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CuO-modified silver bromide (AgBr/CuO) crystal was successful synthesized by a facile method at room temperature. The physical and chemical properties of AgBr/CuO crystals were carefully detected through X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and Electron spin resonance (ESR) techniques. The photocatalytic activity and stability of AgBr/CuO hybrid were evaluated by photocatalytic degradation of methyl orange (MO) under visible light irradiation. The AgBr/CuO sample exhibited high photocatalytic activity, degrading 92% MO after irradiation for 40 min, which was 3.8 times higher than that of pure AgBr. Both the experimental scavenging results and characterization results revealed that O 2 − acts as the main active specie. Based on above, the high photocatalytic performance is mainly attributed to the abundant of oxygen vacancies, and which further generate lots of superoxide radicals. Moreover, the method by using bromide water to rejuvenate AgBr/CuO could well maintain the photocatalytic activity and stability without any environment pollution. [ABSTRACT FROM AUTHOR]

Abstract: Three kinds of AgBr/Ag3PO4 hybrids were synthesised via an anion-exchange precipitation method and characterised by XRD, XPS, SEM, EDS, and UV–vis. The results showed that AgBr/Ag3PO4 hybrids displayed much higher photocatalytic activities than single Ag3PO4 or AgBr under visible light (λ>420nm), and ·OH and h+ were the major active species during the degradation process. Considering interstitial ions on lattice gap of AgBr are easy to become sliver particle, we deduced the possible photocatalytic mechanism could be ascribed to the synergistic effects of the appropriate valence band position of Ag3PO4 and AgBr, surface plasmon resonance effect of Ag0, reactive radical species Br0, and the Ag vacancy on the surface of catalysts. [Copyright &y& Elsevier]

Producing hydrogen from organic/inorganic hydrides is an innovative clean energy alternative to fossil fuels, addressing the increasing energy demands. Here, we first propose coupled photocatalytic water hydrogen production and N,N-dimethylformamide (DMF, C 3 H 7 NO) dehydrogenation technology to obtain high value-added H 2 and N,N-dimethylcarbamic acid (C 3 H 7 NO 2). ZnIn 2 S 4 @MIL-125(Ti) nanoheterostructures were synthesized using a simple solvothermal method and resulting in a photocatalytic H 2 production rate of 2.135 mmol h−1 g−1 (apparent quantum efficiency at 380 nm was 2.6 %) which is 2.77 times higher than pure ZnIn 2 S 4. Liquid-phase mass spectrometry indicates that the DMF oxidation activity of ZIS@MIL heterojunction is double pure ZnIn 2 S 4 and only microcrystalline CO 2 is produced. Isotopes indicate that the production pathway of H 2 results from the coupling of the –CHO bond in DMF and the –H in water. The improved photocatalytic activity of the ZnIn 2 S 4 @MIL-125(Ti) heterostructure is attributed to facilitating efficient charge carrier transfer and separation and DMF depletion of holes accelerates electron transfer. The ZnIn 2 S 4 @MIL-125(Ti) heterojunction was synthesized to enhance the rate of photo-induced charge carrier separation, facilitating the efficient decomposition of dimethylformamide (DMF) for hydrogen production and the generation of valuable intermediate product C 3 H 7 NO 2. [Display omitted] • The ZnIn 2 S 4 @MIL-125(Ti) heterojunction is successfully prepared by two-step hydrothermal method. • The hydrogen production experiment of a new sacrificial agent (DMF). • The photocatalytic products of DMF are analyzed. • The exploration of hydrogen production mechanism are analyzed. [ABSTRACT FROM AUTHOR]

