The catalytic oxidation of toluene has been investigated using a series of Pt/SBA-15 and Pt/SiO 2 catalysts, and the Pt/SBA-15 catalyst exhibits significantly higher catalytic activity for the oxidation of toluene than the Pt/SiO 2 catalysts. The SBA-15-supported Pt nanoparticles possess the ability to strongly dissociate toluene to benzene, hydrocarbon fragments (CH x ), and H 2 at low temperatures, but the Pt/SiO 2 catalysts are nonreactive toward the decomposition of toluene. The products resulting from the dissociation of toluene were easily oxidized by oxygen, thereby positively affecting the conversion rate of toluene oxidation on Pt/ SBA-15. Temperature-programmed desorption measurements clearly indicate that the dissociation reaction mainly consists of breakage of the C−C bonds between the phenyl and methyl groups. Combined density functional theory (DFT) calculations and DRIFT spectroscopy are carried out to investigate the stretching frequency of CO adsorbed on the defect sites of various Pt clusters, suggesting that the subnanosized Pt particles (icosahedron cluster) and/or Pt single atom may be formed in the structure of SBA-15. Pt sites associated with low coordination and subnanoscale Pt particles and/or single Pt atoms in the SBA-15 support can facilitate toluene adsorption and induce strong dissociation.

In this paper, we have shown that Cu/TiO(2) catalysts are highly active in CO oxidation. For instance, a 3.4% Cu/TiO(2) catalyst exhibits a higher turnover rate for the effective removal of CO in air than 3-5% Pt/TiO(2) and 20% Cu/ZnO/Al(2)O(3) catalysts. A small amount of Cu(+) species is formed during the calcination treatment at 225 °C, which is the main active phase for the CO oxidation. However, it is proposed that some highly dispersed CuO can also form in the TiO(2) lattice during the calcination treatment. Furthermore, a strong electron interaction between Cu(2+) in highly dispersed CuO and Ti(3+) on rutile TiO(2) (Cu(2+)+Ti(3+)→Cu(+)+Ti(4+)) has been shown to occur. Overall, the reduction of Cu(+) is a major factor that contributes to the reaction rate of the CO oxidation.

In this work we developed a one-step process for synthesizing carboxylic-functionalized carbon nanofibers (CNFs)-encapsulated Ni magnetic nanoparticles (Ni@CNFs) that exhibit an excellent magnetic response and a large content of hydrophilic carboxylate groups with a negative charge (RCOO(-)) on the carbon surface. The carbon-encapsulated magnetic Ni nanoparticles could be rapidly separated from water, and they showed high efficiency for adsorption of the antibiotic sulfamethoxazole (SMX) in aqueous solution. The adsorption of SMX on Ni@CNFs as a function of pH was investigated, and the greatest adsorption occurred at pH 7.0. The adsorption isotherms for SMX on Ni@CNFs depended on different pH values. A Monte Carlo simulation was used to probe the relationship between molecular conformation and π-π interaction. The high adsorption of SMX on Ni@CNFs at pH 7.0 could be ascribed to deprotonated SMX being easily converted to a planar-like conformation, thereby resulting in the formation of π rings that were approximately parallel to the graphite surface and that enhanced strong π-π interaction. Electrostatic and π-π interactions both contributed to deprotonated SMX adsorption at pH 7.0, and they influenced the adsorption isotherm toward the Freundlich model. However, in weakly acidic environments (pH 2.0 and 4.0), the electrostatic interaction alone could induce an adsorption pattern that was similar to the Langmuir model.