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Polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health effects in humans, and the photocatalysis degradation is regarded as promising technology to remove contaminants from environment. Although many TiO 2 -based photocatalysts were reported to be active for this process, the efficiency is still quite low. In this work, graphene oxide (GO) enwrapped silver phosphate composites were found to exhibit superior activities in the photocatalytic degradation process of a variety of PAHs (naphthalene, phenanthrene and pyrene) under visible light irradiation. The optimum amount of GO was 3.0 wt%. Within several minutes or even seconds’ visible light irradiation, naphthalene, phenanthrene and pyrene can be completely oxidized. Meanwhile, good photocatalytic activity was retained after six cycles run. The trapping experiments gave evidence that degradation was mediated by photogenerated holes, superoxide radicals and hydroxyl radical, different from others OH was found to play a role in the process of pyrene photoreaction. Gas chromatography-mass spectrometer (GC-MS) technique was employed to analyze photodegradation intermediates. Based on the identified intermediates, the plausible photooxidation pathways of PAHs over the surface of GO/Ag 3 PO 4 were proposed. Ultimately, a possible synergetic mechanism associated with Ag surface plasmon resonance effect of GO/Ag 3 PO 4 composite for PAHs photodegradation was suggested. The superior photocatalytic system for the removal of PAHs was presented and simultaneously it shed light on photodegradation of PAHs from a practical point of view. [ABSTRACT FROM AUTHOR]

The photocatalytic performance of the g-C 3 N 4 photocatalyst was restricted by the low efficiency because of the fast charge recombination. The present work constructed a “killing two birds with one stone” composite (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 /g-C 3 N 4 heterostructured photocatalysts with the aim to greatly promote the charge separation and recycle decatungstate in aqueous solution. Decatungstate was immobilized on g-C 3 N 4 in the form of modified decatungstate (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 via surface bonding method for the first time. Furthermore, a novel ternary (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 /g-C 3 N 4 /rGO photocatalyst was successfully constructed by integrating graphene into the binary (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 /g-C 3 N 4 composite as the electron mediator. The photocatalysts were characterized by XRD, FTIR, FESEM, TEM, UV-vis DRS, PL and EIS measurement. The photocatalytic properties were evaluated in photodecomposition of aqueous methyl orange and phenol under visible-light irradiations. It has been shown that the obtained (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 /g-C 3 N 4 photocatalyst exhibited improved photocatalytic activity and enhanced reduced charge recombination as compared with those of g-C 3 N 4 and (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 . It has been found that the introduction of graphene revealed a synergistic effect between the (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 species, g-C 3 N 4 and graphene existed in the ternary photocatalyst. Consequently, the photocatalytic activity of the ternary (C 16 H 33 (CH 3 ) 3 N) 4 W 10 O 32 /g-C 3 N 4 /rGO photocatalyst was superior to that of the binary one, originating from its stronger visible-light absorption and more reduced charge combination. Finally, recycling experiments revealed that the ternary composite photocatalyst was not only highly efficient but also robust, because it can be used six times without loss of activity, which efficiently solved the problem of recycling decatungstate in reaction system. This work demonstrated that rational design and construction of g-C 3 N 4 -decatungstate composites could open up a new avenue for the development of new efficient visible-light photocatalysts for water disinfection. [ABSTRACT FROM AUTHOR]

A highly efficient visible-light-driven acidified g-C 3 N 4 (ACNS)/g-C 3 N 4 isotype heterojunction photocatalysts were synthesized by ultrasonic dispersion assisted electrostatic self-assembly strategy for the first time. The photocatalytic oxidation ability of the novel photocatalysts were evaluated using methyl orange (MO) as a target pollutant. The obtained ACNS/g-C 3 N 4 photocatalysts were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectrometry (FTIR), UV–vis diffuse reflection spectroscopy (DRS), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) methods. The photocatalysts exhibited a significantly enhanced photocatalytic performance in degrading MO under visible light illumination (λ > 420 nm) compared with the pristine ACNS and g-C 3 N 4 solely. The optimal ACNS content for the photocatalytic activity of the heterostructured composites was determined. The 30 wt.% ACNS/g-C 3 N 4 exhibited the highest photocatalytic activity, which showed a reaction rate constant as high as 0.0216 min −1 , 4.3 times higher than that of bare g-C 3 N 4 . The mechanism of the photocatalysts was investigated by determination of reactive species in the photocatalytic reactions and photoluminescence technique. The quenching effects of different scavengers displayed that the reactive h + and O 2 − played major role in the reaction systems. The synergic effect between the ACNS and g-C 3 N 4 was found to lead to an improved photo-generated carrier separation and hence the photocatalytic activities of the composite photocatalysts were increased significantly. [ABSTRACT FROM AUTHOR]

