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Heterojunction photocatalytic materials show excellent performance in degrading toxic pollutants. This study investigates the influence of calcination temperature on the performances of floral Bi2O3/TiO2 composite photocatalyst crystal, which was prepared with glycerol, bismuth nitrate, and titanium tetrachloride as the major raw materials via the solvothermal method. XRD, SEM/TEM, BET, Uv-vis, and XPS were employed to analyze the crystal structure, morphology, specific surface area, band gap, and surface chemical structure of the calcined temperature catalysts. The calcination temperature influence on the catalytic performance of composite photocatalysis was tested with rhodamine B (RhB) as the degradation object. The results revealed the high catalytic activity and higher photocatalytic performance of the Bi2O3/TiO2 catalyst. The degradation efficiency of the Bi2O3/TiO2 catalyst to RhB was 97%, 100%, and 91% at 400 °C, 450 °C, and 500 °C calcination temperatures, respectively, in which the peak degradation activity appeared at 450 °C. The characterization results show that the appropriate calcination temperature promoted the crystallization of the Bi2O3/TiO2 catalyst, increased its specific surface area and the active sites of catalytic reaction, and improved the separation efficiency of electrons and holes. [ABSTRACT FROM AUTHOR]

In this study, Z-scheme Cr2O3–Fe3O4/C hetero-nanostructure polyhedra are prepared using the amine-functionalized metal–organic framework NH2-MIL-101(Fe) as the precursor through a simple hydrothermal method and impregnation–calcination route. Systematic characterization was conducted on the phase structure, morphology, optical/electrochemical properties and the photocatalytic performance exhibited by the magnetic Cr2O3–Fe3O4/C samples. As observed from the results, Congo red (CR) degradation rates of the magnetic polyhedron-like Cr2O3–Fe3O4/C hetero-nanostructures under visible light are found to be nearly 1.86 and 1.21 times higher than those achieved by Cr2O3 and Fe3O4/C samples, respectively. Complying with the results achieved by the active specie tests, superoxide radicals could be the major active species in the CR photocatalytic degradation due to graphite carbon with high conductivity. On this basis, a model Z-scheme photogenerated carrier transfer system was developed. In the present paper, an approach for developing and designing Z-scheme hetero-nanostructure photocatalysts for purifying wastewater is presented. [ABSTRACT FROM AUTHOR]

Z-scheme heterostructure photocatalysts for the transfer and separation efficiency of carriers are increasingly popular. CdS nanoparticle decorated three-dimensional (3D) flower-like Zn3(PO4)2 nanostructures were prepared through a simple hydrothermal route and precipitation methods. The CdS/Zn3(PO4)2 heteronanostructures were characterized through X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), UV-visible light spectroscopy (UV-vis), photoluminescence (PL) spectroscopy and photoelectrochemical measurements. The results showed that the three-dimensional flower-like structure of Zn3(PO4)2 composed of two-dimensional nanoplates and CdS/Zn3(PO4)2 heteronanostructures was obtained. The results of the Mott–Schottky measurements and the active species trapping experiments suggested that a Z-scheme system between the CdS nanoparticles and Zn3(PO4)2 nanoplates was formed. Meanwhile, the CdS/Zn3(PO4)2 heteronanostructures exhibited much higher photocatalytic activity for the degradation of MB under visible light, and that of the CdS/Zn3(PO4)2-13 heteronanostructure with excellent photocatalytic stability is nearly 3.04 times higher than that of pure Zn3(PO4)2 nanostructures. [ABSTRACT FROM AUTHOR]

In recent years, environmental wastewater has become an increasingly prominent problem, and photocatalytic degradation is one of the effective means to treat waste pollutants. In this study, glycine was embedded in a tubular carbon nitride material with melamine as the parent by a supramolecular self-assembly strategy to prepare carbon chains implanted tubular graphitic carbon nitride (CTCN). The introduction of carbon chains can reduce the formation of hydrogen bonds, which is beneficial to improve the carrier transport efficiency. It can also adjust the valence band position and has better reduction performance. The thin-walled tubular structure formed by supramolecular self-assembly exposes more active sites and shortens the carrier transport distance due to the size effect, which further improves the carrier separation efficiency. The synergistic effect of the two greatly contributes to the photocatalytic performance of the material. The degradation rate of 0.3% CTCN is 8.1 times higher than that of Bulk CN, and 0.3% CTCN exhibits good stability. This solution is beneficial to optimize some existing wastewater treatment methods and has a role in environmental protection. [Display omitted] • The carbon chain improves molecular polymerization and reduces the formation of hydrogen bonds. • The highly conductive carbon chain facilitates the separation of carriers in carbon nitride. • The thin-walled tubular structure improves the optoelectronic properties of the sample. [ABSTRACT FROM AUTHOR]

