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Graphite carbon nitride (g-C3N4) is a promising photocatalyst for its high catalytic activity, low-cost and high-biosafety characteristics. Due to the complexity of underwater photochemical reaction conditions and the disadvantages of g-C3N4 itself such as low specific surface area, easy recombination of photogenerated electron–hole pairs and insufficient light absorption capacity, the application of g-C3N4 in the field of water purification is limited. For improving underwater photocatalytic performance of g-C3N4, a g-C3N4/carbon nanotubes (CNT-CN) composite photocatalyst with high specific surface area and enhanced light absorption capacity were prepared by in situ solvothermal method. Its photodegradation efficiency at different underwater transmission light was further studied. The results show that CNT has good compatibility with g-C3N4. g-C3N4 can grow in situ on the surface of CNT and form a stable composite structure. Moreover, its degradation efficiency under long-wavelength irradiation is improved significantly. The degradation rate of CNT-CN at 550-700 nm was about 3 times than that of g-C3N4. Furthermore, CNT-CN can maintain higher photocatalytic activity under water. At 40 cm depth where light intensity and ultraviolet spectra were attenuated 63.8% and 80.1%, respectively, the degradation rate of CNT-CN3 can still reach 3.49 times than that of g-C3N4. Based on this study, the introduction of CNT effectively promotes the electron–hole separation efficiency of g-C3N4, widens its spectral response range, and thus improves its underwater degradation efficiency. [ABSTRACT FROM AUTHOR]

Surface acid site regulation of photocatalysts is a promising strategy to improve their performance. Herein, surface acid sites of cadmium sulfide were rationally regulated by cerium doping, which resulted in significantly increased photocatalytic activity for tetracycline hydrochloride (TC-HCl) degradation. The generated Brønsted acid sites were verified to favor the adsorption of organic molecules because of their strong affinity. Meanwhile, Lewis acid sites acted as the active sites for C–C bond cleavage via a nucleophilic substitution process, which was testified by the Fukui function and electrostatic potential. Besides, Ce3+ doping suppressed the recombination of electron–hole pairs, which also boosted the performance of TC-HCl degradation. Moreover, the degradation pathway of TC-HCl was deduced based on theoretical calculations and HPLC-MS results. The toxicity of pollutants and intermediates was also evaluated. This work provided new insight into the rational design and preparation of highly efficient photocatalysts for environmental purification. [ABSTRACT FROM AUTHOR]

Polymeric carbon nitride (PCN) as a class of two‐electron oxygen reduction reaction (2 e− ORR) photocatalyst has attracted much attention for H2O2 production. However, the low activity and inferior selectivity of 2 e− ORR greatly restrict the H2O2 production efficiency. Herein, we develop a new strategy to synthesize hydrophilic, fragmented PCN photocatalyst by the terminating polymerization (TP‐PCN) effect of iodide ions. The obtained TP‐PCN with abundant edge active sites (AEASs), which can form quasi‐homogeneous photocatalytic system, exhibits superior H2O2 generation rate (3265.4 μM h−1), far surpassing PCN and other PCN‐based photocatalysts. DFT calculations further indicate that TP‐PCN is more favorable for electron transiting from β spin‐orbital to the π* orbitals of O2, which optimizes O2 activation and reduces the energy barrier of H2O2 formation. This work provides a new concept for designing functional photocatalysts and understanding the mechanism of O2 activation in ORR for H2O2 production. [ABSTRACT FROM AUTHOR]

Considerable efforts have been directed towards constructing high-efficiency, earth-abundant and low-cost photocatalysts for hydrogen evolution under visible light irradiation. In this work, 2D ultrathin CoP-decorated bimetallic MnxCd1−xS photocatalysts were developed based on the combined strategies of controllable band structure and co-catalyst modification. An optimal H2 production rate of 65 324 μmol g−1 h−1 was obtained for the Mn0.5Cd0.5S/CoP-4% sample under visible light irradiation, which was 4.26 times higher than that of pure Mn0.5Cd0.5S as well as 38.7 times that of pure CdS. UV-vis and MS characterization results showed that the introduction of Mn into CdS could change the band potential towards a more negative direction, which would be beneficial for water reduction. Moreover, the added CoP could act as a co-catalyst to facilitate the electron transfer and restrain the recombination of photogenerated electron–hole pairs, which was testified by photocurrent, PL and EIS analyses. This work paves the way to offer a new direction towards designing efficient photocatalysts for hydrogen evolution. [ABSTRACT FROM AUTHOR]

Abstract Photocatalytic water splitting has aroused great interest as a clean and renewable energy conversion process. In this study, we prepared a novel noble-metal-free multiple heterojunction photocatalyst (CdS@C-CoP) composed of CdS nanorods, conducting carbon layer and CoP nanoparticles cocatalyst for the first time. The obtained CdS@C-CoP composites exhibited excellent performance and stability under visible light irradiation when it was used as photocatalysts for hydrogen evolution. For the optimum CdS@C-CoP sample, an average hydrogen evolution rate reached up to 10089 μmol g−1 h−1, nearly 6 fold as high as that of pure CdS. The enhanced photocatalytic hydrogen production rate can be ascribed to the synergistic effect between conductive carbon layer and surface cocatalyst CoP, which resulted in efficient separation of photoexcited charge carriers and abundant active sites for hydrogen reduction. This work presented a novel way to design composite photocatalyst with efficient hydrogen generation properties through combining two kinds of surface modification methods: thin carbon layer coating and surface cocatalysts loading. Highlights • Well-designed CdS@C-CoP composite is designed for the first time. • Greatly enhanced photocatalytic hydrogen evolution rate and stability under visible light irradiation. • Synergism between carbon layer and CoP is beneficial for the CdS nanorods to achieve high hydrogen evolution performance. [ABSTRACT FROM AUTHOR]

