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• Novel Ag-bridged Z-scheme 3D/3D g-C 3 N 4 /BiOI heterojunction was constructed. • 91.8% TC degradation was achieved with 0.4 g/L catalyst under visible light. • Z-scheme plasmonic heterojunction formation evolves efficient charge separation. • Four TC degradation pathways were proposed according to identified intermediates. • Plausible mechanism for the exceptional photocatalytic activity was put forward. Rational design and synthesis of highly efficient and robust photocatalysts with positive exciton splitting and interfacial charge transfer for environmental applications is critical. Herein, aiming at overcoming the common shortcomings of traditional photocatalysts such as weak photoresponsivity, rapid combination of photo-generated carriers and unstable structure, a novel Ag-bridged dual Z-scheme g-C 3 N 4 /BiOI/AgI plasmonic heterojunction was successfully synthesized using a facile method. Results showed that Ag-AgI nanoparticles and three-dimensional (3D) BiOI microspheres were decorated highly uniformly on the 3D porous g-C 3 N 4 nanosheet, resulting in a higher specific surface area and abundant active sites. The optimized 3D porous dual Z-scheme g-C 3 N 4 /BiOI/Ag-AgI manifested exceptional photocatalytic degradation efficiency of tetracycline (TC) in water with approximately 91.8% degradation efficiency within 165 min, outperforming majority of the reported g-C 3 N 4 -based photocatalysts. Moreover, g-C 3 N 4 /BiOI/Ag-AgI exhibited good stability in terms of activity and structure. In-depth radical scavenging and electron paramagnetic resonance (EPR) analyses confirmed the relative contributions of various scavengers. Mechanism analysis indicated that the improved photocatalytic performance and stability were ascribed to the highly ordered 3D porous framework, fast electron transfer of dual Z-scheme heterojunction, desirable photocatalytic performance of BiOI/AgI and synergistic effect of Ag plasmas. Therefore, the 3D porous Z-scheme g-C 3 N 4 /BiOI/Ag-AgI heterojunction had a good prospect for applications in water remediation. The current work provides new insight and useful guidance for designing novel structural photocatalysts for environment-related applications. [Display omitted] [ABSTRACT FROM AUTHOR]

TiO2, as a benchmark in the field of ultraviolet photocatalysis, is one of the most widely used semiconductor photocatalysts. However, its inherent drawbacks, including wide bandgap and fast recombination of charge carriers, lead to the underutilization of solar light. Increasing the overall solar spectrum utilization of TiO2, especially in the near‐infrared region (NIR, ≈52%), is the key to efficient solar energy conversion. In this review, the strategies to enhance NIR light capture of TiO2‐based photocatalysts, including hybridization with narrow optical gap semiconductors, bandgap engineering, upconversion materials, plasmonic materials, and photosensitizers, are elaborated. The basic mechanisms for NIR light conversion employed by TiO2 and the preparation methods of photoactive materials are summarized. Furthermore, their applications in photocatalytic pollutants purification, hydrogen and oxygen evolution, multifunctional smart windows, nitrogen photofixation, as well as carbon dioxide photoreduction and photocatalytic disinfection are discussed. Finally, this review presents the limitations and perspectives for the future development of efficient NIR solar photon conversion of TiO2‐based materials. [ABSTRACT FROM AUTHOR]

Abstract Graphene enhanced WO3 has recently become a promising material for various applications. The understanding of the transfer of charge carriers during the photocatalytic processes remains unclear because of their complexity. In this study, the characteristics of the deposited WO3/graphene layered materials were investigated by Raman spectroscopy, UV–vis spectroscopy, and SEM. According to the results, p-graphene exhibits and enhances the characteristics of the WO3/graphene film. The photocatalytic activities of WO3/graphene layered materials were assessed by the photocatalytic degradation of oxytetracycline antibiotics as irradiated by UV light. Here, a higher current of cyclic voltammetry and a higher resistance of impedance spectra were obtained with the as-grown WO3/graphene directly synthesized on Cu foils under UV light using an electrochemical method, which was different from traditional WO3 catalysts. Thus, it is urgent to explore the underlying mechanism in depth. In this study, a large layered material WO3/graphene was fabricated on a Si substrate using a modified CVD method, and a WO3/graphene device was developed by depositing a gold electrode material and compared with a WO3 device. Due to photo-induced doping effects, the current-voltage test suggested that the photo-resistance is larger than dark-resistance, and the photo-current is less than the dark current based on WO3/graphene layered materials, which are significantly different from the characteristics of the WO3 layered material. A new pathway was developed here to analyze the transfer properties of carriers in the photocatalytic process.