The construction of ternary metal oxide to improve photoelectrochemical performances of TiO 2 photocatalysts is the hot topic in environmental and resource applications. Herein, Bi 2 Sn 2 O 7 nanoparticles were deposited on TiO 2 nanotube arrays (TiO 2 NTAs) by the solvothermal technology only by changing reagent concentration. The solar absorption region of TiO 2 NTAs was obviously extended into visible light after Bi 2 Sn 2 O 7 sensitization, and the photoelectric performance was also significantly improved. The high visible light photocurrent density and photovoltage achieved 30.24 μA/cm2 and -0.19 V, and the interface resistance was reduced that benefited the rapid electron transportation. The photocatalytic performances of methyl orange (MO), rhodamine b (RhB), methylene blue (MB) and Cr (VI) removal were enhanced, and 63.76%, 77.34%, 100% and 100% of these pollutants were photoremoved under solar irradiation. Moreover, the construction of direct Z-scheme Bi 2 Sn 2 O 7 /TiO 2 NTAs heterojunction was beneficial to the photoelectron transfer and active radical formation, and the experimental results indicated that •OH and •O 2 - were the decisive species for the dye degradation. The samples also exhibited outstanding photocatalytic water splitting for H 2 evolution, and the high efficiency (306.36 μmol·cm−2·h−1) and stability were confirmed. The excellent photocatalytic performances of the Bi 2 Sn 2 O 7 /TiO 2 NTAs photoelectrodes showed extensive potential applications in environmental pollution and green resource exploitation. [ABSTRACT FROM AUTHOR]

This multifunction CEM-CuO-STA sample demonstrates great potentials in the field of wastewater treatment, oil spill cleanup, and anti-biofouling ability. [Display omitted] Wastewater is typically complicated with spilled oil, water soluble toxic dyes and microorganisms, making it hard to be processed and causing a significant threat to the environmental safety and human health. In this paper, we demonstrate a simple solution immersion method to obtain a multifunctional cellulose-based membrane (CBM) that possesses both superhydrophobicity with a water contact angle of 163° and superior functionalities including self-cleaning, oil–water separation, anti-biofouling, and photocatalytic degradation capabilities. The achievement of separation efficiency (96%), comparatively high flux (141 L·m−2·h−1) and recyclable (7 times) oil/water separation performance is attributed to the robust superhydrophobicity enabled by the synergy of metal oxide (i.e., CuO) nanostructure coating and stearic acid (SA) modification. The superhydrophobic CBM also preferentially adsorbs organic dyes in aqueous solution, e.g., methylene blue (MB), promoting their efficient decomposition (about 70.3% of MB decomposed in 3 h) with high recyclability under UV irradiation. Most remarkably, the CBM exhibits superior anti-biofouling capability and persistently resists the algae adhesion in long duration (over 20 days), as a result of the self-cleaning ability as well as the antimicrobial property of CuO nanoparticles. Our finding here paves the way to use simple, cost-effective, environmentally safe, and reliable method to fabricate multifunctional materials for wastewater treatment in complex environments. [ABSTRACT FROM AUTHOR]

