A facile and green route was introduced to synthesize Au nanoparticles immobilized on halloysite nanotubes (AuNPs/HNTs) used for surface-enhanced Raman scattering substrates. The naturally occurring HNTs were firstly functionalized with a large amount of -NH(2) groups by N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane (AEAPTES), which possesses one lone electron pair and will "anchor" Au ions to form a chelate complex. Then, with the addition of tea polyphenols (TP), the Au ions were reduced on the surface of the previously formed Au-NH(2) chelate complex to form AuNPs. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) observations indicate that a large amount of AuNPs were synthesized on HNTs. The AuNPs are irregularly spherical and densely dispersed on HNTs and the diameter of the nanoparticles varies from 20 to 40 nm. The interactions between AuNPs and -NH(2) groups were verified by X-ray photoelectron spectroscopy (XPS) and the results showed that the functional groups can "anchor" AuNPs through the chelating effect. The as-prepared AuNPs/HNTs nanomaterials with several nanometers gaps among nanoparticles were used as a unique surface-enhanced Raman scattering substrate, which possessed strong and distinctive Raman signals for R6G, indicating the remarkable enhancement effect of the AuNPs/HNTs.

Based on first-principles calculations, we demonstrated that a GeSe/SnSe heterostructure has a type-II band alignment and a direct band gap. The predicted photoelectric conversion efficiency (PCE) for the GeSe/SnSe heterostructure reaches 21.47%.

The green natural compounds, tea polyphenols (TP), were introduced to synthesize well-dispersed Au nanoparticles (AuNPs) in polyacrylonitrile (PAN) nanofibers by combining an in situ reduction approach and electrospinning technique. The AuNPs were firstly synthesized in aqueous solution to test the reducibility of the TP. Then, the well-dispersed AuNPs in PAN nanofibers were obtained by an in situ reduction approach and electrospinning technique. Fourier transform infrared spectroscopy (FTIR) was utilized to confirm the reducibility of TP. The transmission electron microscopy (TEM) and the ultraviolet-visible spectroscopy (UV-Vis) demonstrated the formation of AuNPs and their morphology. Surprisingly, compared with the AuNPs in aqueous solution, the AuNPs in PAN nanofibers via electrospinning were much smaller and well-dispersed and it was attributed to the stabilization effect of PAN through the chelating effect between gold and cyano groups. Apart from the reducibility effect, TP also served as a stabilizer together with PAN to prevent the aggregation of AuNPs effectively, which were testified by X-ray photoelectron spectroscopy (XPS) results.

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This communication demonstrates a novel strategy for the selective growth of Au nanograins (AuNGs) on specific positions (tips, edges and facets) of Cu(2)O octahedrons to form Cu(2)O-Au hierarchical heterostructures. The surface energy distribution of the octahedrons generally follows the order of γ((facets)) < γ((edges)) < γ((tips)) and leads to the preferential growth and evolution of the heterostructures. These novel Cu(2)O-Au hierarchical heterostructures show fascinating degradations of methylene blue (MB), due to the suppressed electron/hole recombination phenomena and the highly efficient light harvesting.