The adjustment of the initial synthesis solution pH affects the structure and stability of C16 Co-MCM-41. This pH effect was systematically investigated using N 2 physisorption, TPR, in-situ FTIR, and X-ray absorption spectroscopy. Co-MCM-41 catalysts with the same pore size but greater porosity were synthesized with increasing pH from 10.5 to 12. The distribution of Co ions with respect to being on the pore wall or in the silica wall framework was changed by pH; higher pH produced Co ions mainly distributed just subsurface or in the interior of the silica wall. These pH effects significantly affected the reduction stability of the Co-MCM-41 sample similar to that of the pore radius of curvature effect (Lim et al., J. Phys. Chem. B, 109 (2005) 2285), resulting in stable and size controllable sub-nanometer Co clusters that are useful for catalyst design for specific reactions.

A new organic compound was exploited as a highly stable organic anode for potassium-ion batteries.

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High-quality single-walled carbon nanotubes (SWNT) with high yield were produced by using small-pore Co-MCM-41 catalyst, templated by a C10 surfactant and containing 3 wt % Co. A complete incorporation of Co ions in the silica matrix without formation of surface Co oxides and the contact time of the reaction, in the catalyst synthesis and the SWNT production, respectively, were the most critical factors to be considered. By controlling the reduction temperature and contact time in the reaction, the carbon yield could reach 34 wt % or higher with a selectivity of 96 wt % to SWNT. The metal content after purification of SWNT by base-acid treatments was 0.7 wt %, and the surface area was as high as 1800 m 2 /g. The metal surface occlusion effect by amorphous silica might play a key role in the stabilization of the completely reduced Co metallic clusters in the SWNT synthesis procedure, using small-pore C10 Co-MCM-41.