Bi 5 O 7 I-based photocatalysts have been extensively employed for wastewater photocatalysis thanks to their desirable catalytic properties. This review sums up the latest progress in Bi 5 O 7 I-based heterojunctions and provides crucial information about three main areas: synthesis approaches, characterizations, and their applications in wastewater photocatalysis. Special attention is given to the synthetic strategies, like co-precipitation, hydrothermal, solvothermal, sonication, and ionic liquid self-combustion, to obtain Bi 5 O 7 I-based heterojunctions with appropriate morphology, structure, physical, chemical, and optical characteristics. Deeply, it was detected that the structure of Bi 5 O 7 I inclines to build a 3D crystal structure by stacking the [Bi 5 O 7 ]+ slices with I− ions. Beyond that, the Bi 5 O 7 I nanomaterials exhibited different morphologies, like nanoparticles, nanorods, nanosheets, and flower-like microspheres, manifesting excellent support structures to immobilize incorporated co-catalysts. Our review also highlights the major modification approaches, like doping, type II, p-n, Z-type, and S-type heterojunctions, that address the catalytic limitations of pristine Bi 5 O 7 I. Impressively, the density functional theory (DFT) calculations played a crucial role in simulating and characterizing the crystalline structure, band structure, work function, and charge transfer profile of these Bi 5 O 7 I-based heterojunctions. In more detail, doping with plasmonic nanoparticles could broaden the visible-light sensitivity of newly created Bi 5 O 7 I-based heterojunctions. Even though type II and p-n Bi 5 O 7 I-based heterojunctions allowed for excellent charge separation mechanisms, their redox potentials were insufficient to produce both •OH and •O 2 − radicals. On the other hand, Bi 5 O 7 I-based S-type and Z-type systems offered advantages for obstructing the charge reintegration rate, accelerating the photocarrier migration, expanding the photon absorption, and upgrading the redox potential. The applications of Bi 5 O 7 I-based heterojunctions in terms of the purification of pollutants are also reviewed, supported by a huge number of impactful experimental studies and DFT theoretical calculations. The Bi 5 O 7 I-based heterojunctions displayed superior catalytic performance against various environmental pollutants, like phenolic compounds, organic dyes, pharmaceuticals, microorganisms, Hg0, Cr(VI), and so on. The DFT calculations reflected an assistance role in proposing the degradation pathways of treated organic pollutants via Bi 5 O 7 I-based heterojunctions. Ultimately, this review may have a significant influence on the development of sustainable Bi 5 O 7 I-based photocatalysts with perfect photocatalytic properties. [Display omitted] • This review summarizes the latest progress in Bi 5 O 7 I-based heterojunction photocatalysts. • Special attention is given to the synthetic strategies of Bi 5 O 7 I-based composites. • The characterizations and the photoactivity of Bi 5 O 7 I-based catalysts have been explained in detail. • Modification strategies like doping, defects, and heterojunctions have been discussed. • The DFT calculations played a crucial role in justifying the catalytic behavior of Bi 5 O 7 I-based catalysts. [ABSTRACT FROM AUTHOR]

The strategy of nitrogen sufficiency conversion can improve ammonium nitrogen (NH 4 +-N) removal with microalgal cells from ammonium-rich wastewater. We selected and identified one promising isolated algal strain, NCU-7, Chlorella sorokiniana , which showed a high algal yield and tolerance to ammonium in wastewater, as well as strong adaptability to N deprivation. The transition from N deprivation through mixotrophy (DN, M) to N sufficiency through autotrophy (SN, P) achieved the highest algal yields (optical density = 1.18 and 1.59) and NH 4 +-N removal rates (2.5 and 4.2 mg L−1 d−1) from synthetic wastewaters at two NH 4 +-N concentrations (160 and 320 mg L−1, respectively). Algal cells in DN, M culture obtained the lowest protein content (20.6%) but the highest lipid content (34.0%) among all cultures at the end of the stage 2. After transferring to stage 3, the lowest protein content gradually recovered to almost the same level as SN, P culture on the final day. Transmission electron microscopy and proteomics analysis demonstrated