Atrazine, a typical herbicide, has caused extensive concern due to its wide application and persistance. In this work, a visible light responsive photocatalyst BiOBr/UiO-66 was synthesized and applied to the degradation of atrazine. The BiOBr/UiO-66 materials exhibited significantly enhanced photocatalytic performance on the degradation of atrazine under visible light irradiation compared to pure BiOBr. Moreover, the effects of typical environment factors (i.e. pH, common anions, inorganic cations and water matrix) on the degradation of atrazine were investigated extensively. Results showed that atrazine was degraded with the fastest rate at the strong acidity conditions of pH = 3.1 in the investigated pH region (3.1–9.4). The photocatalytic degradation of atrazine was obviously inhibited by HCO 3 − and SO 4 2− . However, Cl − had negligible influence on the degradation of atrazine. Inorganic cations had little influence on the degradation of atrazine. Futhermore, the water matrix showed apparent impacts on the photocatalytic degradation of atrazine by BiOBr/UiO-66. In mineral water, tap water and river water, the removal efficiency of atrazine was evidently lower than that in pure water. The main active species that responsible for the degradation of atrazine by BiOBr/UiO-66 were determined to be ·O 2 − and h + . Ultimately, the degradation pathways of atrazine were proposed based on the intermediates detected by LC-MS/MS. [ABSTRACT FROM AUTHOR]

In this work, flower-like Au/Bi 2 O 2 CO 3 /Bi 2 O 3 multi-heterojunction photocatalysts were prepared by a in-situ growth method. The as-prepared samples were characterized by different techniques including Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), UV–vis diffuse reflectance spectrometry (DRS), X-ray photoelectron spectroscopy (XPS), Photoluminescence (PL) and photo-induced current. The photocatalytic performance of the as prepared samples was evaluated by degradation of rhodamine B (RhB) under visible light (λ > 400 nm). Au/Bi 2 O 2 CO 3 /Bi 2 O 3 exhibited much higher activity than pure Bi 2 O 2 CO 3 or Bi 2 O 2 CO 3 /Bi 2 O 3 . The rate constant of best one Au/Bi 2 O 2 CO 3 /Bi 2 O 3 sample is 100 and 14 times as that of pure Bi 2 O 2 CO 3 and β-Bi 2 O 3 /Bi 2 O 2 CO 3 , respectively. The enhanced photocatalytic activity of Au/Bi 2 O 2 CO 3 /Bi 2 O 3 can be ascribed to the surface plasmon resonance (SPR) effects of Au nanoparticles and the formed multi-heterojunctions, which enhanced the absorbance of visible light and facilitated the transferring and separation of photogenerated electron-hole pairs, respectively. [ABSTRACT FROM AUTHOR]

A series of BiOCl-Ag 3 VO 4 heterojunction photocatalysts with high visible light photocatalytic activity were synthesized by a in-situ growth route. The obtained samples were characterized by X-ray diffraction spectroscopy, UV-vis diffuse reflectance spectra, field emission scanning electron microscopy and transmission electron microscopy. The azo dye reactive brilliant red X-3B was chosen as the target pollutant to investigate the photocatalytic activity of the as-prepared heterojunctions under visible light irradiation. The BiOCl-Ag 3 VO 4 composite photocatalysts exhibited much higher photocatalytic efficiency than pure BiOCl. The photoluminescence spectra and photocurrent results indicated that the enhanced activity was ascribed to the efficient charge separation and transfer between BiOCl-Ag 3 VO 4 heterojunction. Furthermore, it was found that the content of Ag 3 VO 4 affected the photocatalytic activity apparently. The highest activity was obtained with mole ratio of 2% for Ag 3 VO 4 in the present work. Besides, a possible mechanism of enhanced photocatalytic activity was proposed for the degradation of dye under visible light. [ABSTRACT FROM AUTHOR]

In this study, BiOBr–titanium phosphate (BiOBr/TP) plate-on-plate composites with p–n heterojunctions were synthesized using a simple, feasible two-step method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and UV-vis diffuse reflectance spectrometry (DRS) were used to evaluate the structure, morphology and optical properties of the composites. Rhodamine B (RhB) and ciprofloxacin (CIP) were chosen as model pollutants to evaluate the photocatalytic activity of the synthesized samples under irradiation of both ultraviolet and visible light. The BiOBr/TP composites exhibited much higher photocatalytic activity for the degradation of both pollutants than pure TP. The enhanced photocatalytic performance can be ascribed to the formed p–n heterojunctions between p-type BiOBr and n-type TP, which efficiently reduced the recombination rate of photo-excited electrons and holes. Moreover, a possible photocatalytic mechanism of organic pollutant degradation by the obtained samples was presented in detail. [ABSTRACT FROM AUTHOR]

In this paper, novel p–n type heterojunction BiOI/La2Ti2O7 nanocomposites were synthesized via a simple method for obtaining visible light activated photocatalysts. The crystal phases and crystallinity of the prepared samples were analyzed by X-ray diffraction (XRD). The morphologies of the BiOI/La2Ti2O7 composites were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The elemental composition and states were analyzed by X-ray photoelectron spectroscopy (XPS). Results showed that the obtained composites were constructed by 2D BiOI and La2Ti2O7 nanosheets. Besides, UV-vis diffuse reflectance spectrometry (DRS) indicated that BiOI/La2Ti2O7 composites possessed better visible light absorptive properties than pure La2Ti2O7. The photocatalytic activity was evaluated by the degradation of Rhodamine B (RhB), dye X-3B, methyl orange (MO) and a colorless antibiotic agent, ciprofloxacin (CIP), under visible light irradiation. Results showed that BiOI/La2Ti2O7 composites exhibited much higher activity than the corresponding single components. First of all, the enhanced activity can be ascribed to the improved visible light harvesting. Secondly, the results of photo-induced current and photoluminescence spectroscopy illustrated that the enhanced performance can also be attributed to the efficient transfer and separation of photoinduced charges, which resulted from the formed p–n heterojunctions between BiOI and La2Ti2O7. It can be expected that this novel 2D–2D p–n heterostructured photocatalyst would be a promising candidate for environmental remediation. [ABSTRACT FROM AUTHOR]

