Nitrogen Adsorption and Characteristics of Iron, Cobalt, and Nickel Oxides Impregnated on SBA-15 Mesoporous Silica

Abstract

Hexagonal SBA-15 mesoporous material was used as a catalytic template for impregnation, with the transition metals Fe, Co, and Ni as catalysts for chemical transformation. Nitrogen adsorption/desorption isotherms, scanning electron microscopy, and transmission electron microscopy were conducted to better understand the physicochemical properties of the metal oxide-impregnated SBA-15. The specific surface area of the original SBA-15 was approximately 680 m2/g, and the abundances of the catalysts impregnated ranged from 2 to 8%, corresponding to specific surface areas of 560–470 m2/g for Fe-SBA-15, 440–340 m2/g for Ni-SBA-15, and 410–340 m2/g for Co-SBA-15. The increase in impregnated metal loadings filled the pores and collapsed the silica walls during the metal oxides impregnation on SBA-15 and calcination procedures, resulting in a decrease in the specific surface area and pore volume of the templates. The results showed that the order of nitrogen adsorbed was SBA-15 > Fe-SBA-15 > Ni-SBA-15 > Co-SBA-15 when the metal loading was 5%. In addition, the metal oxides on SBA-15 increased the wall thickness compared with raw SBA-15. Based on the XRD spectrum analysis, Fe2O3, Co3O4, and NiO were the stable crystals on the Fe-SBA-15, Co-SBA-15, and Ni-SBA-15, respectively. The sequence of the average grain size of metal oxides on SBA-15 was Co-SBA-15 > Fe-SBA-15 > Ni-SBA-15, according to XRD spectra and Scherrer’s equation. Isopropanol could be decomposed by metal oxide-impregnated SBA-15 to form carbon filament materials. Therefore, these materials have the potential to be employed for pollutant removal, catalytic reactions for organic solvent and bio-oil/biomass reforming, and recycling waste into high-value materials.

Study on methylene blue adsorption using cashew nut shell-based activated carbon

“…Nitrogen adsorption and desorption measurements were used to characterize the porous structure of CNS AC. The hysteresis loop in the relative pressure range of 0.3-1.0 (Figure 2) is a sign of Type IV isotherm according to the IUPAC classification, indicating the presence of mesopores in the CNS AC structure [24,25]. This is further supported by the BJH pore size distribution (inset in Figure 2), which shows that the pore diameters are less than 4 nm, with micropores (< 2 nm) being the dominant pore type.…”

Microenvironment Modulation of Single-Atom Ru in ZrSBA-15 for CO2 Hydrogenation to Formic Acid

“…SBA-15 featuring a large surface area, abundant mesoporous channels, and remarkable hydrothermal stability has drawn tremendous attention as an efficient catalytic material or supporting matrices for active components. − In addition, the fascination of SBA-15 also comes from the easy modification because of the existence of plentiful surface Si–OH groups. , Especially, the platelet-like ZrSBA-15 with short mesoporous channels as the support benefit to improve the catalytic performance compared with traditional SBA-15 . For example, Zhai et al reported that the phosphotungstic acid catalyst supported by a platelet-like ZrSBA-15 demonstrated highly improved catalytic activity for the selective oxidation of benzyl alcohol .…”