Preparation and catalytic performance of Ag, Au, Pd or Pt nanoparticles supported on 3DOM CeO2–Al2O3 for toluene oxidation

Abstract

Three-dimensionally ordered macro-/mesoporous 26.9 wt% CeO 2 −Al 2 O 3 (denoted as 3DOM 26.9CeO 2 −Al 2 O 3 )-supported noble metal nanocatalysts (xM/3DOM 26.9CeO 2 −Al 2 O 3 , x = 0.27−0.81 wt%; M = Au, Ag, Pd, and Pt) were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction methods, respectively. It is shown that the xM/3DOM 26.9CeO 2 −Al 2 O 3 samples displayed a high-quality 3DOM architecture with a bimodal pore (macropore size = 180-200 nm and mesopore size = 4-6 nm) structure and a surface area of 102−108 m 2 /g, with the noble metal nanoparticles (3-4 nm in size) being highly dispersed on the 3DOM 26.9CeO 2 −Al 2 O 3 surface. The 0.27Pt/3DOM 26.9CeO 2 −Al 2 O 3 sample performed the best (T 90% = 198 o C at space velocity = 20,000 mL/(g h)) for toluene oxidation. The addition of moisture to the feedstock induced a positive effect on catalytic activity. The apparent activation energies obtained over the xM/3DOM 26.9CeO 2 −Al 2 O 3 samples were in the range of 46-100 kJ/mol, with the 0.27Pt/3DOM 26.9CeO 2 −Al 2 O 3 sample possessing the lowest apparent activation energy. It is concluded that the good catalytic performance of 0.27Pt/3DOM 26.9CeO 2 −Al 2 O 3 was associated with its higher adsorbed oxygen species concentration, better low-temperature reducibility, and stronger interaction between Pt and 3DOM 26.9CeO 2 −Al 2 O 3 as well as the unique bimodal porous structure.

Three‐Dimensionally Hierarchical Pt/C Nanocomposite with Ultra‐High Dispersion of Pt Nanoparticles as a Highly Efficient Catalyst for Chemoselective Cinnamaldehyde Hydrogenation

“…Thee xistence of ad istinct H2 type hysteresis loop at medium P/P 0 (0.2-0.8) andn oc lear adsorption plateau at P/P 0 % 1.0 imply the presence of huge amounts of mesopores and macropores, respectively. [45][46][47][48] As shown in Figure 2b,t he Pt/3DHPC possesses aw ell-developed pore system with detectable sizes from 0.4 and 400 nm. The micropores with sizes of 0.4-2 nm and multiple peaks at 0.62, 0.86, 1.25, 1.46, and 1.76 nm are possibly generated from the carbonization of the RF resol, whereas the mesopores with ab road distribution of 2-50 nm and am aximum peak at 3.7 nm is contributed from the aggregation of cross-linked carbon particles andt he templating functiono fF 127.…”

Ag/CeO2 Composites for Catalytic Abatement of CO, Soot and VOCs

“…Of particular interest is the approach to locate the Ag/CeO 2 composition on the inert support, which is usually represented by alumina or silica [144,145]. Thus, H. Yang et al [144] used 3DOM CeO 2 -Al 2 O 3 as a support for Ag catalysts for toluene oxidation. This support was prepared using the Pluronic F127 (EO 106 PO 70 EO 106 ) and PMMA as soft and hard templates, respectively.…”

“…Spillover effect was proposed to reduce the regeneration ability of active oxygen, when Ag loading is high, which was connected with lower concentration of surface oxygen vacancies. Of particular interest is the approach to locate the Ag/CeO2 composition on the inert support, which is usually represented by alumina or silica [144,145]. Thus, H. Yang et al [144] used 3DOM CeO2-Al2O3 as a support for Ag catalysts for toluene oxidation.…”

Metal Nanoparticles Syntheses on Ionic Liquids Functionalized Mesoporous Silica SBA‐15

“…The choice of active metal oxides as supports for metal NPs have improved activity in organic transformations. [8][9][10][11][12][13] For inert supports such as carbon and silica, the activity seems to solely depend on the particle size and among them, SBA-15 offers many advantages as suitable "host" since it possesses unique physical properties such as uniform pore size distribution, large pore size and surface area, and easy surface modification. However, it has a drawback when large NPs are formed inside pores, causing pore-blocking effect due to the pore size limitation.…”