In this study, magnetic graphene oxide-loaded Ce-doped titania (MGO–Ce–TiO 2 ) hybridized composite was prepared by a facile method. The as-prepared samples exhibited good adsorption capacity, high visible-light photoactive and magnetic separability as a novel photocatalyst in the degradation of tetracyclines (TC). The intermediate products and photocatalytic route of TC were proposed based on the analysis results of LC–MS. Moreover, the repeatability of the photoactivity with the use of MGO–Ce–TiO 2 was investigated in the multi-round experiments with the assistance of an applied magnetic field. Therefore, the prepared composite photocatalysts were considered as a kind of promising photocatalyst in a suspension reaction system, in which they can offer effectively recovery ability. The effect of MGO content on the photocatalytic performance was also studied, and an optimum content was obtained. [ABSTRACT FROM AUTHOR]

AgBr/Ag 2 CO 3 heterojunctions were synthesized via a simple one-pot co-precipitation process. Namely, the growth of Ag 2 CO 3 and AgBr crystals occurred simultaneously in one single process. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of as-prepared samples was investigated by degradation of Rhodamine B (RhB) under visible light irradiation. An enhancement in photocatalytic activity was observed in AgBr/Ag 2 CO 3 composites compared with pure AgBr and Ag 2 CO 3 . We also investigated the effect of the ratio of AgBr/Ag 2 CO 3 on the photocatalytic activity of the as-prepared heterojunctions. With the optimal theoretical Br − / CO 3 2 - molar ratio of 1:2, the sample exhibits the highest photocatalytic activity. [ABSTRACT FROM AUTHOR]

Hydrogen evolution by photocatalytic water splitting has attracted extensive attention in recent years. Here we report a composite photocatalyst, in which graphene and Pt particles act as cocatalysts to modify CdS nanowires. This composite photocatalyst was prepared by a solvothermal method followed by a photoreduction process. The obtained samples were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence and Brunauer–Emmett–Teller specific surface area analysis. The graphene and Pt comodified CdS nanowires gain a high hydrogen evolution rate of 3984 μmol h−1 g−1, which is almost 4 times higher than that of bare CdS nanowires and also higher than the sum of graphene–CdS and Pt–CdS nanowires. The obtained sample also exhibits a good stability. The encouraging results presented here can be attributed to the incorporation of graphene and Pt which show a synergetic effect for hydrogen evolution. This work paves a way to the potential application of CdS nanowires in energy conversion. [ABSTRACT FROM AUTHOR]

In this work, a series of novel flower-like Bi2O2CO3/CdS heterojunctions were prepared by a simple and feasible two-step process. The phase structures of as-prepared samples were examined by X-ray diffraction (XRD). Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) were used to confirm the flower-like heterostructures of the Bi2O2CO3/CdS composites. The Brunauer–Emmett–Teller (BET) specific surface area (SBET) of samples were analyzed by N2 adsorption–desorption isotherms. UV-vis diffuse reflectance spectrometry (DRS) revealed that Bi2O2CO3/CdS heterojunctions exhibited better light absorptive properties than pure Bi2O2CO3. The photocatalytic activity was investigated by the degradation of MB under visible light irradiation. The results showed that the as-prepared Bi2O2CO3/CdS heterojunctions exhibited much higher activity than pure Bi2O2CO3. The photoluminescence (PL) spectra and photocurrent studies indicated that the recombination of photogenerated electron–hole pairs was decreased effectively due to the formation of heterojunctions between flower-like Bi2O2CO3 and CdS nanoparticles. Trapping experiments indicated that ṖO2− radicals were the main reactive species for MB degradation in the present photocatalytic system. Furthermore, the cycling experiments revealed the good stability of Bi2O2CO3–CdS composites. [ABSTRACT FROM AUTHOR]

A magnetically separable graphene–TiO 2 (MG–TiO 2 ) hybrid photocatalyst was successfully prepared by a one step method. Namely, simultaneous reduction of graphene oxide and deposition of TiO 2 on the graphene was occurred in one single process. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) analysis, X-ray photoelectron spectroscopy (XPS) and The Brunauer–Emmett–Teller (BET) analysis. The photocatalytic activity of the obtained samples was measured by the decomposition of methylene blue (MB) and tetrabromobisphenol A (TBBPA, a brominated flame retardant) under UV light irradiation. The results showed that MG–TiO 2 exhibited much higher photocatalytic performance than that of bare TiO 2 . The enhanced activity can be ascribed to the incorporation of graphene. In addition, the MG–TiO 2 with MG content of 3% exhibited the highest activity towards MB and TBBPA degradation. The intermediates of TBBPA in the photocatalytic degradation process were analyzed by LC–MS. On the basis of the identified intermediates, the photocatalytic degradation pathway of TBBPA was proposed. Furthermore, the recyclable ability of the samples was also studied and the results showed that the samples exhibited high stability. [ABSTRACT FROM AUTHOR]

Abstract: Magnetic graphene oxide–Ag3PO4 (MGO–Ag3PO4) nanocomposites were prepared by a facile method, and used as photocatalysts for the degradation of methylene blue (MB) in water under visible light irradiation. The MGO–Ag3PO4 hybrids were characterized by X-ray diffraction spectroscopy, field emission scanning electron microscopy and UV–vis diffuse reflectance spectra. The results indicated that the as-prepared samples exhibited an enhanced photoactivity toward MB degradation compared to bare Ag3PO4. Further study showed that the dominate radicals was the photogenerated holes in the degradation process of MB. GO can suppress the recombination of electron–hole pairs, and improve the photocatalytic performance. Furthermore, the composites can be separated easily by an external magnet. At the same time, the MGO–Ag3PO4 composite exhibited higher stability compared to Ag3PO4. [Copyright &y& Elsevier]