that algal cells had reduced intracellular protein content but accumulated lipids under N deprivation by regulating the reduction in synthesis of protein, carbohydrate, and chloroplast, while enhancing lipid synthesis. After transferring to N sufficiency, algal cells accelerated their growth by recovering protein synthesis, leading to excessive uptake of NH 4 +-N from wastewater. This study provides specific insights into a nitrogen sufficiency conversion strategy to enhance algal growth and NH 4 +-N removal/uptake during microalgae-based ammonium-rich wastewater treatment. [Display omitted] • Chlorella sorokiniana (NCU-7) performed well in growth and NH 4 +-N removal in NH 4 +- rich wastewater. • Nitrogen sufficiency conversion strategy improved algal yield and NH 4 +-N removal from wastewater. • High algal yield and protein synthesis in DN, M culture contributed to the over-uptake of NH 4 +-N. • Algal cell reduced N and protein contents by downregulating protein synthesis under N deprivation. • Recovered metabolic pathway of algal cell synthesized more protein and promoted NH 4 +-N removal. [ABSTRACT FROM AUTHOR]

Applying photocatalytic technology to remove pollutants in wastewater represents an ideal pathway to solve the crisis of environmental contamination. However, It's always a great challenge to design efficient, recyclable and multifunctional photocatalysts. Herein, the x wt% Bi/BiPMo 12 O 40 (x = 0.5, 1.0, 2.0 and 3.0) composites were successfully constructed via a hydrothermal method, and characterized with a variety of technological methods. These composites displayed enhanced and persistent photocatalytic activity for removing various pollutants. Specifically, the 1.0% Bi/BiPMo 12 O 40 exhibited optimal performance with the removal efficiencies of 89.33% (Cr(VI)), 77.5% (TC) and 97.5% (MO) under visible light (λ＞420 nm), respectively. Moreover, the influence factors including the Cr(VI) concentration, catalyst dosage, the pH of solution, water quality and inorganic anions, on Cr(VI) reduction were studied in detail. Meanwhile, the degradation products of TC were identified with HPLC-MS, and a feasible degradation pathway was established. The toxicity of intermediates was assessed through QSAR prediction. The outstanding catalytic activity could be attributed to the strong visible absorption, enhanced BET specific surface area and the promotion in separation of photoinduced carriers. Capturing experiments and ERS tests verified the main active substances for Cr reduction (·O 2 − and e−) and TC degradation (·O 2 −, ·OH and h+). Eventually, the reasonable photocatalytic mechanism was proposed. This work provides a rational strategy for designing and constructing of efficient and durable POMs-based catalysts for environmental modification. Novel Bi/BiPMo 12 O 40 composites were successfully fabricated via a hydrothermal method and demonstrated outstanding and persistent visible-light catalytic performance for Cr(VI) reduction and TC/MO degradation, which resulted from the SPR effect of Bi NPs and the Schottky junction between Bi NPs and BiPMo 12 O 40. [Display omitted] • Bi/BiPMo 12 O 40 composites showed good visible-light catalytic activity. • The effects of operating parameters on Cr(IV) reduction were studied. • The degradation pathways of TC were investigated by HPLC-MS. • The toxicity of TC degradation products was evaluated by QSAR prediction. [ABSTRACT FROM AUTHOR]

The accumulation of highly fluid and biotoxic hexavalent chromium (Cr(VI)) impairs water ecosystems. It is urgent to quickly reduce Cr (VI) to trivalent chromium (Cr (III)) in wastewater. Hereby, Z-scheme MgIn 2 S 4 /BiPO 4 heterojunction was prepared, and MB-30 (mass ratio of BiPO 4 to composite) presented a rapid Cr(VI) (10 mg L−1) removal efficiency of 100% within 10 min, its kinetic rate constant was 9.0 and 30.1 folds that of MgIn 2 S 4 and BiPO 4 , respectively. After four rounds, MB-30 maintained a high removal rate of 93.18% and stabilized crystal texture. First-principles calculations revealed that the formation of Z-scheme heterojunction could ameliorate charge generation, detachment, migration capability, and light utilization. Meanwhile, the coupling of S and O in the two components produced a tight S–O bond, which acted as an atomic-level access to promote carrier migration. The findings were