A BiOCl thin film has been successfully synthesized on the Bi plate by a facile method at room temperature. Sodium hypochlorite (NaClO) was used as Cl source, in which Cl − was slow-released through redox reaction of NaClO by ethylene glycol (EG). The X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflection spectrometry (DRS) were employed to characterize the structure, morphology, and optical property of the as-prepared BiOCl thin film. The photocatalytic activity and stability of BiOCl thin film was evaluated by degradation of rhodamine B under both simulated solar light and visible light. The results indicated that as-prepared BiOCl thin film had excellent catalytic efficiency and good cycling performance towards photodegradation of RhB. Furthermore, a possible formation mechanism of BiOCl thin film on Bi plate had been proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] Performance of single-atom catalysis largely depends on the interaction between the metal and the supporter. Herein, ethylene glycol (EG) was used as a molecular bridge connecting Palladium (Pd) and bismuth oxybromide (BiOBr) to form atomically dispersed Pd catalyst (Pd-EG-BiOBr) for photocatalytic nitrogen fixation under ambient conditions. Compared with 0.20 wt% Pd-BiOBr, 0.20 wt% Pd-EG-BiOBr greatly promoted the photocatalytic nitrogen fixation activity, affording an ammonia formation rate of 124.63 μmol·h−1. The molecular bridge mechanism during catalyst formation and photocatalysis is speculated based on Transmission electron microscopy, In-situ Fourier transform infrared spectra, Electron spin resonance spectra, UV–vis diffuse reflectance spectra, Photoluminescence spectra and Density Functional Theory calculations. The results show that EG not only induces the formation of atomically dispersed Pd, but also enhances the electron density of Pd and activation capacity of nitrogen molecules. This work opens a new door to applications of atomically dispersed Pd supported catalysts for high efficiency photocatalytic nitrogen fixation. [ABSTRACT FROM AUTHOR]

Abstract A novel TiO 2-x /Ag 3 PO 4 composite photocatalyst with controllable oxygen vacancies (V o ·) amount was designedly prepared to avoid the photocorrosion and promote reduction capacity of Ag 3 PO 4 photocatalyst. The V o · on TiO 2-x work as molecular oxygen activation center trapping electron and O 2 to form ·O 2 -, and then avoided the electrons combine with h+ and/or Ag+. Compared with Ag 3 PO 4 , TiO 2-x , and TiO 2 /Ag 3 PO 4 , TiO 2-x /Ag 3 PO 4 showed obviously efficient visible light and natural indoor weak light photocatalytic activity and stability for the photodegradation of Bisphenol A (BPA). The photoelectric conversion spectra, Ag 3d XPS narrow scan spectra, ESR DMPO-·O 2 - species spectra revealed that the TiO 2-x /Ag 3 PO 4 had a higher photocurrent density, lower photocorrosion and more generation of superoxide radical than those of Ag 3 PO 4. Interestingly, compare with single h+ degradation pathway over Ag 3 PO 4 , the h+ and ·O 2 - synergistic degradation pathway over TiO 2-x /Ag 3 PO 4 is more beneficial to the BPA degradation. This work highlights the relations between the photocatalyst structure, active species and pollutant degradation pathway. [ABSTRACT FROM AUTHOR]

Band-gap regulation of photocatalysts has been turned out to be a very important approach to achieve high effective utilization of solar spectrum and obtain an optimal photocatalytic property. Herein, a novel iodide modified Bi 4 O 5 Br 2 photocatalyst with controlled band-gap position was successfully synthesized for the first time via a simple alcoholysis-hydrolysis method at room temperature. The band structure, optical absorption properties, photo-induced charges transfer/separation rate of the synthesized samples were characterized by UV-vis DRS, Mott-Schottky method, valence band (VB) XPS, electrochemical impedance spectra and photoelectric conversion spectra. The results demonstrated that the conduction band position of Bi 4 O 5 Br 2 continuously decreased from 2.46 eV to 2.16 eV, and then the visible-light response and photo-generated carrier separation changes took place. Owing to the higher visible-light absorption capacity, lower interfacial charge-transfer resistance, and more efficient separation of the photoinduced charges, the iodide modified Bi 4 O 5 Br 2 exhibited a higher visible-light activity than pure Bi 4 O 5 Br 2 for the photocatalytic degradation of Bisphenol A (BPA) and NO removal under visible light irradiation. Ultimately, the repeated photodegradation experiments of BPA displayed that the obtained sample is stable and resistant to chemical or photochemical corrosion. We believe such a simple and effective strategy could pave a new way for narrowing continuously the band gap of an existed photocatalyst to control the generation and recombination rate of photo-induced carriers. [ABSTRACT FROM AUTHOR]