Designing and fabricating the double-capability photocatalysts with the capability of producing hydrogen from the splitting of water and degrading environmental organic pollutants under visible light irradiation are significant in environmental treatment and new energy preparation. As a proof of concept, TiO 2 @ZnFe 2 O 4 heterojunctions with high performance and stability were prepared by a one-step hydrothermal method, in which TiO 2 nanosheets successfully grew on the main body of ZnFe 2 O 4 nanorods. The microstructures and morphologies of the as-produced composites as well as their photocatalytic hydrogen generation rate and photocatalytic degradation performances towards humic acid, florfeniol, tetracyclines, and bisphenol A were investigated. The results indicate that TiO 2 @ZnFe 2 O 4 heterojunctions possessed the higher photocatalytic activities towards hydrogen production and contaminants degradation ability than that of only TiO 2 and ZnFe 2 O 4. Especially, TiO 2 @ZnFe 2 O 4 heterojunctions with the molar ratio of 1:4 have the best activities and manifest good stability. Significant enhancement of visible light absorption and photogenerated charge separation of TiO 2 @ZnFe 2 O 4 were achieved. This work paves a way to construct a low-cost, environment-friendly, recyclable, and non-poisonous photocatalysts for hydrogen generation and the degradation of pollutants. [Display omitted] • TiO 2 @ZnFe 2 O 4 heterojunctions have been prepared and used as double-capability photocatalysts. • The catalyst possessed the enhanced photocatalytic activities for hydrogen production. • The heterojunction can also degrade humic acid, florfeniol, tetracyclines, and bisphenol A. • The heterojunctions can effectively separate the photogenerated electrons and holes. • The formation of the heterojunction can enhance the photocatalytic activity. [ABSTRACT FROM AUTHOR]

TiO 2 nanotube arrays (TiO 2 NTs) were regarded as the outstanding semiconductors for the photocatalytic application in waste water treatment and H 2 generation, and CdS nanoparticles as the visible light sensitizers were traditionally used to enhance the photocatalytic performance. In this paper, CdS–CuS co-sensitizers were deposited on TiO 2 NTs by one-pot hydrothermal method, and the Cu/Cd ratio was changed to adjust the hybrid photocatalyst composition and electron transfer. The photocatalytic data indicated that suitable CdS–CuS composition could effectively enhance the photocatalytic pollutant removal and photocurrent/H 2 evolution and the hybrid photocatalyst also exhibited the high stability by the inhibition of CdS photocorrosion. The p-n heterojunction construction of TiO 2 NTs/CdS–CuS benefited the solar response, photoelectron separation and photocatalytic reaction, and the photocatalytic mechanism and photoelectron transfer were investigated. The p-n heterojunctional photocatalyst is supposed to apply in environmental remediation and new energy development. [ABSTRACT FROM AUTHOR]

The adsorption of reactants is highly correlated with photocatalysis. Improving the adsorption ability of photocatalyst may realize highly efficient removal performance. In this work, Bi 2 MoO 6 and bamboo-derived biochar composite was developed by a facile ball milling method. The adsorption and photodegradation abilities of the composites were evaluated by removing methylene blue (MB), which is a most commonly used aromatic-cationic dye. The maximum adsorption capacity of MB on the optimized 20 % Bi 2 MoO 6 /biochar sample was 160.6 mg/g, and the synergistic adsorption-photocatalytic removal efficiency of MB reached 93.3 % within 30 min, which were superior to Bi 2 MoO 6 (13.3 mg/g, 31.6 %) and biochar (127.7 mg/g, 69.8 %). Compared to Bi 2 MoO 6 , the Bi 2 MoO 6 /biochar composites showed decreased bandgap and enhanced charge separation efficiency. The strong interfacial interactions between Bi 2 MoO 6 and biochar in composites facilitated the photo-induced electrons transfer. Furthermore, the photodegradation efficiency enhanced along with the adsorption efficiency while pH value increased, which further proves the synergy between adsorption and photodegradation. Noticeably, the 20 % Bi 2 MoO 6 /biochar can completely remove MB at pH between 3 and 11. This work proves Bi 2 MoO 6 modified biochar prepared by ball milling is a promising material for synergistic adsorption and photodegradation removal of organic pollutants. [Display omitted] • The optimized 20 % BMO/BC had the maximum adsorption capacity of 160.6 mg/g. • The 20 % BMO/BC showed high MB removal efficiency under light (99.7 %, 60 min). • Removal kinetics were applied to analyze the processes under light or dark. • Synergistic adsorption and photodegradation removal mechanism was elucidated. • Biochar promoted photo-inducted charges transfer in composites. [ABSTRACT FROM AUTHOR]