Ag/AgCl@chiral TiO2 nanofibers are synthesized to tune the angle of the incident visible light through the chiral structure of the TiO2 nanofibers, intensifying the surface plasmon resonance effect of the supported Ag/AgCl materials, which are proven to be a highly active and stable visible light photocatalyst for the degradation of 17-β-ethinylestradiol. [ABSTRACT FROM AUTHOR]

Abstract: Graphene modified titania nanorod arrays composite films were prepared by a simple solvothermal method. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photo-induced current and electrochemical impedance spectroscopy (EIS). The photocatalytic activity was investigated by the degradation of methylene blue (MB) under UV light. An increase in photocatalytic activity was observed for the composite photocatalysts compared with pure one. This improvement was attributed to the increased migration efficiency of photo-induced electrons. Furthermore, the effect of graphene content on the photocatalytic activity was also investigated. Results showed that the sample prepared with initial graphene oxide concentration of 0.1mgmL−1 exhibited the highest photocatalytic activity for MB degradation. [Copyright &y& Elsevier]

Photocatalytic hydrogen production via conversion of solar energy shows great potential in addressing both environmental contamination and energy shortage. In the present study, a new CdS–NiS/SnO 2 photocatalyst was designed based on the strategies of enhancing the efficiency of water dissociation and electron transfer/separation. A prominent H 2 generation rate of 35,176 μmol g−1 h−1 (λ ≥ 420 nm) was obtained for the optimal sample, which was 12.8 and 6 times as that of CdS and CdS/SnO 2 , respectively. The significantly high performance of CdS–NiS-10%/SnO 2 could primarily be attributed to the synergistic effect of the improved efficiency of charge transfer, H 2 O adsorption and dissociation. Fourier transform infrared (FT-IR) demonstrated that NiS can increase the adsorption of H 2 O molecules. Further, pursuant to linear sweep voltammetry (LSV), Tafel and photoluminescence (PL) results, a faster kinetics process of water dissociation could be obtained through the addition of SnO 2. Meanwhile, electrochemical impedance spectroscopy (EIS), photocurrent characterizations revealed that CdS–NiS-10%/SnO 2 exhibited faster charge transfer efficiency. This work is hoped to offer a new approach/concept in researching CdS-based photocatalysts with enhanced hydrogen generation activity under the irradiation of visible light. • CdS–NiS/SnO 2 composites showed excellent photocatalytic hydrogen evolution rate. • SnO 2 has a superior conductivity that could enhance electrons transfer. • SnO 2 could improve water dissociation. • NiS could enhance water adsorption. [ABSTRACT FROM AUTHOR]

Mediator-free direct dual -Z- scheme Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 hybrid photocatalysts were controllably synthesized by a in-situ growth method for the first time. The as-constructed Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites displayed significantly improved photocatalytic activity for carbamazepine degradation by a factor of 44.9 and 423.1 compared to MgIn 2 S 4 and BiVO 4 , respectively. The mechanism for the enhanced activity was discussed deeply based on the experimental results. A deductive degradation pathway of CBZ was also proposed. • Mediator-free direct dual -Z- scheme Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 hybrid photocatalysts were synthesized. • The photocatalyst exhibited high performance for the degrdation of carbamazepine. • The rate constant improved by a factor of 44.9 and 423.1 compared to MgIn 2 S 4 and BiVO 4 , • A deductive degradation pathway of carbamazepine was proposed. The development of visible-light-driven photocatalysts with high photocatalytic performance is a desired research direction of scholars for energy crisis mitigation and environment restoration. In this study, a series of highly active mediator-free direct dual -Z- scheme Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 hybrid photocatalysts were controllably synthesized by a in-situ growth method for the first time. XRD manifested the coexistence of MgIn 2 S 4 , BiVO 4 and Bi 2 S 3 in the as-prepared nanocomposites. The intimate 2D-2D hetero-junction interfaces between BiVO 4 and MgIn 2 S 4 as well as BiVO 4 and Bi 2 S 3 in the hybrid photocatalysts were verified by TEM and HRTEM. The photocatalytic performance of as-fabricated catalysts was estimated by the degradation of carbamazepine (CBZ) under visible light illumination. The results demonstrated that the as-constructed Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites displayed significantly improved photocatalytic activity for CBZ degradation by factors of 44.9 and 423.1 compared to MgIn 2 S 4 and BiVO 4 , respectively. The enhanced photocatalytic performance of Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites was actually ascribed to the direct dual -Z- scheme migration mechanism, which was proved by XPS analysis, trapping experiments and ESR results. The formation of direct dual -Z- scheme efficiently enhanced the separation of charge carriers. Furthermore, according to DRS, the expanded light absorption in visible wavelength region also contributed to the boosted photocatalytic activity of Bi 2 S 3 /BiVO 4 /MgIn 2 S 4 composites. The photocatalytic degradation products of CBZ were detected and a tentative degradation pathway was proposed. [ABSTRACT FROM AUTHOR]