A metastable hexagonal WO 3 (h-WO 3 ) was prepared by a hydrothermal reduction method with glycerol and the Ag 3 PO 4 /h-WO 3 composites were synthesized via a precipitation method. Several techniques were employed to characterize the Ag 3 PO 4 /h-WO 3 composites. Compared to the Ag 3 PO 4 /WO 3 photocatalysts, the Ag 3 PO 4 /h-WO 3 photocatalysts exhibited an excellent visible light photocatalytic performance for efficient degradation of methyl orange (MO). The analysis results showed that the favorable photocatalytic performance of the Ag 3 PO 4 /h-WO 3 composites were mainly attributed to the h + and O 2 − generated during the recycles of W 6+ and W 5+ . Furthermore, under the same conditions, the Ag 3 PO 4 /h-WO 3 composites showed better stability than pure Ag 3 PO 4 photocatalyst for degradation of MO, indicating that h-WO 3 played an important role in the process of degradation. Based on the results of trapping experiments and XPS characterization analysis, the photocatalytic mechanism of the Ag 3 PO 4 /h-WO 3 composites were proposed. [ABSTRACT FROM AUTHOR]

An Ag@AgCl/Ag nanofilm/ZIF-8 composite photocatalyst was successfully constructed for the first time by loading Ag@AgCl and Ag nanofilm on the surface of ZIF-8 simultaneously via a simple deposition-photoreduction method. The formed Ag nanofilm was harnessed as a mediator to transfer photo-induced electrons from the plasmonic Ag@AgCl nanostructure to ZIF-8 for enhancing the photocatalytic reaction rate with visible light. The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue (MB) under visible light irradiation. The first-order kinetic constant of MB degradation over Ag@AgCl/Ag nanofilm/ZIF-8 (14.762 h −1 ) was nearly 2 times of Ag@AgCl/ZIF-8 (7.932 h −1 ). The electrochemical impedance spectra, photoelectric conversion spectra and ESR DMPO-O 2 − species spectra revealed that AFZ had a lower resistance, higher photocurrent density and more generation of superoxide radical than those of AZ, meaning that the extended interface between Ag nanofilm and ZIF-8 could promote the quick electrons transfer and electron-hole pairs separation. This work provides a new type electrons transfer mediator in fabrication of efficient plasmonic photocatalysts. [ABSTRACT FROM AUTHOR]

The novel BiPO 4 /BiOCl heterojunction composites were successfully fabricated by a facile one-step hydrothermal method. The XRD, SEM, TEM, UV–vis DRS, transient photocurrent and EIS measurements were employed to characterize the phase structures, morphologies, optical properties, and electron–hole separation effect of the photocatalysts. BiPO 4 /BiOCl composites exhibited much higher photocatalytic activity for the methyl orange (MO) degradation than single BiOCl and BiPO 4 under simulated sunlight irradiation. Moreover, the stability test for the optimum synergetic molar ratio of BiPO 4 /BiOCl composites indicated that the synthetic p-n heterojunction BiPO 4 /BiOCl photocatalyst had the gratifying reutilization after five cycles. The results of transient photocurrent measurements and EIS demonstrated that the large enhancement of photocatalytic activity could be mainly ascribed to the surface junction of BiPO 4 /BiOCl composite which can effectively improve electron-hole separation speed during photocatalytic process. [ABSTRACT FROM AUTHOR]

