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As a visible-light response semiconductor materials, bismuth vanadate (BiVO4) is extensively applied in photodegradation organic dye field. In this study, we synthesized C3N5 nanosheets and coupled with decahedral BiVO4 to construct a Z-scheme C3N5/BiVO4 heterostructure with close interface contact. By introducing C3N5 into BiVO4, the built Z-scheme transfer pathway provides silky channel for charge carrier migration between different moieties and enables photoexcited electrons and holes accumulated on the surface of BiVO4 and C3N5. The accelerated separation of charge carriers ensures C3N5/BiVO4 heterostructures with a powerful oxidation capacity compared with pure BiVO4. Due to the synergistic effect in Z-scheme heterostructure, the C3N5/BiVO4 demonstrated an improved photodegradation ability of rhodamine B (RhB) and methylene blue (MB) that of bare BiVO4. [ABSTRACT FROM AUTHOR]

Sulfonamides are commonly used antibiotics, but their residues in water bodies pose a potential threat to public health. In this study, we fabricated a 2D/2D composite heterojunction by integrating petal-like flake La2Ce2O7 with stacked slice BiOCl through an in-situ self-assembly method using hydrothermal synthesis. The physicochemical properties of the synthesized materials were systematically characterized. The photocatalytic performance of the composite photocatalyst was found to be superior to that of pure La2Ce2O7 and BiOCl, which can be attributed to the synergistic effect of both high carrier separation and mobility, which ultimately leads to the formation of a 2D/2D heterojunction interface contact between La2Ce2O7 and BiOCl. Notably, the construction of type II heterojunction helps electrons and holes to react on different semiconductors and facilitates the separation of electron–hole pairs. And the hydroxyl radicals and superoxide radicals were captured by electron spin resonance and the strong oxidizing nature of the radicals can effectively break the C–X bond, which is more favorable for the conversion degradation of sulfonamides. A possible photodegradation mechanism based on the catalyst of La2Ce2O7/BiOCl was hypothesized, providing a theoretical basis for preparing 2D/2D heterojunctions with a prominent photocatalytic activity. [ABSTRACT FROM AUTHOR]

A dispersion containing black TiO2 photocatalyst was prepared and sprayed onto the concrete's surface to achieve a black TiO2-based photocatalytic concrete paving eco-block, and its photocatalytic NO removal ratio is approximately 1.7 times as high as that of a white TiO2-based eco-block, resulting from the enhanced optical absorption intensity, abundant oxygen vacancies, and highly produced superoxide anion radicals (˙O2−) of black TiO2. Moreover, the black TiO2-based concrete paving eco-block exhibits significantly enhanced compressive strength and abrasion resistance when using water-glass as a binder, which could satisfy the demand for practical application. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was performed to dynamically track the reactive products and intermediates across the surface of the B-TiO2 photocatalyst in a time sequence to investigate the reaction mechanism. It has been demonstrated that almost no harmful by-products were produced when NO was removed via photocatalysis, and the applicability of the as-prepared eco-blocks was evaluated considering the effects of various reaction conditions. Additionally, a computational fluid dynamics (CFD) model for solar-driven photocatalytic abatement of atmospheric NO in a realistic urban street coating with black TiO2-based photocatalytic concrete paving eco-blocks was constructed and simulated to assess the real-world applicability of the developed approach. Overall, this research may offer fresh perspectives on how to create ecologically acceptable photocatalytic products for the removal of air pollutants using solar light. [ABSTRACT FROM AUTHOR]

It has been rarely reported the morphological control of derivatives of metal‐organic frameworks (MOFs) in hydrothermal conditions for photocatalytic applications. We report here a family of highly efficient composite photocatalysts composed of terephthalic acid/terephthalate (TPA) ligand and TiO2 with various morphologies (e. g. nanoparticles, nanosheets, and nanorods). The composites are synthesized by a simple one‐step hydrothermal method in various solvents (i. e. H2O, HF, H2SO4, HCl, and HNO3) using Ti‐based MOF (MIL‐125(Ti)) as precursor. The formation mechanism of composite materials with different morphological features is discussed. Impressively, the composite of TiO2 nanoparticles/TPA synthesized using H2O as solvent under hydrothermal condition exhibits the highest photocatalytic H2 activity among the studied materials, with a photocatalytic H2 production rate of 6.38 mmol g−1 h−1, which is approximately 7.5‐fold higher than pure TiO2 (Degussa, P25) and prominent apparent quantum efficiency (AQE) of 65 % at 365 nm. Furthermore, the mechanism of boosted photocatalytic H2 production is discussed. [ABSTRACT FROM AUTHOR]

