favorable exothermal processes. This research develops a new avenue for synthesis of high value-added chemical fuels from greenhouse gases by graphdiyne-based photocatalysis. [Display omitted] • Graphdiyne is firstly introduced to gaseous photocatalytic CO 2 hydrogenation for C 2+ production. • GDY-modified In 2 O 3 nanocomposite is fabricated by simple routes. • GDY promotes the transport of photogenerated holes from In 2 O 3 to GDY. • GDY-IO interface significantly reduces the kinetics barrier to avail CH* formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Outline the mechanism of pollutant degradation via 2D nanomaterial photocatalysts. • Summarize strategies for preparing and modifying 2D nanomaterial photocatalysts. • Present approaches for modulating the band structure and principles of improvement. • Elucidate the methods and mechanisms for constructing various heterojunctions. • Summarize experimental approaches for pollutant removal from lab-scale to grand-scale. 2D nanomaterials display unique properties for photocatalytic energy conversion and for the treatment of water and air pollution thanks to their characteristic atomic structure and physicochemical properties. A deeper understanding of the structure–property relationships of photocatalysts constructed with 2D nanomaterials is of great significance for the development of new-generation high-performance photocatalysts. In this review, detailed mechanisms of photocatalytic reaction processes and pollutant degradation by 2D nanomaterial-based photocatalysts are outlined. Subsequently, preparation strategies and various modification approaches including elemental doping, defect design, and heterostructure construction are presented, together with the principle of modulating the energy-band structure of electrode materials. Methods for the construction of heterojunctions with various configurations based on 2D nanomaterials are elucidated. Current experimental evaluations and approaches for pollutant removal are summarized, showing the use of different types of photoreactors, from lab-scale to grand-scale. Finally, the opportunities and challenges for 2D nanomaterial-based photocatalysts for pollutant degradation are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • In 2 S 3 /In 2 O 3 heterojunctions were in-situ formed and decorated on rGO sheets. • IS/IO-rGO improved the conversion of CO 2 to CO, CH 4 and C 2+ hydrocarbons. • Multiple electron transport channels between IS/IO and rGO played a great role. • It realized low charge carrier loss and high electron transfer rate on IS/IO-rGO. Constructing hybrids to accelerate the charge carrier separation and electron transport, and then decrease the electrons loss should be effective in the CO 2 conversion into C 2+ hydrocarbon fuels. In 2 S 3 /In 2 O 3 (IS/IO) heterojunctions were in situ formed and decorated on reduced graphene oxide (rGO) sheets, realizing the construction of multiple channels for electron transport. Upon illumination, IS/IO-rGO nanocomposites not only significantly improved the conversion of CO 2 to CO and CH 4 , but also allowed the formation of C 2+ hydrocarbons (C 2 H 4 , C 2 H 6 , C 3 H 6 and C 3 H 8) under atmospheric conditions, and the total selectivity of C 2+ even reached about 35 %. The synergistic effect of the heterojunctions and rGO, with multiple channels for electron transport, accelerates the charge carrier separation/transfer and increases the applied efficiency of electrons, availing more electrons accumulated on the surface of the composite. Eventually, there are sufficient electrons to participate in the reduction of CO 2 to CO, CH 4 and C 2+ hydrocarbons. [ABSTRACT FROM AUTHOR]

Black liquor, an industrial waste product of papermaking, is primarily used as a low‐grade combustible energy source. Despite its high lignin content, the potential utility of black liquor as a feedstock in products manufacturing, remains to be exploited. Demonstrated here in is the use of black liquor as a primary feed‐stock for synthesizing graphene quantum dots that exhibit both up‐conversion and photoluminescence when excited using visible/near‐infrared radiation, thereby enabling the photosensitization of ultraviolet‐absorbing TiO2 nanosheets. In addition, these graphene quantum dots can trap photo‐generated electrons to realize the effective separation of electron‐hole pairs. Together, these two processes facilitate the solar‐powered generation of H2 from H2O, and CO from H2O–CO2, using broadband solar radiation. [ABSTRACT FROM AUTHOR]

Black liquor, an industrial waste product of papermaking, is primarily used as a low‐grade combustible energy source. Despite its high lignin content, the potential utility of black liquor as a feedstock in products manufacturing, remains to be exploited. Demonstrated here in is the use of black liquor as a primary feed‐stock for synthesizing graphene quantum dots that exhibit both up‐conversion and photoluminescence when excited using visible/near‐infrared radiation, thereby enabling the photosensitization of ultraviolet‐absorbing TiO2 nanosheets. In addition, these graphene quantum dots can trap photo‐generated electrons to realize the effective separation of electron‐hole pairs. Together, these two processes facilitate the solar‐powered generation of H2 from H2O, and CO from H2O–CO2, using broadband solar radiation. [ABSTRACT FROM AUTHOR]