The rutile TiO 2 /BiOCl composites were successfully fabricated by a facile one-step hydrolysis method at low temperature (50 °C). The X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectra, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and X-ray photoelectron spectroscopy measurements were employed to characterize the phase structures, morphologies, optical properties, surface areas, and electronic state of the samples. The rutile TiO 2 /BiOCl composites exhibited higher photocatalytic activity than pure BiOCl and rutile TiO 2 for the degradation of phenol under artificial solar light irradiation. In addition, the photocatalytic mechanism has also been investigated and discussed. The enhanced photocatalytic performance of rutile TiO 2 /BiOCl composites is closely related to the heterojunctions between BiOCl and rutile TiO 2 , which can not only broaden the light adsorption range of BiOCl but also improve the electron–hole separation efficiency under artificial solar light irradiation. [ABSTRACT FROM AUTHOR]

The bottlenecks of photocatalytic nitrogen fixation are adsorption and activation of nitrogen, because N–N bond in dinitrogen is one of the strongest bonds in chemistry. Herein, for the first time, Cu-doped MIL-101(Fe) was applications in photocatalytic nitrogen fixation. The photocatalytic nitrogen fixation activity of Cu-MIL-101(Fe) is three times that of MIL-101(Fe). Characteristic of MIL-101(Fe) and Cu-MIL-101(Fe) are systematically compared by XRD, SEM, TEM, BET, PL and energy band structure. These results indicated that the Cu doping not only enlarge the specific surface area from 1413 ​m2/g to 2097 ​m2/g, but also increase the photoreduction capability from −0.13 ​V to −0.7 ​V. These results indicated that nitrogen adsorption and activation capacity can be improved by Cu doping. By combining metal ions doping and components regulation of MOFs, this work provides many future opportunities for enhance photocatalytic nitrogen fixation activity. [Display omitted] • Cu doped MIL-101(Fe) was synthesis by a solvent thermal method. • Cu-MIL-101(Fe) displays superior photocatalytic activity and stability. • Cu doping improve specific surface area and photoreduction capability. • The enhanced photocatalytic activity attribute to the increased nitrogen adsorption and activation capacity. [ABSTRACT FROM AUTHOR]

Abstract: A series of micro-nano-structure BiOBr thin films were prepared at a low temperature by the alcoholysis-coating method using BiBr3 as precursor. The as-prepared films were characterized by X-ray powder diffraction, scanning electron microscopy, and Brunauer–Emmett–Teller surface area. The obtained results indicated that micro-nano-structure tetragonal BiOBr films with different intensity ratios of (110) to (102) characteristic peaks could be synthesized through controlling the reaction temperature and the calcination temperatures. Furthermore, the photocatalytic activities of BiOBr thin films with different preparation conditions have been evaluated by the degradation of methyl orange (MO) under UV light irradiation, suggesting that the photocatalytic activity should be closely related to the solvent, the alcoholysis reaction temperature, and the calcining temperature. The best photocatalytic degradation efficiency of MO for BiOBr thin films reaches 98.5% under 2.5h UV irradiation. The BiOBr thin films display excellent stability and their photocatalytic activity still remains above 90% after being used five times. The main reasons for the higher photocatalytic activity of micro-nano-structure BiOBr microspheres have been investigated. In addition, the possible formation mechanism of BiOBr thin films with micro-nano-structure and excellent photocatalytic activity was proposed and discussed. [Copyright &y& Elsevier]

Two kinds of layer-structured BiOCl photocatalysts (BiOCl-01 and BiOCl-02) were synthesized using NaBiO3 and HCl as the raw materials, and KCl as the Cl− conditioning agent. These photocatalysts were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and ultraviolet visible diffuse reflectance spectra (DRS) measurements. The effects of chlorine ion in the reaction solutions on the crystalline of BiOCl and photodegradation of Rhodamine B (RhB) under 365 nm and 530 nm monocharomatic light irradiation were investigated. The XRD spectra confirmed the formation and purity of BiOCl photocatalysts, revealed that Cl− ion existed in the preparation solution restrained the growth of BiOCl and influenced the surface configuration. The TEM and HRTEM analysis gave the similar results with XRD. The band gaps of BiOCl-01 and BiOCl-02 were estimated about 3.19 and 3.29 eV, respectively. The photocatalytic degradation results of RhB under 365 nm showed that the photocatalytic activity of BiOCl-02 was better than that of BiOCl-01, and the main active species were h+ and [ABSTRACT FROM AUTHOR]

