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Carbon nanotubes can be functionalized by oxidation of HNO 3 or H 2 SO 4 -HNO 3 . The latter shows a higher capability in producing a high density of surface functional groups. These groups can act as specific nucleation sites for a well-dispersed deposition of Pt clusters on the surface of carbon nanotubes. These modified carbon nanotube materials were investigated by TEM, XPS, and DRIFT. A deposition mechanism is tentatively proposed and discussed.

It is challenging to introduce pendent sulfonic acid groups into modularly built crystalline porous frameworks for intrinsic proton conduction. Herein, we report the mechanoassisted synthesis of two sulfonated covalent organic frameworks (COFs) possessing one-dimensional nanoporous channels decorated with pendent sulfonic acid groups. These COFs exhibit high intrinsic proton conductivity as high as 3.96 × 10(-2) S cm(-1) with long-term stability at ambient temperature and 97% relative humidity (RH). In addition, they were blended with nonconductive polyvinylidene fluoride (PVDF) affording a series of mixed-matrix membranes (MMMs) with proton conductivity up to 1.58 × 10(-2) S cm(-1) and low activation energy of 0.21 eV suggesting the Grotthuss mechanism for proton conduction. Our study has demonstrated the high intrinsic proton conductivity of COFs shedding lights on their wide applications in proton exchange membranes.

Thermally stable Au single-atoms supported by monolayered CuO grown at Cu(110) have been successfully prepared. The charge transfer from the CuO support to single Au atoms is confirmed to play a key role in tuning the activity for CO oxidation. Initially, the negatively charged Au single-atom is active for CO oxidation with its adjacent lattice O atom depleted to generate an O vacancy in the CuO monolayer. Afterward, the Au single-atom is neutralized, preventing further CO reaction. The produced O vacancy can be healed by exposure to O at 400 K and accordingly the reaction activity is restored.

Deposition technology of transparent conducting oxide (TCO) thin films is critical for high performance of optoelectronic devices. Solution-based fabrication methods can result in substantial cost reduction and enable broad applicability of the TCO thin films. Here we report a simple and highly effective solution process to fabricate indium-tin oxide (ITO) thin films with high uniformity, reproducibility, and scalability. The ITO films are highly transparent (90.2%) and conductive (ρ = 7.2 × 10(-4) Ω·cm) with the highest figure of merit (1.19 × 10(-2) Ω(-1)) among all the solution-processed ITO films reported to date. The high transparency and figure of merit, low sheet resistance (30 Ω/sq), and roughness (1.14 nm) are comparable with the benchmark properties of dc sputtering and can meet the requirements for most practical applications.

Optical limiting effects in multiwalled carbon nanotubes have been observed in the visible and infrared spectral regions with nanosecond laser pulses. The multiwalled carbon nanotubes investigated include those suspended in distilled water and embedded in polymethyl methacrylate films. Among all the samples measured, the limiting performance of the carbon nanotube suspension is the best with the limiting threshold determined to be ∼1, 5, and 13 J/cm2 at 532, 700, and 1064 nm, respectively. The possible mechanism for the observed effects is discussed.

Cu-, Eu-, or Mn-doped ZnS nanocrystalline phosphors were prepared at room temperature using a chemical synthesis method. Transmission electron microscopy observation shows that the size of the ZnS clusters is in the 3–18 nm range. New luminescence characteristics such as strong and stable visible-light emissions with different colors were observed from the doped ZnS nanocrystals at room temperature. These results strongly suggest that impurities, especially transition metals and rare-earth metals-activated ZnS nanoclusters form a new class of luminescent materials.

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