The NO_x removal rate of the catalysts under different weathering times.

<p>The NO_x removal rate of the catalysts under different weathering times.</p

Direct Z‑Scheme TiO₂/NiS Core–Shell Hybrid Nanofibers with Enhanced Photocatalytic H₂‑Production Activity

Photocatalytic water splitting to generate hydrogen (H₂) is a sustainable approach for solving the current energy crisis. A novel TiO₂/NiS core–shell nanohybrid was fabricated where few-layer NiS nanoplates were deposited on TiO₂ skeletons via electrospinning and hydrothermal methods. The NiS nanoplates with a thickness of ca. 28 nm stood vertically and uniformly upon the TiO₂ nanofibers, guaranteeing intimate contact for charge transfer. XPS analysis and DFT calculation imply that the electrons in NiS would transfer to TiO₂ upon hybridization, which creates a built-in electric field at the interfaces and thus facilitates the separation of useful electron and hole upon photoexcitation. <i>In-situ</i> XPS analysis directly proved that the photoexcited electrons in TiO₂ migrated to NiS under UV–visible light irradiation, suggesting that a direct Z-scheme heterojunction was formed in the NiS/TiO₂ hybrid. This direct Z-scheme mechanism greatly promotes the separation of useful electron–hole pairs and fosters efficient H₂ production. The hybrid nanofibers unveiled a high H₂-production rate of 655 μmol h^–1 g^–1, which was 14.6-fold of pristine TiO₂ nanofibers. Isotope (⁴D₂O) tracer test confirmed that H₂ was produced from water, rather than from any H-containing contaminants. This work provides an alternative approach to rationally design and synthesize TiO₂-based photocatalysts with direct Z-scheme pathways toward high-efficiency photogeneration of H₂

The variation of catalytic activity with different preparation methods at 373K.

<p>The variation of catalytic activity with different preparation methods at 373K.</p

Low-temperature SCR NO_x removal experimental apparatus.

<p>Low-temperature SCR NO_x removal experimental apparatus.</p

Effect of O₂ Concentration on NO_x removal.

<p>Effect of O₂ Concentration on NO_x removal.</p

The variation of NO_x removal rate with different manganese acetate concentration.

<p>The variation of NO_x removal rate with different manganese acetate concentration.</p

Effect of GHSV on NO_x removal.

<p>Effect of GHSV on NO_x removal.</p

Influence of different reaction temperatures on three preparation methods.

<p>Influence of different reaction temperatures on three preparation methods.</p

Rattle-type Carbon–Alumina Core–Shell Spheres: Synthesis and Application for Adsorption of Organic Dyes

Porous micro- and nanostructured materials with desired morphologies and tunable pore sizes are of great interests because of their potential applications in environmental remediation. In this study, novel rattle-type carbon–alumina core–shell spheres were prepared by using glucose and metal salt as precursors via a simple one-pot hydrothermal synthesis followed by calcination. The microstructure, morphology, and chemical composition of the resulting materials were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N₂ adsorption–desorption techniques. These rattle-type spheres are composed of a porous Al₂O₃ shell (thickness ≈ 80 nm) and a solid carbon core (diameter ≈ 200 nm) with variable space between the core and shell. Furthermore, adsorption experiments indicate that the resulting carbon–alumina particles are powerful adsorbents for the removal of Orange-II dye from water with maximum adsorption capacity of ∼210 mg/g. It is envisioned that these rattle-type composite particles with high surface area and large cavities are of particular interest for adsorption of pollutants, separation, and water purification

Few-Layered Graphene-like Boron Nitride: A Highly Efficient Adsorbent for Indoor Formaldehyde Removal

Highly porous boron nitride (BN) composed of a flexible network of hexagonal BN nanosheets was synthesized via thermal treatment of a boric acid/urea mixture. The as-prepared sponge-like BN displayed fast adsorption rates and ultrahigh adsorption capacities for gaseous formaldehyde (HCHO), e.g., 19 mg/g in equilibrium with approximately 20 ppm of HCHO in air, which is an order of magnitude higher than those of other tested materials, including commercial hexagonal BN and various metal oxides. The superb HCHO adsorption performance of the porous BN is mainly due to its large specific surface area (627 m²/g), as well as the abundant surface hydroxyl and amine groups. Moreover, chemisorption can occur on the BN layers and contribute to the high HCHO uptake capacity via Cannizzaro-type disproportionation reactions, during which HCHO is transformed into less toxic formic acid and methanol. This porous BN is a promising adsorbent for indoor HCHO removal and may serve as the support for highly efficient HCHO decomposition catalysts