Abstract: In order to provide fundamental understanding and guidance for the effective Mn doping BiOCl and enhanced physicochemical properties derived from the interplay between Mn dopant and oxygen defect, the density functional theory (DFT)+U calculations were adopted to evaluate the effects of Mn doping and oxygen vacancy defects on the geometric structure, electronic property, optical absorption, Mulliken charge and effective mass of BiOCl. The suitable theoretical models were built up and their relaxed structural parameters agree well with the experiment values. It is found that both substitutional and interstitial Mn doping BiOCl not only are energetically favorable but also modify band structures to achieve remarkable optical red-shift of BiOCl, and the substitutional Mn-doped BiOCl show better feasible Mn doping behavior due to the beneficial p-type doping characteristic and p–d hybridization between substitutional Mn and adjacent Bi (or O) atoms in the CB (or VBM). The occurrence of oxygen vacancy in BiOCl crystal significantly influences the neighboring Bi 6p states, forming a capture center of photo-excited electrons in the forbidden band, which enhances the efficient mobility of photo-generated carriers and improves the effective separation rate of electron–hole pairs. The better negative formation energy of substitutional Mn-doped BiOCl with oxygen vacancy (BiOCl:V O) demonstrates thermodynamically its favorable structural stability. Besides, the higher relative ratio value for the effective masses of activated holes and electrons in the Mn-doped BiOCl:V O system implies the lower recombination rate of electron–hole pairs. Furthermore, our calculated optical absorption spectra exhibit that the spectral absorption edge of BiOCl is obviously red-shifted and extends to visible, red and infrared light region by the synergistic effect of oxygen vacancy and Mn dopant. Therefore, we theoretically predicted that Mn-doped BiOCl:V O system is expected to become highly promising semiconductor material applied in photocatalytic field for effectively photochemical decomposition of organics or water splitting under the sunlight irradiation. [Copyright &y& Elsevier]

Abstract: In this study, a novel BiOCl thin film with flakelike structures has been successfully prepared through electrochemical method composed of a cathodic electrodeposition and an anodic oxidation at room temperature. The samples obtained at the different oxidation voltages were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), electronic energy spectrum (EDS), and UV–vis diffuse reflectance spectra (UV–vis DRS). The analysis results show that the morphological, structural, and optical characteristics of BiOCl thin films depend markedly on the anode oxidation voltage and the lattice orientation of BiOCl thin film is transformed mainly into (110) surface with the increasing oxidation voltages. The observed results of high-resolution transmission electron microscopy (HRTEM) confirm that pure tetragonal BiOCl thin film with the highly exposed (110) surface is obtained at 2.0V and consists of interlaced nanosheets. First-principles calculations reveal that the existence of BiOCl (110) surface states enhances the electron transition and efficient separation of photo-induced electron–hole pairs. The optimized BiOCl thin film can not only guarantee the intrinsic photochemical properties of BiOCl bulk but also exhibit additional electronic characteristics of BiOCl (110) surface, and consequently the wonderful synergistic effect between BiOCl bulk and BiOCl (110) surface accelerates the efficient separation of electron–hole pairs and produces the high reducing superoxide radicals O2 − ng oxidizing hydroxyl radicals ed for the degradation of organic compounds. For as-prepared BiOCl thin film, the degradation ratio of methyl orange (MO) reaches 98% under 2.5h UV irradiation at the first cycle and still remains 90% at the fifth cycle, and the COD removal efficiency of 50mg/L MO solution over BiOCl thin film achieves 73.47% after 8h reaction time. The BiOCl thin film with highly exposed {110} facets exhibits the excellent photocatalytic performance and potential application in photocatalysis field. [Copyright &y& Elsevier]