In this paper, a new scheme of optical temperature measurement based on Boltzmann function is reported for the first time. The BiZn 2 PO 6 and BiZn 2 PO 6 :Eu3+ phosphors with strong host emission intensity were investigated from the perspective of crystal structure, electronic band structure, phonon distribution, and fluorescence properties. By exploring the relationship between host emission intensity and temperature, or between fluorescence lifetime and temperature, a novel optical temperature sensor based on Boltzmann function was designed. With this scheme, the performance of the optical temperature sensors can be visualized in the fitting results of Boltzmann function. The absolute sensitivity of the optical temperature sensor designed based on this function reaches a maximum value S a = 1 4 d T at T 0 , while relative sensitivity is 1 2 d T . For example, in BiZn 2 PO 6 phosphor, the absolute and relative sensitivities reached 0.88% and 1.78% at 260 K. Therefore, the new optical temperature sensor based on Boltzmann function provides the theoretical basis and practical experience for the development of high-sensitivity non-contact optical temperature sensor. • Pure BiZn 2 PO 6 and Eu3+ doped phosphors with strong host emission were prepared. • The variation of emission intensity and lifetime as a function of ambient temperature follows the Boltzmann distribution. • The Sr and Sa of the optical temperature sensors can be visualized in the fitting results. • Strong red emission can be used as a reference to assist in temperature measurement. [ABSTRACT FROM AUTHOR]

Visible-light-induced dendritic BiVO 4 /TiO 2 photocatalysts have been successfully synthesized via a composite hydrothermal and sol-gel method. Evaluated by the degradation of methylene blue (MB) under visible-light irradiation (420 nm < λ < 800 nm), the sample with ratio of BiVO 4 /TiO 2 (mass ratio) equal to 60% prepared at 400 °C exhibited the best photocatalytic activity. The appropriate band gap (BiVO 4 provided) availed the absorption of visible light and the larger surface area (TiO 2 provided) enhanced the adsorption ability towards the pollutants, resulting in the high separation ratio of the electrons and holes generated. Through further detecting the degradation mechanism, it was proposed a new idea that the best activity mainly depended on the synergistic effect of photocatalysis and photosensitization. The active species generated in the degradation processes were mainly derived from BiVO 4 and MB, while TiO 2 was just the transporter of charge carriers. Some evidence has been provided to support this conclusion in detail. These results would be useful to develop highly efficient photocatalysts and helpful to reveal the degradation mechanism clearly. [ABSTRACT FROM AUTHOR]

Visible-light-induced BiVO 4 microspheres with different crystalline phases have been successfully synthesized via simple thermal treatment methods. The photocatalytic activities of the samples were evaluated by the degradation of methylene blue (MB) under visible-light irradiation (420 nm < λ < 800 nm). The results indicated that the BiVO 4 sample prepared at 400 °C, which was composed of mixed crystalline phases (tetragonal and monoclinic BiVO 4 ), exhibited the best activity. Through the detection of the degradation mechanism, it was found that the mixed phases availed the transfer of electrons and led to the generation of more kinds and amount of active species in the degradation process. The active species enhanced the photocatalytic activity. These results would be useful to develop highly efficient photocatalysts and helpful to reveal the degradation mechanism clearly. [ABSTRACT FROM AUTHOR]

BiOClxBr1−x sheets were synthesized by a simple precipitation method. These samples showed good activities in the degradation of rhodamine B (RhB) under visible light irradiation (420 nm ＜ λ ＜ 800 nm). From a series of characterization techniques, the results showed that the degradation was driven by the photosensitization of RhB and photocatalysis of BiOClxBr1−x. The mechanism of the synergistic degradation processes was explored by comparing the degradation properties of BiOClxBr1−x (Cl : Br = 1 : 1) and BiOBr. The main active species that played important roles in the degradation process were electrons and O2Ṗ− in the BiOClxBr1−x (Cl : Br = 1 : 1) system, while in the BiOBr system, electrons, O2Ṗ− and holes were the main active species. Such a heterogeneous synergistic degradation reaction has much significance in revealing the degradation mechanism of organic pollutants in ordinary photocatalysis. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ca3Bi8O15 rods were synthesized by a hydrothermal method. [•] They can utilize the sunlight efficiently with the small band-gap. [•] They showed good photocatalytic activities in the degradation of MO, RhB and 4-CP. [•] The conversion ratio of MO was up to 90% after 2h of visible light irradiation. [ABSTRACT FROM AUTHOR]