This study developed a facile approach for preparing Ti3+ self-doped TiO2-graphene photocatalyst by a one-step vacuum activation technology involved a relative lower temperature, which could be activated by the visible light owing to the synergistic effect among Ti3+ doping, some new intersurface bonds generation and graphene oxide reduction. Compared with the traditional methods, the vacuum activation involves a low temperature and low-costing, which can achieve the reduction of GO, the self doping of Ti3+ in TiO2 and the loading of TiO2 nanoparticles on GR surface at the same time. These resulting TiO2-graphene composites show the high photodegradation rate of MO, high hydrogen evolution activity and excellent IPCE in the visible light irradiation. The facile vacuum activation method can provide an effective and practical approach to improve the performance of TiO2-graphene and other metal oxides-graphene towards their practical photocatalytic applications. [ABSTRACT FROM AUTHOR]

Effective and durable photocatalysts are essential for the decomposition of persistent contaminants and the generation of hydrogen peroxide. In this study, we successfully constructed an S-type heterojunction by in situ growing Bi 2 O 3 nanocrystals and NH 2 -MIL-101(Fe) onto surface-modified g-C 3 N 4. The process of charge transfer in the S-type heterojunction was confirmed using ISI-XPS, DFT calculations, capture experiments, and EPR signals. The combined influence of the heterojunction and MOF demonstrated remarkable photocatalytic performance in the breakdown of tetracycline (TC) and the generation of hydrogen peroxide (H 2 O 2). In the enhanced setup (10%–NH 2 –MIL-101(Fe)@MCN/Bi 2 O 3), full degradation of TC was accomplished within 50 min under visible light exposure. Additionally, a notable H 2 O 2 yield of 655.63 μmol/g was attained, all achieved without the necessity of sacrificial agents or supplementary oxygen. Based on the outcomes of the dual functionality, the exceptional performance of the ternary composite material can be ascribed to the collaborative influence of the heterojunction and MOF. This collaborative effect expands the light absorption range in the visible region, suppresses the recombination of electron-hole pairs, and enhances the photocatalytic redox ability. The system demonstrates significant potential in the efficient in situ production of H 2 O 2 and removal of recalcitrant organic pollutants in pure water. [Display omitted] • A novel NH 2 -MIL-101(Fe)@MCN/Bi 2 O 3 photocatalyst was synthesized. • Effective charge carrier separation and utilization were achieved through the synergistic effects of the S-type heterojunction and MOF. • High efficiency in the degradation of pollutants and generation of H 2 O 2 under visible light. [ABSTRACT FROM AUTHOR]

