Promotional effect of lanthana on the high-temperature thermal stability of Pt/TiO₂sulfur-resistant diesel oxidation catalysts

Abstract

Lanthana in Pt/TiO2–La2O3 catalysts efficiently stabilizes the textural features, and significantly restrains the high-temperature sintering of the Pt/TiO2–La2O3 catalyst particles.

Synthesis of Sulfur-Resistant TiO2-CeO2 Composite and Its Catalytic Performance in the Oxidation of a Soluble Organic Fraction from Diesel Exhaust

“…From the results it can be seen that the sulfur species accumulation is severe on CeO 2 catalyst but is slight on both TiO 2 and TiO 2 -CeO 2 catalysts, which implies that the TiO 2 -based catalysts (TiO 2 and TiO 2 -CeO 2 ) present obviously better sulfur resistibility than the CeO 2 catalyst. Since the non-sulfating material of TiO 2 displays low SO 2 adsorption and hence relieves sulfate generation and exhibits superior sulfur resistibility [32,37]. Furthermore, the introduction of moderate amounts of ceria in TiO 2 has essentially no effect on the naturally excellent sulfur resistibility of TiO 2 .…”

“…Furthermore, the introduction of moderate amounts of ceria in TiO 2 has essentially no effect on the naturally excellent sulfur resistibility of TiO 2 . [37,38]. wt.…”

“…The larger surface area, pore volume and pore size can be advantages to the contacting, transmitting and diffusion of the lube molecules on the catalyst, and hence, be beneficial to the catalytic SOF oxidation activity. Figure 6 shows the XPS spectra of O 1s region of the CeO 2 , TiO 2 and TiO 2 -CeO 2 catalysts, all samples show two XPS peaks, the peak at about 530.1 eV can be assigned to lattice oxygen, and the peak with a binding energy of 532.1 eV is characteristic of surface adsorbed oxygen [37,44]. Due to the superior oxygen storage capacity, the peak of surface adsorbed oxygen of CeO 2 is obviously stronger than the lattice oxygen; the surface adsorbed oxygen ratio is about 55%.…”

“…The simulative 160,000 km vehicle aged sample was obtained by following reference [50] and our previous works [35,37]. Fresh catalyst was placed in a reactor and aged at 670 • C for 15 h and then at 250 • C for 15 h in the gases mixture at flow rate of 800 mL/min: 600 ppm C 3 H 6 , 1500 ppm CO, 200 ppm NO, 50 ppm SO 2 , 5% O 2 , 4% CO 2 , 8% vapor and N 2 balance.…”

“…Sulfur uptake was tested on a thermogravimetric analyzer (TGA) HCT-2 (Henven Instruments, Beijing, China). Consulting the references [38,52] and our previous works [37,53], about 15 mg of catalyst was placed in the sample crucible and pretreated under a 35 mL/min of N 2 flow for 5 h at 300 • C, and then the gas mixture of 43 mL/min SO 2 (0.05 vol. %)-N 2 and 31 mL/min O 2 (15.0 vol.…”