Abstract: In this work, hierarchical CuO hollow microspheres were hydrothermally prepared without use of any surfactants or templates. By controlling the formation reaction conditions and monitoring the relevant reaction processes using time-dependent experiments, it is demonstrated that hierarchical CuO microspheres with hollow interiors were formed through self-wrapping of a single layer of radically oriented CuO nanorods, and that hierarchical spheres could be tuned to show different morphologies and microstructures. As a consequence, the formation mechanism was proposed to proceed via a combined process of self-assembly and Ostwald''s ripening. Further, these hollow microspheres were initiated as the anode material in lithium ion batteries, which showed excellent cycle performance and enhanced lithium storage capacity, most likely because of the synergetic effect of small diffusion lengths in building blocks of nanorods and proper void space that buffers the volume expansion. The strategy reported in this work is reproducible, which may help to significantly improve the electrochemical performance of transition metal oxide-based anode materials via designing the hollow structures necessary for developing lithium ion batteries and the relevant technologies. [Copyright &y& Elsevier]

Abstract: Nanosized Zn2SnO4 (ZTO) particles were successfully synthesized by a simple hydrothermal process in water/ethylene glycol mixed solution using amines (ethylamine, n-butylamine, n-hexylamine, and n-octylamine) as mineralizer. The products were characterized by X-ray diffractions (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption. The results indicated that the hydrothermal conditions, such as alkaline concentration (n-butylamine), reaction temperature, solvent composition, and the kind of amines, had an important influence on the composition, crystallinity, and morphology of the product. The as-synthesized ZTO samples exhibited high activities and durabilities for photodegradation of methyl orange and the activities were mainly affected by the crystallinities of the samples. A hexagonal-shaped ZTO (H-ZTO) sample was prepared in 0.53M of n-butylamine solution at 180°C for 20h and its optical properties were characterized by UV–Vis diffuse reflectance and Photoluminescence (PL) spectra. Furthermore, the photocatalytic H2 evolution reaction from ethanol aqueous solution over H-ZTO was also investigated. [Copyright &y& Elsevier]

One new type of 3D pillared-layer MOF has been synthesized based on single organic linker with high adsorption capabilities for various hydrocarbon gas and promising CO 2 /CH 4 selectivity. • One new type of 3D pillared-layer framework was prepared by using single indazole-carboxyl liand. • The organic connects metal trimer into 2D layer and further bridges 2D layer resulting in 3D framework. • The unique framework architecture displays high gas adsorption and promising CO 2 /CH 4 selectivity. Herein, by well-designing one bifunctional organic ligand as distinct bridging nodes, one new three-dimensional (3D) pillar-layer MOF, namely as Co 3 (IDCA) 4 (IDCA = 1-H-indazole-5-carboxyle acid), has been synthesized and structurally characterized. The 3D Co 3 (IDCA) 4 framework is composed of linear metal trimer and parazole-carboxyl group with one-dimensional (1D) tetragonal channel. Despite of absence of open metal sites as molecule binding positions, this 3D framework displays promising uptake capacity and separation ability for various hydrocarbon gas molecules. [ABSTRACT FROM AUTHOR]

Die Synthese von Graphenquantenpunkten aus dem industriellen Abfallprodukt Schwarzlauge wird von W. Sun, J. Chen, G. A. Ozin et al. in der Zuschrift auf S. 14992 beschrieben. Die GQDs werden genutzt, um die photokatalytische Aktivität von TiO SB 2 sb in der H SB 2 sb O- und CO SB 2 sb -Reduktion zu steigern. [Extracted from the article]

Supported atomically dispersed metals are proving to be efficacious photocatalysts for CO2 reduction to solar fuels. While being atom efficient, they suffer from being noble, rare, and costly (Pt, Pd, Au, Ag, Rh) and lacking in long‐term stability. Herein, all of these problems are solved with the discovery that atomically dispersed Cu supported on ultrathin TiO2 nanosheets can photocatalytically reduce an aqueous solution of CO2 to CO. The atomically dispersed Cu can be recycled in a straightforward procedure when they become oxidatively deactivated. This advance bodes well for the development of a solar fuels technology founded on abundant, low‐cost, nontoxic, atomically dispersed metal photocatalysts. [ABSTRACT FROM AUTHOR]