consistent with the structure superiority and optical and electronic properties of MB-30. The Z-scheme pattern was substantiated based on multifarious experiments, which exhibited an elevated reduction potential while emphasizing the significance of interfacial chemical bond and the internal electric field (IEF) on carrier detachment and migration. [Display omitted] • MB-30 rapid reduction of Cr(VI) in 10 min under visible irradiation. • MB-30 enhanced charge engenderment, detachment and migration efficiency, and light absorption capacity. • Z-scheme heterostructure and interfacial S–O bond expedited charge transfer and enhanced reduction capacity. • Combining DET calculation with experiment to discuss the principle of Cr (VI) catalytic reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • A systematic component pairing method is proposed for associative extraction. • COSMO-RS model is used to predict extraction performance and SLE. • Two exemplary separation cases validate the applicability of pairing method. • Suitable HBAs and liquid operating window are determined experimentally. • Associative extraction mechanism is unraveled by FT-IR and DFT. Associative extraction by selectively forming deep eutectic solvent (DES) with the target solute exhibits high performance toward many hard-to-separate systems; however, selecting a proper associative extractant for a specific task is challenging as high extraction efficiency and forming liquid DES should be satisfied simultaneously. In this work, a systematic component pairing method is proposed to rationally select suitable hydrogen bond acceptors (HBA) for associative extraction, which includes three steps: collecting HBA candidates, theoretical pairing from extraction potential evaluation and solid–liquid phase behavior estimation, and experimental validation. For two exemplary separation cases, (i.e., detergent range alcohol-alkane mixture and phenol-toluene mixture), suitable HBAs with high extraction performance and wide liquid operating window are successfully selected, demonstrating the reliability of the method. Hydrogen bonding interaction drives the selective formation of DES with the target solute, and the interaction strength depends on the solute structure, which in turn determines the selection of suitable HBAs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Urchin-like TiO 2 /Ti 3 C 2 O x (MXene) photocatalysts have been successfully fabricated. • Surface -O terminated Ti 3 C 2 O x has a work function about 0.3 eV higher than that of TiO 2. • The photocatalytic H 2 evolution and LEV degradation of TiO 2 /Ti 3 C 2 O x are 9.7 and 6.7 folds higher than those of TiO 2 , respectively. • The photocatalytic reaction pathways were carefully investigated. • The photogenerated carriers were efficiently separated at the TiO 2 /Ti 3 C 2 O x interface. The surface groups of MXene act as a decisive role on the performance of MXene-based photocatalysts. In this work, TiO 2 nano-whiskers were grown in-situ on Ti 3 C 2 T x , through a hydrothermal and post-heat treatment process, meanwhile, the surface groups of Ti 3 C 2 T x were unified -O adsorption. The as-prepared urchin-like TiO 2 /Ti 3 C 2 O x composite have efficient activity for photocatalytic hydrogen evolution and degradation of levofloxacin (LEV). The optimized hydrogen evolution reaction (HER) performance reached 346.8 μmol g-1 h−1, and the apparent quantum yield at 313 nm was 7.67%. Its hydrogen production performance and degradation rate of LEV were 9.7 and 7.7 folds higher than those of pure TiO 2 , respectively. The -O terminated Ti 3 C 2 O x achieving a work function about 0.3 eV larger than TiO 2 , as both DFT calculation and UPS measurement depicted. Therefore, the photogenerated e-/h+ were separated at the TiO 2 /Ti 3 C 2 O x interface via Schottky junction, a large amount of e- was enriched on Ti 3 C 2 O x , which enabled the photocatalyst with remarkable charge separation and photocatalytic performance. Meanwhile, the reaction pathways of TiO 2 /Ti 3 C 2 O x photocatalytic HER and LEV degradation/mineralization were carefully investigated. This study underlines the significance of surface groups on photocatalysts composed of MXenes, and sheds light on the new approach to the rational design of high-efficiency MXene-based photocatalysts. [ABSTRACT FROM AUTHOR]