Graphical abstract Ruthenium phosphide/C 3 N 4 composites were prepared via a in-situ growth method for the first time. The as-obtained photocatalysts show efficient activity hydrogen evolution under visible ligth irradiation. The optimum H 2 evolution rate reached up to 2110 μmol h−1 g−1 for 0.1%-RP/g-CN, which was 113.4 times as high as that of pristine g-C 3 N 4 and 2.22 times of Pt-loaded g-C 3 N 4. Highlights • Ruthenium phosphide/C 3 N 4 composites were prepared via a in-situ growth method for the first time. • The composites exhibited greatly enhanced photocatalytic hydrogen evolution rate. • Well dispersion and intimate interface between ruthenium phosphide and C 3 N 4 nanosheets contributed to the high activity. Abstract The development of materials which meet the needs of both cost-efficiency and high performance for hydrogen evolution reaction is of great importance. However, developing photocatalysts with Pt-like activity still remains as a major challenge. Herein, we utilize ultrafine amorphous ruthenium phosphide (RP) nanoparticles as a high-efficient and robust cocatalyst to enhance the H 2 production activity of g-C 3 N 4 (g-CN). The RP/g-CN samples were prepared based on a facile in-situ growth phosphatization method. The optimum H 2 evolution rate reached up to 2110 μmol h−1g−1 for 0.1%-RP/g-CN, which was 113.4 times as high as that of pristine g-C 3 N 4 and 2.22 times of Pt-loaded g-C 3 N 4. Furthermore, ruthenium is the cheapest platinum-group metal and its amount in the best RP/g-CN sample is only 0.1%, showing the superiority of competitive price and high activity. The introduction of ultrafine amorphous ruthenium phosphide accelerated the transfer rate of electrons and restrain the recombination of charge carriers. The amorphous ruthenium phosphide ultrafine nanoparticles could also serve as cocatalysts for hydrogen evolution. This work provides a promising alternative to expensive Pt-loaded photocatalyst for excellent hydrogen evolution performance under visible light irradiation. [ABSTRACT FROM AUTHOR]

TiO 2 films have received increasing attention for the removal of organic pollutants via photocatalysis. To develop a simple and effective method for improving the photodegradation efficiency of pollutants in surface water, we herein examined the preparation of a P25-TiO 2 composite film on a cement substrate via a sol–gel method. In this case, Rhodamine B (RhB) was employed as the target organic pollutant. The self-generated TiO 2 film and the P25-TiO 2 composite film were characterized by X-ray diffraction (XRD), N 2 adsorption/desorption measurements, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectroscopy (DRS). The photodegradation efficiencies of the two films were studied by RhB removal in water under UV (ultraviolet) irradiation. Over 4 day exposure, the P25-TiO 2 composite film exhibited higher photocatalytic performance than the self-generated TiO 2 film. The photodegradation rate indicated that the efficiency of the P25-TiO 2 composite film was enhanced by the addition of the rutile phase Degussa P25 powder. As such, cooperation between the anatase TiO 2 and rutile P25 nanoparticles was beneficial for separation of the photo-induced electrons and holes. In addition, the influence of P25 doping on the P25-TiO 2 composite films was evaluated. We found that up to a certain saturation point, increased doping enhanced the photodegradation ability of the composite film. Thus, we herein demonstrated that the doping of P25 powders is a simple but effective strategy to prepare a P25-TiO 2 composite film on a cement substrate, and the resulting film exhibits excellent removal efficiency in the degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Polyetherimide-graphitic carbon nitride (PEI- g -C 3 N 4 ) floating photocatalyst has been synthesized by using polyetherimide (PEI) as linker to bind graphitic carbon nitride (g-C 3 N 4 ) together. XRD and XPS analysis for PEI-g-C 3 N 4 show that the interaction between PEI and g-C 3 N 4 does not disturb the structure of g-C 3 N 4 . FTIR, TEM and theoretical results suggest that the long chain PEI binds g-C 3 N 4 particles together to form PEI-g-C 3 N 4 via hydrogen bonding interaction. Based on photodegradation results of methyl orange (MO), PEI can not photodegrade MO and just works as linker in PEI-g-C 3 N 4 , while the photodegradation performance of PEI-g-C 3 N 4 is from the contribution of g-C 3 N 4 . Total organic carbon (TOC) analysis show that nearly 47% organic carbon has been converted into inorganic carbon after photodegradation, suggesting that PEI-g-C 3 N 4 can destroy both N N bond and aromatic rings in MO under light irradiation. The photodegradation efficiency (91%) of MO by g-C 3 N 4 is higher than that (80%) by PEI-g-C 3 N 4 with stirring. But, the photodegradation efficiency (37%) of MO by g-C 3 N 4 is lower than that (55%) by PEI- g -C 3 N 4 without stirring. This is the advantage of floating photocatalyst with respect to the powder photocatalyst since the former can utilize more solar energy than the latter when stirring is not available. [ABSTRACT FROM AUTHOR]

In this study, Ag@AgCl modified titanium phosphate nanoplates (Ag@AgCl/TP) composites were constructed using a two-step approach. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy Dispersive X-Ray Spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and UV–vis diffuse reflectance spectrum (DRS). The Ag@AgCl was observed to be evenly dispersed on the surface of titanium phosphate and the Ag@AgCl composites showed excellent UV–vis absorption, due to the surface plasmon resonance (SPR) of Ag nanoparticles and the heterojunctions between Ag, AgCl and titanium phosphate. The photocatalytic activities of the Ag@AgCl/TP samples were examined under the irradiation of visible light for the photodegradation of Rhodamine B (RhB), reactive brilliant red (X-3B), ciprofloxacin (CIP) and phenol. The Ag@AgCl/TP composites revealed much better photocatalytic performance for these typical organic compounds than pure Ag@AgCl and titanium phosphate. With the help of Photoluminescence spectra and photocurrent tests, this work presented the mechanism for the enhanced photocatalytic performance. The results show that the enhanced activity is due to the surface plasmon resonance effects of Ag and the heterojunctions between Ag, AgCl and TP. Moreover, the possible mechanism of the photocatalytic degradation was presented. [ABSTRACT FROM AUTHOR]

