کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5366993 | 1388359 | 2011 | 11 صفحه PDF | دانلود رایگان |
Nanosilicas (A-50, A-300, A-500)/activated carbon (AC, SBET = 1520 m2/g) composites were prepared using short-term (5 min) mechanochemical activation (MCA) of powder mixtures in a microbreaker. Smaller silica nanoparticles of A-500 (average diameter dav = 5.5 nm) can more easily penetrate into broad mesopores and macropores of AC microparticles than larger nanoparticles of A-50 (dav = 52.4 nm) or A-300 (dav = 8.1 nm). After MCA of silica/AC, nanopores of non-broken AC nanoparticles remained accessible for adsorbed N2 molecules. According to ultra-soft X-ray emission spectra (USXES), MCA of silica/AC caused formation of chemical bonds Si-O-C; however, Si-C and Si-Si bonds were practically not formed. A decrease in intensity of OKα band in respect to CKα band of silica/AC composites with diminishing sizes of silica nanoparticles is due to both changes in the surface structure of particles and penetration of a greater number of silica nanoparticles into broad pores of AC microparticles and restriction of penetration depth of exciting electron beam into the AC particles.
. Silica nanoparticles can penetrate into broad pores of activated carbon microparticles.Highlights⺠Characteristics of nanosilica and activated carbon composites depend on a silica type. ⺠USXE spectra show penetration of silica nanoparticles into broad pores of AC microparticles. ⺠3s-electrons of Si atoms are more sensitive to formation of composites than 2p-electrons of O and C.
Journal: Applied Surface Science - Volume 258, Issue 3, 15 November 2011, Pages 1115-1125