2 research outputs found

    Facile Fabrication of a Superhydrophobic Cu Surface via a Selective Etching of High-Energy Facets

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    The Cu surface with a dual-scale roughness has been prepared via a facile solution-phase etching route by the H<sub>2</sub>O<sub>2</sub>/HCl etchants. The selective etching of the high-energy {110} facets occurs at an ultralow rate of the redox etching reaction. The resultant surface is composed of many polyhedral microprotrusions and nanomastoids on the microprotrusions, exhibiting the binary micro/nanostructures. After hydrophobization, the resultant surface exhibits a water contact angle of 170° and a sliding angle of ∼2.8° for a 5 μL droplet. The combination of the dual-scale roughness and the low surface energy of the adsorbed stearic acid accounts for the superhydrophobicity. Such a superhydrophobic Cu surface has an excellent nonsticking behavior and anticorrosion against electrolyte solution. It also keeps its superhydrophobic ability after a long-time ultrasonication or abrasion test. Our work may shed light on the selective etching of other metal surfaces to create designed dual-scale roughness for superhydrophobicity

    Direct Z‑Scheme TiO<sub>2</sub>/NiS Core–Shell Hybrid Nanofibers with Enhanced Photocatalytic H<sub>2</sub>‑Production Activity

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    Photocatalytic water splitting to generate hydrogen (H<sub>2</sub>) is a sustainable approach for solving the current energy crisis. A novel TiO<sub>2</sub>/NiS core–shell nanohybrid was fabricated where few-layer NiS nanoplates were deposited on TiO<sub>2</sub> skeletons via electrospinning and hydrothermal methods. The NiS nanoplates with a thickness of ca. 28 nm stood vertically and uniformly upon the TiO<sub>2</sub> nanofibers, guaranteeing intimate contact for charge transfer. XPS analysis and DFT calculation imply that the electrons in NiS would transfer to TiO<sub>2</sub> 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 TiO<sub>2</sub> migrated to NiS under UV–visible light irradiation, suggesting that a direct Z-scheme heterojunction was formed in the NiS/TiO<sub>2</sub> hybrid. This direct Z-scheme mechanism greatly promotes the separation of useful electron–hole pairs and fosters efficient H<sub>2</sub> production. The hybrid nanofibers unveiled a high H<sub>2</sub>-production rate of 655 μmol h<sup>–1</sup> g<sup>–1</sup>, which was 14.6-fold of pristine TiO<sub>2</sub> nanofibers. Isotope (<sup>4</sup>D<sub>2</sub>O) tracer test confirmed that H<sub>2</sub> was produced from water, rather than from any H-containing contaminants. This work provides an alternative approach to rationally design and synthesize TiO<sub>2</sub>-based photocatalysts with direct Z-scheme pathways toward high-efficiency photogeneration of H<sub>2</sub>
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