A novel type of Bi/PMo 12 doped TiO 2 composite was successfully constructed through a simple electrospinning/calcination technology and hydrothermal method. These materials demonstrated outstanding and durable visible-light catalytic ability for pollutants degradation (TC, EFA and MO), which resulted from the PMo 12 doping, SPR effect of Bi NPs and the Schottky junction between Bi NPs and PMo 12 doped TiO 2. The influence factors (dosage of catalyst, concentration of TC, the pH of solution, reaction temperature, inorganic anions, water quality) on TC degradation were comprehensively investigated. The possible TC degradation pathways were established based on the identification of degradation products by HPLC-MS. The toxicity of intermediates was also assessed through QSAR prediction. [Display omitted] • Bi/PMo 12 doped TiO 2 was prepared via electrospinning and hydrothermal methods. • They showed good visible-light degrade activity for various pollutants. • The effect of operating parameters on TC degradation was detailedly studied. • The possible degradation pathways of TC were investigated by HPLC-MS. • The toxicity of TC degradation intermediates was assessed by QSAR prediction. Exploration of visible-light-responsive, efficient and durable photocatalysts is of great concern for removing organic dyes and antibiotics from the wastewater. Herein, a series of mesoporous TiO 2 -doped with polyoxometalates [H 3 PMo 12 O 40 ] (PMo 12) and loaded with Bi nanoparticles (NPs) composites were fabricated through a convenient electrospinning/calcination and hydrothermal methods, which was labelled as × wt% Bi/PMo 12 doped TiO 2 (abbr. x % Bi/PT, x = 10, 20 and 30, respectively). In these composites, polyoxometalate PMo 12 acts as a dopant to reduce the band gap value of TiO 2 , effectively expanding its visible light absorption and enhance its photocatalytic redox ability. Moreover, the Schottky junction between Bi NPs and PT further promotes the separation efficiency of the photoinduced carriers. Therefore, these as-prepared catalysts demonstrated outstanding and persistent photocatalytic activity for removing tetracycline (TC), enrofloxacin (EFA) and methyl orange (MO) with visible-light (λ > 420 nm) illumination. Especially, 20 % Bi/PT specimen presented the optimal catalytic performance, whose degradation efficiencies for TC, EFA and MO reached 86.0 %, 90.9 % and 92.5 % with k = 0.03019, 0.01275 and 0.01199 min−1, respectively. The superoxide radical (⋅O 2 –), hydroxyl radical (⋅OH) and holes (h+) were proved to be the dominating active species in contaminants degradation through the trapping tests and electron spin resonance (ESR) measurements. Furthermore, the possible TC degradation pathways were established based on the identification of degradation products by high performance liquid chromatography-mass spectrometry (HPLC-MS). The toxicity of intermediates was also assessed through QSAR prediction. According to the energy band structure analysis, the corresponding photocatalytic mechanism was revealed. The current work provides several new insights for the design and preparation of low cost, efficient, stable and versatile photocatalysts. [ABSTRACT FROM AUTHOR]

Algal biofilm cultivation has great potential in producing high biomass yields and reducing harvesting costs. Organic carbon sources can promote algal growth in suspended cultivation, but their effects on algal biofilm formation and related mechanism have rarely been studied. In this study, we determined the most suitable organic carbon source and its concentration for the formation of algal biofilm, and structure/composition characteristics of extracellular polymeric substances (EPS) from algal biofilm. The results showed that the glycerol concentration of 1000 mg C L−1 in algal biofilm system was the most suitable condition to contribute to the biofilm formation and enhance attached biomass among the treatments. The algal biofilm at the glycerol concentration excreted the contents of relatively high EPS and its protein (EPS-PN), which were beneficial to forming the biofilm. The high EPS-PN content was mainly attributed to the increased hydrophobic proline and alanine contents but declined hydrophilic glutamic acid for improving algal biofilm formation. These findings enhanced our understanding of the formation mechanism of algal biofilm under the organic carbon source condition and provided the theoretical basis for algal biofilm formation. [Display omitted] • The glycerol concentration of 1000 mg C L−1 contributed to algal biofilm formation. • Algae at the glycerol condition excreted high EPS and EPS-PN for biofilm formation. • The high EPS-PN was mainly caused by the increases in hydrophobic proline and alanine. [ABSTRACT FROM AUTHOR]

