The rational design of electrodes is the key to achieving ultrahigh-power performance in electrochemical energy storage devices. Recently, we have constructed well-organized and integrated three-dimensional (3D) carbon tube (CT) grids (3D-CTGs) using a 3D porous anodic aluminum oxide template-assisted method as electrodes of electrical double-layer capacitors (EDLCs), showing excellent frequency response performance. The unique design warrants fast ion migration channels, excellent electronic conductivity, and good structural stability. This study achieved one of the highest carbon-based ultrahigh-power EDLCs with the 3D-CTG electrodes, resulting in ultrahigh power of 437 and 1708 W·cm⁻³ with aqueous and organic electrolytes, respectively. Capacitors constructed with these electrodes would have important application prospects in the ultrahigh-power output. The rational design and fabrication of the 3D-CTGs electrodes have demonstrated their capability to build capacitors with ultrahigh-power performance and open up new possibilities for applications requiring high-power output.

A facile synthetic approach has been developed to prepare uniform and size-tunable spiky Au@Ag core-shell nanoparticles (NPs) to tailor the localized surface plasmon resonance (LSPR) properties. The gradual assembly of small Au nanocrystals allows the size of spiky Au NPs to be modulated from tens to several hundreds of nanometers by tuning the concentration of initial Au seeds and Au source; and the thickness of the Ag shell can be adjusted with stepwise reduction of Ag(Ⅰ) ions. The LSPR bands of such spiky Au@Ag core-shell NPs resemble those of pure spiky Au NP cores of similar sizes in near-infrared region, and increasing the Ag shell thickness results in a blue shift and broadening of the LSPR band in the near-infrared region. Additionally, the spiky Au@Ag core-shell NPs exhibit improved surface-enhanced Raman scattering (SERS) activity as compared to the bare spiky Au NPs and spherical Ag@Au NPs. This work has offered a facile route to synthesize plasmonic metal NPs with LSPR band in 650 to 800 nm that show strong enhancement of localized electromagnetic field, which provides an effective SERS substrate for SERS imaging and detection in biological fluids and tissues.

The surface topography of noble metal particles is a significant factor in tailoring surface-enhanced Raman scattering (SERS) properties. Here, we present a simple fabrication route to hexagonally arranged arrays of surface-roughened urchinlike Ag hemispheres (Ag-HSs) decorated with Ag nanoparticles (Ag-NPs) for highly active and reproducible SERS substrates. The urchin-like Ag-HS arrays are achieved by sputtering Ag onto the top surface of a highly ordered porous anodic aluminum oxide (AAO) template to form ordered arrays of smooth Ag-HSs and then by electrodepositing Ag-NPs onto the surface of each Ag-HS. Owing to the ordered arrangement of the Ag-HSs and the improved surface roughness, the urchin-like hierarchical Ag-HS arrays can provide sufficient and uniform "hot spots" for reproducible and highly active SERS effects. Using the urchin-like Ag-HS arrays as SERS substrates, 10^-7 M dibutyl phthalate (a member of plasticizers family) and 1.5 × 10^-5 M PCB-77 (one congener of polychlorinated biphenyl, a notorious class of pollutants) are identified, showing promising potential for these substrates in the rapid recognition of organic pollutants.

This paper describes a ZnO-nanotaper array sacrificial templated synthetic approach for the fabrication of the arrays of nanotubes with tube-walls assembled by building-blocks of Ag-nanoplates, Au-nanorods, Pt-nanothorns or Pd-nanopyramids, thus possessing high-density 3D "hot spots" in sub-10-nm gaps of neighboring building blocks with nano-tips, -corners or -edges. Additionally, these hierarchical nanostructure arrays possess high surface area with rich surface chemistry, being beneficial to capturing the analyte. The Ag-nanoplateassembled nanotube arrays can be used as sensitive surface-enhanced Raman scattering (SERS) substrates with good signal uniformity and reproducibility. Using such Ag hierarchical nanostructure arrays as SERS-substrates, not only has 10^-14 M rhodamine 6G been identified, but also 10^-7 M polychlorinated biphenyls (PCBs, a notorious class of persistent organic pollutants) are recognized, and even two congeners of PCBs can be identified in a mixture, showing the potential applications of the materials in SERS-based rapid detection of environmental organic pollutants.

Surface-enhanced Raman spectroscopy (SERS) is a fast analytical technique for trace chemicals; however, it requires the active SERS-substrates to adsorb analytes, thus limiting target species to those with the desired affinity for substrates. Here we present networked polyacrylic acid sodium salt (PAAS) film entrapped Ag-nanocubes (denoted as Ag-nanocubes@PAAS) as an effective SERS-substrate for analytes with and without high affinity. Once the analyte aqueous solution is cast on the dry Ag-nanocubes@PAAS substrate, the bibulous PAAS becomes swollen forcing the Ag-nanocubes loose, while the analytes diffuse in the interstices among the Ag-nanocubes. When dried, the PAAS shrinks and pulls the Ag-nanocubes back to their previous aggregated state, while the PAAS network "detains" the analytes in the small gaps between the Ag-nanocubes for SERS detection. The strategy has been proven effective for not only singleanalytes but also multi-analytes without strong affinity for Ag, showing its potential in SERS-based simultaneous multi-analyte detection of both adsorbable and non-adsorbable pollutants in the environment.

Vertically oriented nanowires (NWs) of single-crystalline wurtzite GaN have been fabricated on a γ-LiAlO₂ (100) substrate coated with a Au layer, via a chemical vapor deposition process at 1000 ℃ using gallium and ammonia as source materials. The GaN NWs grow along the nonpolar [1010] direction with steeply tapering tips, and have triangular cross-sections with widths of 50–100 nm and lengths of up to several microns. The GaN NWs are formed by a vapor–liquid–solid growth mechanism and the tapering tips are attributed to the temperature decrease in the final stage of the synthesis process. The aligned GaN NWs show blue-yellow emission originating from defect levels, residual impurities or surface states of the GaN NWs, and have potential applications in nanotechnology.