Introducing piezoelectric materials with the built-in electric field caused by mechanical force has been confirmed as an effective strategy to boost the separation efficiency of photoexcited charge carriers that determines the photocatalytic performance. In this study, we introduced Bi4Ti3O12 with superior piezoelectric properties into BiVO4–Bi4V2O10 materials to synthesize a 2D Bi4Ti3O12–BiVO4–Bi4V2O10 photocatalyst via a facile hydrothermal method. Compared with bare BiVO4, the Bi4Ti3O12–BiVO4–Bi4V2O10 piezo-photocatalytic activity towards Cr(VI) removal and oxygen evolution is boosted remarkably under both illumination and ultrasound treatments. The promoted photocatalytic activity can be ascribed to the accelerated photoexcited carrier separation efficiency driven by the polarization electric field and the synergy effect in the heterostructure. This work provides a simple and sustainable strategy for the design and development of piezo-photocatalysts with high photoredox activity capacity. [ABSTRACT FROM AUTHOR]

As one of the high-capacity anodes in lithium-ion batteries (LIBs), silicon oxide (SiOx) has attracted wide attention due to its high theoretical capacity, low cost, and proper working voltage. However, the huge volume change and the intrinsic poor conductivity of SiOx still hinder the practical applications. How to address the issues is the focus of current research. In this work, firstly, hydrogen passivated Si nanosheets (Si6H6) were prepared from Zintl phase CaSi2, then, two-dimensional Ag nanoparticle modified SiOx/C nanocomposite was prepared via a facile complex redox reaction between Si6H6 and AgNO3-aniline complexing agent. In this design, aniline was served as carbon sources, and Si6H6 could be transformed to SiOx by AgNO3 in mild solution condition. The obtained Ag modified SiOx/C (SiOx/C-Ag) electrode exhibited high specific capacity (550 mAh·g−1 at 0.6 A·g−1), superior rate, and cycling performance when served as anode for LIBs. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting for hydrogen (H2) generation is a potential strategy to solve the problem of energy crisis and environmental deterioration. However, powder-like photocatalysts are difficult to recycle, and the agglomeration of particles would affect the photocatalytic activity. Herein, a direct Z-scheme CdS/WO3 composite photocatalyst was fabricated based on carbon cloth through a two-step process. With the support of carbon cloth, photocatalysts tend to grow uniformly for further applications. The experimental results showed that the H2 yield of adding one piece of CdS/WO3 composite material was 17.28 μmol/h, which was 5.5 times as compared to that of pure CdS-loaded carbon cloth material. A cycle experiment was conducted to verify the stability of the as-prepared material and the result demonstrated that the H2 generation performance of CdS/WO3 decreased slightly after 3 cycles. This work provides new ideas for the development of recyclable photocatalysts and has a positive significance for practical applications. [ABSTRACT FROM AUTHOR]

TiO2 nanotube-based photocatalytic concrete paving block was prepared, and its mechanical properties, including compressive strength and abrasion resistance, as well as photocatalytic removal of NO, were investigated. Results indicate that the compressive strength and abrasion resistance of photocatalytic concrete paving block were obviously reinforced by TiO2 nanotubes compared with TiO2 nanoparticles, which might derive from the enhanced binding force between TiO2 nanotubes and calcium–silicate–hydrate (C–S–H) gel derived from the cement hydration. Moreover, the TiO2 nanotube-based photocatalytic concrete paving block shows the best photocatalytic removal of NO among the as-prepared samples, which might result from the enhanced adsorption property for NO gas over TiO2 nanotubes, and little change of NO conversion was found before and after polishing. Overall, TiO2 nanotubes not only contribute to the reinforcement of mechanical properties of the concrete block, but also dedicated to the enhancement of photocatalytic performance for NO purification. [ABSTRACT FROM AUTHOR]

In combination of a facile and scalable solvothermal method and solid-phase reduction reactions, a novel two-dimensional black TiO2 − x nanosheet (TiO2 − x NS) with high specific surface area of 108 m2 g−1 and nearly total solar spectral absorption capability have been successfully prepared. With careful characterizations, the novel TiO2 − x NS showed enhanced electrochemical performance and visible-light photocatalytic activity than those of their white TiO2 nanosheet (TiO2 NS) precursors. The black TiO2 − x NS electrode delivered a reversible specific capacity of 160 mA h g−1 even after cycling at 0.5 C (1 C = 190 mA h g−1) for 300 times, which was significantly higher than the corresponding white TiO2 NS electrode (104 mA h g−1). Meanwhile, the TiO2 − x NS also exhibited enhanced ability of visible-light photocatalytic hydrogen production than that of the white TiO2 NS. It is expected that making white TiO2 NS into black ones is an effective way to design the photocatalysts with visible light response and the anodes with long lifetime and high rate performance in lithium ion batteries. The novel black TiO2 − x NS could find potential applications in the field of environmental management and energy storage and conversion. [ABSTRACT FROM AUTHOR]