In the present work, an efficient composite photocatalyst composed of 2D BiOBr nanoplates and 2D La 2 Ti 2 O 7 thin nanosheets was synthesized. The photocatalytic performance of the as-obtained samples was investigated by the degradation of dye Rhodamine B and phenol under both UV and visible light irradiation. The results demonstrated that the La 2 Ti 2 O 7 modified with proper amount of BiOBr nanosheets exhibited high efficiency in the photocatalytic process, and the holes took part in the photo-decomposition reaction as the main radicals. The morphology, crystallization, photo-response and electrochemical properties of the obtained catalysts were characterized to understand the mechanism of high photocatalytic activity. The results illustrated that the high photocatalytic performance could be ascribed to the following reasons. First of all, the decoration of BiOBr enlarged the photoresponce of La 2 Ti 2 O 7 to visible light region, thus the composite can be activated to generate more electron and hole pairs. Secondly, the formed BiOBr/La 2 Ti 2 O 7 p-n heterojunction promoted the transfer rate of electrons through the interface and improved the separation efficiency of electron-hole pairs. It is expected that this novel 2D-2D p-n heterostructured photocatalyst would be a promising candidate for environmental remediation. [ABSTRACT FROM AUTHOR]

In this work, BiOCl modified titanium phosphate nanoplates (BiOCl/TP) composite photocatalysts with p-n heterojunctions were prepared by a in-situ growth method. The morphology, crystal structure and optical properties of the prepared samples were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), UV–vis diffuse reflectance spectrometry (DRS). Rhodamine B (RhB), reactive brilliant Red X-3B (X-3B), methylene blue (MB), ciprofloxacin (CIP) and phenol were used to investigate the photocatalytic performance of the prepared samples under ultraviolet light irradiation. Results showed that the BiOCl/TP exhibited much higher activity for the degradation of all these model organic pollutants than pure TP. The mechanism for the enhancement of the photocatalytic performance was established with the help of the results of photocurrent measurements and Photoluminescence spectra. The results illustrated that the enhanced activity could be attributed to the formation of p-n heterojunctions between p-type BiOCl and n-type titanium phosphate, which effectively suppressed the recombination of photo-induced electron-hole pairs. Furthermore, the possible photocatalytic mechanisms on the degradation of the organic pollutants were also proposed. [ABSTRACT FROM AUTHOR]

A facile anion-exchange precipitation method was employed to synthesize 3D flower-like Ag 2 CO 3 /Mg-Al layered double hydroxide composite photocatalyst. Results showed that Ag 2 CO 3 nanoparticles dispersed uniformly on the petals of the flower-like Mg-Al LDH. The obtained nanocomposites exhibited high photocatalytic activities on different organic pollutants (cationic and anionic dyes, phenol) under visible light illumination. The high photocatalytic activity can be ascribed to the special structure which accomplishes the wide-distribution of Ag 2 CO 3 nanoparticles on the surfaces of the 3D flower-like nanocomposites. Therefore, it can provide much more active sites for the degradation of organic pollutant. Then the photocatalytic mechanism was also verified by reactive species trapping experiments in detail. The work would pave a facile way to prepare LDHs based hierarchical photocatalysts with high activity for the degradation of wide range organic pollutants under visible light irradiation. [ABSTRACT FROM AUTHOR]

A novel carbon nitride based self-cleaning hydrogel photocatalyst (KI-PCN gel, potassium and iodine co-doped carbon nitride confined in alginate) has been successfully constructed by a facile method. Fabricated photocatalyst showed enhanced synergistic adsorption-photocatalytic degradation property on a high concentration of methylene blue (HMB) because of enhanced carrier separation efficiency and improved light adsorption capacity of KI-PCN. As expected, the KI-PCN gel showed the highest apparent rate constant value ( K app =0.0310 min−1), which was about 38.8 and 5.8 times as that of blank hydrogel (K app =0.0008 min−1) and PCN gel (K app =0.0053 min−1), respectively. Meanwhile, KI-PCN gel can continuously adsorb low concentration of MB (LMB), and the MB-adsorbed KI-PCN gel can self-clean under light irradiation. The bench-scale experiments simulating real river showed that KI-PCN gel can effectively and continuously remove LMB (0.1–20 ppm), indicating the possibility for the removal of contaminants in natural rivers. Furthermore, the possible degradation pathways were proposed by combining the density functional calculations (DFT) and intermediates identified by liquid chromatography-mass spectrometry (LC-MS). This work proposed a new perspective to acquire a novel self-cleaning and easily recyclable photocatalyst for treatment of wide concentration range organic wastewater as well as remediation of natural waterbody. [Display omitted] • A novel self-cleaning K, I-codoped PCN based hydrogel (KI-PCN gel) was constructed. • Three-dimensional network KI-PCN gel exhibited enhanced adsorption and photocatalytic activity. • KI-PCN gel can remove methylene blue with wide concentration range. • Results of bench-scale tests demonstrate the possible application in real rivers. [ABSTRACT FROM AUTHOR]

In this paper, graphene (GR) and titania co-modified flower-like Bi 2 O 2 CO 3 multi-heterojunction composite photocatalysts were prepared by a simple and feasible two step hydrothermal process. The prepared samples were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectrometry (DRS), photoluminescence (PL), N 2 adsorption–desorption isotherm, and photo-induced current. The photocatalytic activity was investigated by the degradation of MO under UV light irradiation. The as prepared multi-heterojunction GR/Bi 2 O 2 CO 3 /TiO 2 composites exhibited much higher photocatalytic activity than pure Bi 2 O 2 CO 3 , TiO 2 and GR–Bi 2 O 2 CO 3 . The higher performance of GR/Bi 2 O 2 CO 3 /TiO 2 can be ascribed to the formation of multi-heterojunctions, which promote the effective separation of photo-induced electron–hole pairs. Moreover, the higher photocatalytic activity can also be ascribed to the high surface area of GR and TiO 2 , which offers more active sites for the photodegradation reaction. Furthermore, the photocatalytic activity of GR/Bi 2 O 2 CO 3 /TiO 2 remained without striking decrease after five cycles, which indicates the excellent stability of GR/Bi 2 O 2 CO 3 /TiO 2 composites. This work would pave a way to the design of high efficient multi-heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]