Intimately coupled photocatalysis and biodegradation (ICPB) systems represent a promising wastewater treatment technology. The implementation of ICPB systems for oil spill treatment is a pressing concern. In this study, we developed an ICPB system comprising BiOBr/modified g-C 3 N 4 (M-CN) and biofilms for the treatment of oil spills. The results demonstrate that the ICPB system achieved the rapid degradation of crude oil, outperforming the single photocatalysis and biodegradation methods by degrading 89.08 ± 5.36% within 48 h. The combination of BiOBr and M-CN formed a Z-scheme heterojunction structure, enhancing the redox capacity. The interaction between the holes (h+) and the negative charge on the biofilm surface promoted the separation of electrons (e−) and h+, thereby accelerating the degradation process of crude oil. Moreover, ICPB system maintained an excellent degradation ratio after three cycles and its biofilms progressively adapted to the adverse effects of crude oil and light. The microbial community structure remained stable throughout the degradation of crude oil, with Acinetobacter and Sphingobium identified as the dominant genera in biofilms. The proliferation of the Acinetobacter genus appeared to be the main factor contributing to the promotion of crude oil degradation. Our work demonstrates that the integrated tandem strategies perhaps represent a feasible pathway toward practical crude oil degradation. [Display omitted] • Integrated biodegradation and photocatalysis facilitate crude oil degradation. • The Z-scheme heterojunction of BiOBr/M-CN enhances the electron-hole separation. • Microorganisms inside the carrier play a central role in degradation of crude oil. • Binding of holes with negative charge of biofilms sophisticates the ICPB system. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Mn 3 O 4 /MnO 2 -cubic Ag 3 PO 4 photocatalysts (MnO x -cAP) were prepared. • MnO x -cAP showed enhanced photocatalytic activity for phenanthrene degradation. • Intimately coupled photocatalysis & biodegradation by vis-light (VPCB) was studied. • MnO x -cAP based VPCB promoted phenanthrene removal by～12% over VPC. • VPCB pathways of phenanthrene were proposed based on the GC-MS analysis. Abstract Polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health effects in humans. The intimately coupled photocatalysis and biodegradation (ICPB) is considered as a prospective green technique to clean up pollutants from environment. In this work, the Mn 3 O 4 /MnO 2 -cubic Ag 3 PO 4 with exposed {1 0 0} facets (MnO x -cAP) exhibited enhanced photocatalytic activity for the degradation of typical PAHs (phenanthrene) under visible light illumination. The photocatalysts were characterized by XRD, FESEM, TEM, FTIR, Raman, UV-vis DRS, PL, BET and XPS. Noticeably, 0. 4 wt % MnO x -cAP composite exhibited the optimal photocatalytic activity with the degradation efficiency of phenanthrene (PHE) up to 96.2% within 20 min. Cyclic tests indicated the stability of MnO x -cAP composite over repeated use. A photocatalytic degradation mechanism associated with Ag surface plasmon resonance (SPR) effect over MnO x -cAP composite was proposed. Subsequently, this research estimated the elimination and mineralization of PHE using visible light-induced ICPB (known as VPCB) with 0. 4 wt % MnO x -cAP as the photocatalyst. In the first 2 h of assay, VPCB accelerated PHE elimination by ∼9% compared with photocatalysis alone. The biofilms in the VPCB sponge carriers evolved to being enriched in Shewanella , Sedimentibacte r, Comamonas , Acinetobacter and Pseudomonas. The intermediates were analyzed by gas chromatography-mass spectrometer (GC-MS) technique and plausible VPCB pathways of PHE were proposed. PHE was transformed to non-toxic intermediates in 10 h. It seemed that the MnO x -cAP based VPCB would be promising for degrading persistent PAHs from a realistic point of view. [ABSTRACT FROM AUTHOR]

• PCCN v were synthesized with (NH 4) 3 PO 4 and Agar by one-step process. • Electron-localized heptazine units was delocalized by CP in PCCN v. • In-plane CP and interlayers' C N interaction boosted carriers' separation. • PCCN v exhibited superior photodegradation efficiency for alkanes. • Catalytic mechanism, reaction path and toxicities were investigated. The electron localized heptazine units make it difficult to separate photoinduced electeron-hole pairs for graphitic carbon nitride (g-C 3 N 4), which limits the application prospect of graphitic-like carbon nitride. Changing inherent N-(C) 3 bridging mode of in-plane heptazine units and built more electron channel could be a reasonable strategy. Herein, "carbon patches" were introduced to stitch heptazine units, high speed electron transfer path were thus constructed due to delocalized p orbital electron in "carbon patches" as a result. Simultaneously, interlayers' high speed electron transfer channel was also constructed by distorted molecular layer because of presence of large electronegative interstitial phosphorus atoms. Such photoinduced electron-holes' spatial separation in-plane and interlayers were built concurrently and confirmed by XANES and DFT calculation for the first time. The resulted PCCN v series photocatalysts exhibited superior photon absorption capability, excellent charge carriers' separation kinetics, good O 2 molecule adsorption as well as activation capability, the resulted abundant reactive radicals contributed to petroleum hydrocarbons photocatalytic degradation significantly. This work shed light on efficient separation of photoinduced excition for carbon nitride in photocatalysis, simultaneously presented a promising candidate non-metal photocatalytic environmental material for marine oil spill remediation. [ABSTRACT FROM AUTHOR]