A simple calcination approach was performed to synthesize layered K3Ti5NbO14/g-C3N4 (TNCN) composites, in which g-C3N4 was formed both within the interlayers and on the surface of N-K3Ti5NbO14. The photocatalytic activity of samples was evaluated by the visible-light photocatalytic degradation of rhodamine B (RhB). It was found that TNCN composite with a proper mass ratio of N-K3Ti5NbO14 to g-C3N4 exhibited the rapid rate of charge separation and high efficiency of light harvesting due to the synergetic effects of layered heterojunction and N doping, leading to an excellent photocatalytic activity. Especially, the in situ intercalated mono-layered g-C3N4 nanosheets can significantly increase the contact area between K3Ti5NbO14 layers and g-C3N4 nanosheets for efficient charge transfer across the interface, showing the greater effect on the enhanced photocatalytic activity. The active species trapping experiments and ESR measurements were carried out to evaluate the contribution of the active species in this photocatalytic degradation process. It was revealed that both superoxide radicals (·O2−) and holes (h+) are the main active species, while hydroxyl radicals (·OH) made a minor contribution to the photocatalytic degradation of RhB. [ABSTRACT FROM AUTHOR]

Li1.6Mn1.6O4 is a representative ion sieve material that is used to recover lithium from salt brines and bitterns owing to its high lithium ion adsorption capacity reaching 11.9–44 mg g−1. However, manganese dissolution during acid treatment hinders the industrial application of the material. For investigating the mechanism of manganese dissolution, the precursor Li1.6Mn1.6O4 and ion sieve H1.6Mn1.6O4 were prepared and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), chemical content analyses, diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS), and X-ray photoelectron spectroscopy (XPS). The results of XRD, SEM, and FT-IR showed that the bulk phase of Li1.6Mn1.6O4 retained the spinel structure, whereas the lattice diminished during acid treatment. The results of chemical content analyses showed that the bulk phase of Li1.6Mn1.6O4 contained a few trivalent manganese atoms and that the mean valence of manganese in the material increased during acid treatment. DRIFTS and XPS exhibited that the surface of Li1.6Mn1.6O4 was mostly full of tetravalent manganese and retained the spinel structure during acid treatment. In the proposed mechanism of manganese dissolution, an electron of trivalent manganese in the bulk phase transfers to the surface and is captured by tetravalent manganese within the acidic environment. Then, tetravalent manganese is converted to bivalent manganese after acquiring sufficient electrons, and dissolution occurs simultaneously. [ABSTRACT FROM AUTHOR]

Hierarchically structured ZnO hybridized with graphitic carbon nitride (g-CN) is introduced as a new material for non-enzymatic photoelectrochemical sensing of hydrogen peroxide (HO). It is based on the measurement of the decrease in the photocurrent produced by HO which consumes the photoinduced electrons ejected by the ZnO/g-CN composite. The g-CN has a beneficial effect in extending the band width of light absorption of ZnO into the visible region and to promote the separation of the photoinduced carriers. This results in an enhanced photocurrent and high-sensitivity. The ZnO/g-CN composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectrometry, and UV-vis spectrophotometry. Under the optimized condition, the sensor has a linear response to hydrogen peroxide in the 1.3-79.8 nM concentration range, and the detection limit is 0.38 nM. The sensor is sensitive, selective, stable and can be fabricated at low costs. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Herein, we report a one-dimensional (1D) S-doped K3Ti5NbO14@TiO2 (STNT) core-shell heterostructured composite with an enhanced photocatalytic degradation activity under visible light, which was prepared by a simple reassembly-calcination method using thiourea as the S source. The anisotropically shaped rods are favorable for the rapid transport of photogenerated charge carriers. The substitution of Ti4+ by S6+ is primarily incorporated into the lattice of the TiO2 shell so as to create an intra-band-gap state below the conduction band (CB) position, giving rise to Ti−O−S bonds and thus the visible light response. The presence of electron-deficient S atoms is of benefit to the decreased recombination rate of photogenerated electrons and holes by capturing electrons (e−). Meanwhile, a tight close interface between K3Ti5NbO14 and TiO2 was formed to achieve a nano-heterojunction structure, leading to the fostered separation of its interfacial photogenerated electrons and holes. The visible-light-driven photocatalytic degradation of methylene blue (MB) by STNT composites is higher than that by pure K3Ti5NbO14, owing to the synergistic effects of S doping and heterojunction. A possible photocatalytic mechanism was proposed with a reasonable discussion. This work may provide an insight into constructing highly efficient core-shell photocatalysts used toward sustainable environmental remediation and resource shortages. [ABSTRACT FROM AUTHOR]

A novel N-doped K3Ti5NbO14@TiO2 (NTNT) core-shell heterojunction photocatalyst was synthesized by firstly mixing titanium isopropoxide and K3Ti5NbO14 nanobelt, and then calcinating at 500 °C in air using urea as the nitrogen source. The samples were analyzed by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and X-ray photoelectron spectroscopic (XPS) spectra. Anatase TiO2 nanoparticles were closely deposited on the surface of K3Ti5NbO14 nanobelt to form a nanoscale heterojunction structure favorable for the separation of photogenerated charge carriers. Meanwhile, the nitrogen atoms were mainly doped in the crystal lattices of TiO2, resulting in the increased light harvesting ability to visible light region. The photocatalytic performance was evaluated by the degradation of methylene blue (MB) under visible light irradiation. The enhanced photocatalytic activity of NTNT was ascribed to the combined effects of morphology engineering, N doping and the formation of heterojunction. A possible photocatalytic mechanism was proposed based on the experimental results. [ABSTRACT FROM AUTHOR]