Partially reduced ZnO nanorod arrays (NRAs) were synthesized in a reducing reagent of NaBH 4 . The NaBH 4 treatment substantially increased the density of oxygen vacancies. The obtained materials were characterized by a field emission scanning electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy and UV–vis absorption spectra. The photocatalytic activity of the resulting samples was evaluated by degradation of methylene blue (MB) under UV light irradiation. The ZnO NRAs with a partially reduced surface exhibited enhanced photocatalytic activity. The improvement was ascribed to the introducing oxygen vacancies in ZnO by NaBH 4 treatment. The increased surface oxygen vacancy decreased the surface recombination centers, and improved the charge separation efficiency, thus enhances the photocatalytic activity. Furthermore, we found that moderate treatment enhanced photocatalytic activity. However, with longer time of treatment, bulk oxygen vacancies appeared, which would cause a reduced activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Graphene–carbon nanotube titania composite electrode was prepared for the first time. [•] The as-prepared composite photocatalysts show high activity for dye degradation. [•] Effect of carbon nanotube amount on the photocatalytic activity was investigated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nanostructured TiO2 thin films with different morphologies were obtained at low temperature. [•] The effects of the solvent on the morphologies of the products were investigated. [•] The effects of the solvent on the phtocatalytic activity were investigated. [ABSTRACT FROM AUTHOR]

Abstract: CdS-deposited graphene–CNTs hybrid photocatalysts were synthesized by a simple one-step hydrothermal method. The obtained materials were characterized by X-ray diffraction, scanning electron microscopy, UV–vis diffuse reflectance spectroscopy. The photocatalytic activity was investigated by the degradation of methylene blue (MB) under visible light irradiation. An enhanced photoactivity was observed for graphene–CNTs–CdS composites compared to graphene–CdS. The improvement was ascribed to the introduction of CNTs, which could reduce the aggregation of graphene and accelerate the electron transmission rate (reducing the recombination of photo-generated holes and electrons). The results also showed that the optimal mass ratio of CNTs: CdS was 2%. The mechanism of the enhancement in photocatalytic activity was also investigated. [Copyright &y& Elsevier]

• All-solid-state Z-scheme WO 3 nanorod/ZnIn 2 S 4 composite photocatalysts were synthesized. • The photocatalyst exhibited high performance for the degradation of nitenpyram. • The rate constant improved by a factor of 3.8 and 2.5 compared to WO 3 and ZnIn 2 S 4. • A deductive degradation pathway of nitenpyram was proposed. A Z-scheme WO 3 /ZnIn 2 S 4 photocatalyst was synthesized via a simple solvothermal method. Compared with pure WO 3 and ZnIn 2 S 4 , photocatalytic experiments showed that these Z-scheme photocatalysts exhibited enhanced activity for the degradation of nitenpyram (NTP). The apparent rate constant (k) of NTP degradation on 50WZ (WO 3 / 50 wt% Znln 2 S 4) was 0.042 min−1 (∼3.8 times higher than WO 3 and ∼2.5 times higher than ZnIn 2 S 4). Photoluminescence (PL), photocurrent (PC), and electrochemical impedance spectroscopy (EIS) showed that the separation and transfer efficiency of photogenerated carriers in 50WZ was markedly enhanced, which was favorable for improving its photocatalytic activity. Active species capture experiments and electron spin resonance (ESR) measurements showed that superoxide radicals and holes were the main active species for NTP degradation, and they confirmed the formation of the Z-scheme structure. Furthermore, a possible NTP degradation pathway was deduced based on the results of high-performance liquid chromatography mass spectrometry (HPLC-MS). [ABSTRACT FROM AUTHOR]

Abstract: Ag loaded TiO2 nanoplate array which grew on activated carbon fiber (ACF) was prepared in the present work. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis diffuse reflectance spectra (DRS). The photocatalytic degradation of methylene blue (MB) was used to investigate the activity of the synthesized samples. Under both UV and visible light irradiation, the Ag loaded samples showed enhanced photocatalytic activity. Besides, the effect of the deposition dosage of Ag nanoparticles on the photocatalytic activity was also investigated. Under UV light irradiation, the Ag nanoparticles acted as electron traps, which enhanced electron–hole separation efficiency of TiO2. Under visible light irradiation, the Ag nanoparticles showed surface plasmon resonance, which induced the visible light responsive photocatalytic activity for the obtained samples. [Copyright &y& Elsevier]

• A ternary g-C 3 N 4 -CdS/Bi 4 O 5 I 2 composite photocatalysts is prepared by a straightforward self-assembly and calcination method. • Two photogenersted charge transfer pathways are providied in this system. • The adding of Bi 4 O 5 I 2 effectively improves the visible light absorption capacity. • The g-C 3 N 4 -CdS/Bi 4 O 5 I 2 -3 composite achieved the degradation rate of 80% ACE during 25 min. • The performance of g-C 3 N 4 -CdS/Bi 4 O 5 I 2 -3 composite shows no obvious change after 5 cycles. It is a challenge to explore highly efficient photocatalysts for the degradation of pharmaceutical contaminant under visible light. In this work, a series of g-C 3 N 4 -CdS/Bi 4 O 5 I 2 composites were prepared by a simple self-assembly and calcination method. The photocatalysts showed good photocatalytic activity and stability for acetaminophen degradation. The enhanced activity and stability can be ascribed to the reason that the formed ternary heterojunctions provided multi-channel for the transfer of photogenerated charges. Meanwhile, the visible light absorption capacity was improved effectively because of the addition of Bi 4 O 5 I 2. Furthermore, the transfer of holes from CdS to g-C 3 N 4 prohibited the photocorrosion of CdS, thus improving the stability of the composites. The apparent rate constant of the optimal sample (g-C 3 N 4 -CdS/Bi 4 O 5 I 2 -3) for acetaminophen degradation was 5 and 2.5 times as that of g-C 3 N 4 -CdS and pure Bi 4 O 5 I 2. The degradation pathway of acetaminophen was proposed based on the detected intermediates. This work provided an idea to design multi-heterojunction photocatalysts with high performance for the degradation of drug pollutants. [ABSTRACT FROM AUTHOR]

