Structure of carbonized mesoporous silica gel/CVD-titania

Laser oxidative pyrolysis synthesis and annealing of TiO2 nanoparticles embedded in carbon–silica shells/matrix

“…One such material was the carbonized mesoporous silica gel/CVDtitania composites with different C and TiO 2 concentrations [26]. The mechanochemical intercalation technique was used to obtain nanoporous graphite-derived carbon/TiO 2 -SiO 2 composites from C 16 H 33 N(CH 3 ) 3 Br (CTAB) pre-intercalated graphite oxide, TEOS and TTIP which was successfully tested for phenol adsorption and degradation under UV sterilizing light [27].…”

Effect of Carbon Deposits on the Structure of Hybrid C/TiO2/SiO2 Adsorbents

“…However, with the pyrocarbon/fumed silica reduction product, the value of S BET (and of V p ) is smaller (Tables 1 and 2) than those for the pyrocarbon/silica gel (Tables 3 and 4, Figure 1; see also Gun'ko et al 2000c,d,h;Leboda et al 2000a). Typically, at high C C values, the pyrocarbon formed on the silica surface (which does not exhibit a marked catalytic activity in the pyrolysis process) consists of relatively large and dense spherical particles possessing a low or negligible intrinsic porosity (Fenelonov 1995).…”

Structural and Energetic Nonuniformities of Pyrocarbon–Mineral Adsorbents

“…4b, MCA, 1h) enhance the effective pore volume (V p ≈ 1.10-1.14 cm 3 /g filled by nitrogen at p/ p 0 ≈ 0.99) by approximately two times; however, MCA during 24 h reduces the effective pore volume to 0.61 cm 3 /g close to V p (0.67 cm 3 /g) for initial silica powder (19b). For some carbosils (AS 3 and CVDtitania/fumed silica TS 2 , TS 5 , TS 17 ) at C C = 17-28 wt.% (Fig. 1, Table 5), appearance of pyrocarbon deposits formed on the outer surfaces of aggregates of primary particles during pyrolysis of cyclohexene results in an enhancement of a portion of V emp accessible for adsorbed nitrogen at p/p 0 ≈ 0.99 due to formation of tighter agglomerates similar to those after MCA of silica powder.…”

“…1) are lower than those for C/fumed silica at close values of C C ; i.e., pyrocarbon in C/TS (cyclohexene carbonization) is more dispersed than that in C/fumed silica (CH 2 Cl 2 pyrolysis). For C/silica gel and C/CVD − TiO 2 /silica gel, these changes are larger due to the internal porosity of the silica gel matrix, crystalline and morphological features of CVD-titania influencing pyrolysis (2,5,16,17). For instance, segregated and denser CVD-TiO 2 prepared on the silica gel surfaces at 873 K (K68 sample with rutile + anatase on silica gel KSK-2) (2) causes lower changes in S BET and V p than less dense titania (K28 with grafted anatase more active in redox reactions than rutile) prepared at a lower temperature (473 K) ( Table 4).…”

“…Carbon-oxide samples were synthesized using pyrolysis of cyclohexene at the silica gel (K03) and CVD-TSG (K282, K682) surfaces at a constant partial pressure 51.3 mm Hg in a flow reactor under isothermal conditions and gravimetric control at 973 K for 5 h (Table 4) (2,17).…”