In this paper, bismuth oxybromide (BiOBr)/biochar composites were synthesized by a facile ball milling method for synergistic adsorption and photodegradation of Reactive red 120 (RR120). The characterizations show that ball milling changed the degree of crystallization, increased the surface area, and promoted the charge transfer ability of biochar. The 70% BiOBr/BC composite showed the best removal efficiency for RR120 removal with or without light illumination, which proves its enhanced removal ability by adsorption and photodegradation. The biochar is served as a support of BiOBr for preventing its aggregation and a transporter of charges for promoting the separation of photo-induced carriers in composites. BiOBr can release the adsorption sites on the surface of composites by degradation, which facilitated the RR120 removal and regenerated the photocatalyst for reusing. The strong interactions between BiOBr and biochar in composites resulted from ball milling were beneficial for the charge transfer and synergistic removal of adsorption and degradation. Findings of this work indicate that ball milling method is an effective method to prepare highly efficient biochar-based composites for RR120 removal through synergistic adsorption and photodegradation. [Display omitted] • BiOBr/biochar composites were firstly synthesized by ball milling method. • Biochar increased the surface area and promoted charge transfer in composites. • There were strong interactions between BiOBr and biochar after ball milling. • Synergy between adsorption and photodegradation in BiOBr/biochar is elucidated. [ABSTRACT FROM AUTHOR]

A CM-MnO 2 -STA sample for oil/water separation, photocatalytic degradation and anti-biofouling property was obtained via MnO 2 micro/nano structure and subsequent modification of STA. This multifunction CM-MnO 2 -STA sample demonstrates great potentials in the field of wastewater treatment, oil spill cleanup, and anti-biofouling ability. [Display omitted] • A CM-MnO 2 -STA sample was obtained by MnO 2 micro/nano structure and STA. • This sample showed physical/chemical/mechanical stability in harsh environment. • This sample showed superior oil–water separation efficiency. • This sample showed great photocatalytic degradation activity. • This sample exhabited strong anti-biofouling adhesion potential. Flexible multiple functional cellulose-based membrane (CM) for oil/water separation, anti-microbial and photodegradation are in great demand in marine wastewater treatment due to its' effective and ecologically benign. Based on this requirement, MnO 2 micro/nanoparticles were in situ deposited on CM sample surface followed by decoration of stearic acid (STA) for very effective oil/water separation, anti-fouling, and dye photodegradation triggered by visible light. The results demonstrated that this as-prepared CM sample showed superhydrophobicity with a water contact angle of 162 ± 2° and superoleophilicity with an oil contact angle of 0°. It also demonstrated exceptional high stability in hostile environments (acid and alkali solution, high temperature, wear resistance, underwater writing, self-cleaning) and a 2.6% increase in tensile strength. In addition, it can successfully separate emulsified oils from typical oil-in-water emulsions with good separation efficiency all over 98% and comparatively high flux (145.8 L·m−2·h−1). After 8 cycles, the separation efficiency of the n-hexane/water emulsion is still over 98%. Moreover, over 98% of MB was degraded by using superhydrophobic CM sample, indicating strong photocatalytic activity. Meanwhile, in the maritime environment, this biomimetic sample decreased the adherence of green algae by more than 95%, demonstrating strong anti-biofouling adhesion potential. It indicates that this cost-effective, scalable, environmental friendly, and efficient methodology presented superhydrophobic CM sample has the potential to promote the widespread development of multipurpose superwetting materials, with enticing potential for the treatment of complex oily wastewater. [ABSTRACT FROM AUTHOR]

• The N, F codoping in TiO 2 NTs were carried out by solvothermal-assisted annealing treatment. • The codoped photoelectrode displayed the attractive photocatalytic performance. • The preparation and doping mechanism were explored. [Display omitted] By the exploitation of doping in semiconductor photocatalysts, the energy band structure adjustment would induce the improvement of solar absorption and photochemical performance. Here, we investigated the N/F codoped TiO 2 nanotube arrays (TiO 2 NTs) by tuning the preparation operation sequence of solvothermal doping and annealing treatment. The optimized Sample 1 prepared by the first solvothermal doping in ethanol and then annealing exhibited the outstanding solar absorption, low electron-hole recombination and photoelectrochemical performances. The excellent photocatalytic performances in photocurrent/H 2 generation and pollutant removal were discussed and analyzed in detail. Furthermore, we explained the mechanism of N/F codoping for improved photocatalytic performances. The work gives a referable template for improved photocatalytic application fields of TiO 2 in environment and energy. [ABSTRACT FROM AUTHOR]