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In the study, cetyltrimethyl ammonium bromide (CTAB) has been found to have a significant effect on the grain size of zirconia (ZrO 2 ) polycrystalline fibers from a precursor of polyacetylacetonatozirconium (PAZ). A relation between the variation in the grain size of the fibers sintered at 1000 °C for 1 h and CTAB addition has been established by scanning electron microscopy (SEM) and matching the results by a Gaussian Function. The grain size increased firstly and then decreased at an elevated weight percent of CTAB with respect to PAZ. ZrO 2 nucleation at 500 °C and grain growth during thermal treatment between 500 and 1000 °C were investigated by thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The results indicate that the addition of CTAB accelerated the decomposition of PAZ. The enhanced decomposition promoted ZrO 2 nucleation and the removal of residual carbon. While excess CTAB resulted in the increase of residual carbon on grain surface. The general kinetics of the grain growth was evaluated by Arrhenius equation and the results did matched well with the variation in grain size.

In the present work, RF/SiO2 aerogels reinforced by zirconia (ZrO2) were fabricated by a sol–gel process combined with N2-ethanol supercritical drying. The physical properties and microstructures of the aerogels were investigated by uniaxial compression, X-ray diffraction, N2 physico-adsorption, scanning electron microscopy, X-ray photoelectron spectroscopy, and infrared spectrum. The compressive strengths of the aerogels were improved obviously with the addition of ZrO2. The composite aerogels remained amorphous state even the percentage of ZrO2 reached up to 6.77 wt%. The pore sizes of the aerogels with various ZrO2 were hierarchical and the Brunauer-Emmett-Teller surface area increased distinctly with the increase of ZrO2. On the contrary, the aerogel particle sizes decreased as the increase of ZrO2. In our opinion, the enhanced compressive strengths derive from both of the varied pore structures and the decrease of the particle sizes.

Vertically aligned carbon nanotubes (VACNTs) grown on carbon fiber paper (CFP) by plasma enhanced chemical vapor deposition is introduced as a catalyst support material for direct methanol fuel cells (DMFCs). Well dispersed Pt nanoparticles on VACNTs surface are prepared by impregnation-reduction method. The VACNTs on CFP possess well-maintained alignment, large surface area and good electrical conductivity, which leading to the formation of Pt particles with a smaller size and enhance the Pt utilization rate. The structure and nature of resulting Pt/VACNTs/CFP catalysts for methanol oxidation are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscope (SEM). With the aid of VACNTs, well-dispersed Pt catalysts enable the reversibly rapid redox kinetic since electron transport efficiently passes through a one-dimensional pathway, which leads to enhance the catalytic activity and Pt utilization rate. Compared with the Pt/XC-72/CFP electrode, the electrochemical measurements results display that the Pt/VACNTs/CFP catalyst shows much higher electrocatalytic activity and better stability for methanol oxidation. In addition, the oxidation current from 200 to 1200 s decayed more slowly for the Pt/VACNTs/CFP than that of the Pt/XC-72/CFP catalysts, indicating less accumulation of adsorbed CO species. All those results imply that the Pt/VACNTs/CFP has a great potential for applications in DMFCs.

Ordered mesoporous carbons (OMCs) grafted with poly(N-vinylpyrrolidone) (PVP) was prepared through electrochemically induced surface-initiated atom-transfer radical polymerization (SI-eATRP). The introduction of hydrophilic polymer PVP brushes on the surface of OMCs results in the improvement of wettability and a remarkable increase in the specific capacitance. The results of electrochemical performance of OMCs-PVP show good specific capacitance of 253 F g−1, excellent rate performance and good cycling stability with capacitance retention of 89.6% over 5000 cycles. The PVP modification of OMCs via the SI-eATRP method demonstrates an effective way to improve the wettability and electrochemical properties. Keywords: Ordered mesoporous carbons, SI-eATRP, Polymer brushes, Hydrophilic, Supercapacitor