Photocatalytic reaction mechanism of SMZ degradation over PtO/Pt4+-BiOCl. • A novel defects-filled strategy was exploited by filling Pt4+ into Bi defects of BiOCl. • PtO/Pt4+-BiOCl displays superior photocatalytic activity and stability. • Pt4+ inside the lattice of BiOCl increasing the light absorption capacity. • The defects-filled mechanism was confirmed. Photocatalyst performance largely depends on the arrangement of surface atoms, especially nanomaterials. Herein, we proposed a novel defect-filled strategy by filling Bi defects on BiOCl surface with Pt4+ to achieve the controlled arrangement of BiOCl-surface atoms. The resulting PtO/Pt4+-BiOCl photocatalyst showed higher sulfamethoxazole (SMZ) degradation and photocatalytic nitrogen-fixation efficiency than PtO/BiOCl. The first-order kinetic constant of SMZ degradation over PtO/Pt4+-BiOCl (0.1312 min−1) was nearly twofold higher than that of PtO/BiOCl (0.0776 min−1). The photocatalytic nitrogen fixation activities of PtO/BiOCl and PtO/Pt4+-BiOCl were 244.2 mol·L−1·h−1 and 375.6 mol·L−1·h−1, respectively. The enhanced photocatalytic activity mainly attributed to the increased light absorption ability and separation efficiency of electron-hole pairs by Pt4+ doping. The defect-filled mechanism was confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Electron spin resonance (ESR), and Positron annihilation spectrometry. All these results indicated that the electrostatic interaction between Pt4+ in the precursor and Bi defects on the BiOCl surface was the key step in the defect-filled process. This work provides a new strategy for controlling the surface atom arrangement of nanomaterials. [ABSTRACT FROM AUTHOR]

Novel Bi 4 Ti 3 O 12 hollow-spheres (BTO-HS) with self-assembly structured nanosheets are successfully synthesized by simple hydrothermal-treatment process for the first time, and exhibit excellent photocatalytic CO 2 reduction activity to CO under simulated sunlight irradiation. • Novel Bi 4 Ti 3 O 12 hollow-spheres (BTO-HS) are successfully synthesized. • Hydrothermal-treatment process regulates the formation of hollow-spheres. • BTO-HS shows excellent CO 2 photoreduction activity to CO (104.64 μmol⋅g−1). • Possible photocatalytic CO 2 reduction mechanism of BTO-HS is proposed. • Newfangled structural regulation strategy for prominent BTO-based photocatalysts. The utilization of artificial photosynthesis technology to achieve CO 2 green conversion to solar fuels has attracted great attentions. However, the research and development of highly-efficient photocatalytic materials have been the key scientific issues. In this work, novel Bi 4 Ti 3 O 12 hollow-spheres (BTO-HS) with self-assembly structured nanosheets are successfully synthesized by simple hydrothermal-treatment process for the first time, and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectroscopy (DRS). The unique structural morphology and well-matched oxidation–reduction potentials of as-prepared BTO-HS result in the excellent optical responsiveness and effective photoinduced carriers, achieving the highly-efficient CO 2 photoreduction activity with CO yield of 13.1 μmol⋅g−1⋅h−1 (8 h), more than ultramodern reported 11.7 μmol⋅g−1⋅h−1 (4 h) of ultrathin BTO nanosheets with OVs and 3.66 μmol⋅g−1⋅h−1 (4 h) of bulk BTO https://doi.org/10.1016/j.scib.2020.02.019 under simulated sunlight irradiation. More importantly, the CO yield only decreases about 3.8% after third-cycle test, indicating the outstanding active stability of BTO-HS. Our findings should provide a newfangled structural regulation strategy for constructing BTO-based photocatalysts with highly-efficient photocatalytic CO 2 reduction performance. [ABSTRACT FROM AUTHOR]