Mediator-free direct dual-Z-scheme g-C 3 N 4 /Ag 3 PO 4 /AgI hybrid photocatalysts were controllably synthesized by an in-situ ion exchange method for the first time. The as-constructed g-C 3 N 4 /Ag 3 PO 4 /AgI composites displayed significantly improved photocatalytic activity for nitenpyram degradation by a factor of 9.3 and 2.9 compared to g-C 3 N 4 and Ag 3 PO 4 , respectively. The mechanism for the enhanced activity was discussed deeply based on the experimental results. A deductive degradation pathway of nitenpyram was also proposed. • Mediator-free direct dual-Z-scheme g-C 3 N 4 /Ag 3 PO 4 /AgI hybrid photocatalysts were synthesized. • The photocatalyst exhibited high performance for the degrdation of nitenpyram. • The rate constant improved by a factor of 9.3 and 2.9 compared to g-C 3 N 4 and Ag 3 PO 4. • A deductive degradation pathway of nitenpyram was proposed. A dual Z-scheme photocatalyst AgI/Ag 3 PO 4 /g-C 3 N 4 (AAC) is prepared by an in-situ ion exchange method from Z-scheme Ag 3 PO 4 /g-C 3 N 4. This dual Z-scheme photocatalyst exhibits higher activity for the degradation of nitenpyram (NTP) than pure g-C 3 N 4 , Ag 3 PO 4 and AgI and their binary composites. The apparent rate constant of NTP degradation for the optimal sample (0.76 min−1) is about 16.2, 2.4 and 2.9 times as that of g-C 3 N 4 , Ag 3 PO 4 and AgI, respectively. The results of photoluminescence spectroscopy and transient photocurrent response show that the separation efficiency of photogenerated electrons and holes for AAC is significantly improved, which is beneficial to improve its photocatalytic activity. Active species capture experiments and electron spin resonance spectra show that superoxide radicals and holes are the main active substances for NTP degradation and prove the formation of Z-scheme structure. In addition, basing on the results of high-performance liquid chromatography mass spectrometry, a possible degradation pathway of NTP is deduced. [ABSTRACT FROM AUTHOR]

• TiO 2 /g-C 3 N 4 intimately coupled with in-situ cultivated biofilm for nitrate reduction. • ICPB enhanced the removal rate of nitrate without additional electron donors. • ICPB resulted in the low production of harmful products and high selectivity of N 2. • Microbial community were optimized to adapt the environment for denitrification. Nitrogen pollution has become a major threat to the aquatic environment, and the key to solve this problem is to enhance the nitrate reduction in water. Intimately coupled photocatalysis and biodegradation (ICPB) is a novel technique for degradation of bio-recalcitrant pollutants; however, it has not been used for nitrate reduction. This study applied a system that intimately coupled TiO 2 /g-C 3 N 4 photocatalysts and in-situ cultivated biofilms for nitrate reduction in water without additional electron donors. The result shows a nitrate removal rate up to 40.3% in ICPB after 16 h. Furthermore, the N 2 selectivity was 86.3%, which was higher than that for other protocols. In ICPB, nitrate was first reduced to nitrite, which was mainly contributed to the effect of biofilms. Then, nitrite was reduced via the cooperation of photocatalysts and biofilms, which benefited both low production of undesirable products and high selectivity of N 2. Moreover, the growth of the microbes during the ICPB were favorable for denitrification. In conclusion, light-induced electrons generated from TiO 2 /g-C 3 N 4 were harvested by microbes, optimizing the community structure of biofilms toward nitrate reduction. This study provides a new strategy to enhance the nitrate reduction in water and an insight into the reduction mechanism of nitrate in ICPB. [ABSTRACT FROM AUTHOR]

• Composite photocatalysts combining the advantages of homojunction and heterojunction were prepared. • The photocatalyst exhibited high performance for the degradation of acetaminophen. • A deductive degradation pathway of acetaminophen was proposed. Bi 4 O 5 I 2 loaded anatase-TiO 2 (B) biphase nanowires composite photocatalysts were fabricated by an in situ calcination method and exhibited outstanding photocatalytic activity. The microstructure, optical performance and band structure of the composite photocatalysts were investigated by relevant characterizations. The results demonstrated the successful formation of heterojunction between anatase-TiO 2 (B) biphase nanowires and Bi 4 O 5 I 2 , which integrated the advantages of homojunction and heterojunction. Therefore, it definitely improved separation efficiency of photo-induced electron-holes because of the formation of multi-junctions. In order to test the enhanced photocatalytic activity, acetaminophen was chosen as target pollutant. The sample with 67% Bi 4 O 5 I 2 (TiO 2 -Bi 4 O 5 I 2 -3) presented the highest photocatalytic activity on the degradation of acetaminophen and its reaction apparent rate constant was 10 and 25 times as that of Bi 4 O 5 I 2 and TiO 2 biphase nanowires, respectively. Through trapping experiments and LC–MS/MS analysis, OH was proved to be the key active specie during the photocatalytic process of acetaminophen degradation. Meanwhile a possible degradation pathway was proposed based on the detected intermediate products. [ABSTRACT FROM AUTHOR]