R. Wu

Surface-migration driving uniform amorphous shell on crystalline nanowire: the case of SiC/SiOx core–shell nanowires

Single-crystal SiC nanowires with controlled surface amorphous silicon oxide (SiOx) layers, including bare SiC nanowires, chain-like and cable-like SiC/SiOx nanowires, have been synthesized by a catalyst-assisted chemical vapor reaction approach, and the temperature-dependent morphology evolution of the surface amorphous layers is investigated in detail. Morphological, compositional and structural characterizations indicate that as-synthesized SiC nanowires consist of cubic phase single crystal cores with [111] growth direction and amorphous SiOx shell with varied morphology that can be tuned by temperature. The growth of the SiC nanowires is governed by the vapor–liquid–solid mechanism while the variation of surface SiOx amorphous layers is thought to be controlled by a surface migration process that is mainly dependent on temperature. The results would be helpful to achieve rational modulation of amorphous surface layers on semiconductor nanowires.

Facile Fabrication of Nickel/Heazlewoodite@Carbon Nanosheets and their Superior Catalytic Performance of 4-Nitrophenol Reduction

A facile molten salt method was utilized for the synthesis of carbon anchored nickel/heazlewoodite nanoparticles (Ni/Ni3S2@C nanosheets) with potassium humate as the carbon and sulfur source and NaCl as template. The morphology, particle size and crystallinity of the products were characterized by various techniques containing TEM, FE‐SEM and XRD. Furthermore, the mesoporous Ni/Ni3S2@C own easy accessibility of active sites and high surface area (149.04u2005m2u2009g−1). Thus, the as‐prepared Ni/Ni3S2@C exhibited prominent performance for catalytic reduction of 4‐nitrophenol (4‐NP). Catalytic reduction of other nitrophenols (NPs) were also tested which can prove that the catalyst own selectivity on reduction of NPs. For durability, the property of the catalyst does not decrease obviously after five cycles. More significant correlations concerning effect of activation parameters (Ea=37.21u2005kJu2009mol−1) on 4‐NP reduction were scrutinized and discussed. Hence, we provide a facile method for fabrication of metal/metal sulfide@C which own better dispersity, small dimension and excellent catalytic performance for further studies.