A Z-scheme MoS 2 /Ag 2 S/AgVO x ternary heterostructure was successfully synthesized by a facile hydrothermal method. The as-prepared MoS 2 /Ag 2 S/AgVO x ternary composite has been characterized by electron microscopy, XRD, XPS, UV-Vis DRS, PL, electrochemistry and ESR. TEM characterization revealed that Ag 2 S, Ag nanoparticles and AgVO x nanorods were dispersed homogeneously over the surface of MoS 2 nanosheets The prepared heterojunction showed enhanced photocatalytic performance compared with single MoS 2 and AgVO x. And 6%-MoS 2 /Ag 2 S/AgVO x heterojunction exhibits highest photocatalytic degradation efficiency, which can degrade fuchsine around 75% under visible light within 180 min. The enhanced photocatalytic activity can be attributed to the efficient separation of photogenerated charge carriers, the strong redox ability and enhancement of visible-light absorption derived from the construction of Z-scheme heterostructure. In-situ formed metallic Ag 2 S act as the electron mediator and Ag nanoparticles possess the surface plasmon resonance (SPR) effect. The prepared heterojunction showed decreased photoluminescence and increased photoelectrochemical performance, indicating high separation rate of photoinduced charge carriers. Furthermore, a possible degradation mechanism of fuchsine solution was proposed. And the results of radical trapping experiments indicated that superoxide radicals (∙O 2 -) and holes (h+) play major role during the photocatalytic degradation process. This work demonstrates an interesting Z-scheme photocatalytic system for photocatalysis applications. A distinctive synthesis route and corresponding novel mechanism for ternary Z-Scheme heterostructure MoS 2 /Ag 2 S/AgVO x nanocomposites with enhanced visible light and fast interfacial charges transfer is reported. [Display omitted] • The Z-scheme MoS 2 /Ag 2 S/AgVO x were prepared by a facile hydrothermal method. • The dual effect of MoS 2 facilitated the form of Ag 2 S, and boost theseparation of carriers. • 6%-MoS 2 /Ag 2 S/AgVO x showed the highest photoelectric and photocatalytic activity. • The ESR spectra indicated ·O 2 - and h+ played a major role in photocatalytic reaction. • The enhanced photocatalysis ascribed to construction of Z-scheme heterojunction. [ABSTRACT FROM AUTHOR]

Graphene enhanced WO3 has recently become a promising material for various applications. The understanding of the transfer of charge carriers during the photocatalytic processes remains unclear because of their complexity. In this study, the characteristics of the deposited WO3/graphene layered materials were investigated by Raman spectroscopy, UV–vis spectroscopy, and SEM. According to the results, p-graphene exhibits and enhances the characteristics of the WO3/graphene film. The photocatalytic activities of WO3/graphene layered materials were assessed by the photocatalytic degradation of oxytetracycline antibiotics as irradiated by UV light. Here, a higher current of cyclic voltammetry and a higher resistance of impedance spectra were obtained with the as-grown WO3/graphene directly synthesized on Cu foils under UV light using an electrochemical method, which was different from traditional WO3 catalysts. Thus, it is urgent to explore the underlying mechanism in depth. In this study, a large layered material WO3/graphene was fabricated on a Si substrate using a modified CVD method, and a WO3/graphene device was developed by depositing a gold electrode material and compared with a WO3 device. Due to photo-induced doping effects, the current-voltage test suggested that the photo-resistance is larger than dark-resistance, and the photo-current is less than the dark current based on WO3/graphene layered materials, which are significantly different from the characteristics of the WO3 layered material. A new pathway was developed here to analyze the transfer properties of carriers in the photocatalytic process. [ABSTRACT FROM AUTHOR]