Promotional effects and mechanism of second cations on activity and stability of Co-MOR for nitrous oxide decomposition: UV–Vis spectroscopy and EXAFS analysis

Influence of composition (Pd) In-, Co-containing aluminia- and zirconia-based catalysts on simultaneous reduction of nitrogen(I, II) oxides by CO

“…Binary catalysts exhibit higher activity in the investigated process, which depends on the sequence of active components introduction (cobalt and indium oxides), the nature of the catalyst carrier, acidic properties of the surface. The high catalytic activity of In-Co / Al 2 O 3 takes place may be the positive effect of In 2 O 3 on the stabilization of cobalt in the state of Co(II) in the composition of highly dispersed cobalt oxide clusters [1]. This catalyst also characterized by greater moisture resistance: 90-98% conversion of reagents is achieved at temperatures of 450-500 °C in reaction mixtures with Н 2 О ( fig.…”

Simultaneous Selective Catalytic Reduction of NO and N2O by NH3 over Fe-Zeolite Catalysts

“…Besides, using a microreactor, the reaction rate (r) for NH 3 -SCR could be calculated by following an apparent first-order reaction. 12,37 r F x W ln( 1)…”

“…To avoid the collapse of the SAPO-34 framework in the wet ion-exchange process, the Fe-SAPO-34 catalyst was prepared by the solid-state ion-exchange method. 12 3 g of H-SAPO-34 (Si/Al = 25, purchased from Nankai University Catalyst Co., Ltd.) zeolite was mechanically mixed with 0.3 g of FeCl 2 •4H 2 O salt for 30 min. Then, the catalyst was obtained by calcination at 550 °C for 4 h.…”

“…The Fe (II) ions in the zeolites were first oxidized by N 2 O to the Fe (III) ion; later, the desorption of O 2 over the Fe-zeolites resulted in the reduction of Fe (III) ions. Zhang et al 12 showed that both monomeric Fe (III) ions and small oligomeric Fe x O y species were considered as active Fe species for N 2 O decomposition on the Fe/SAPO-34 catalysts, and the aggregated FeO x particles in zeolite supports exhibited poor activity for N 2 O decomposition. These studies indicated that, in both NH 3 -SCR and N 2 O decomposition, the catalytic performance of Fe-zeolites might be greatly influenced by the distributions of iron cations.…”

“…Despite the well-developed Fe-zeolites for NH 3 -SCR and N 2 O decomposition, the synergetic reactions of NO x and N 2 O were not fully explored yet. It was reported that the N 2 O decomposition was notably promoted under the SCR condition in the presence of reductant, such as NH 3 and CO . However, the catalytic activity in CO-SCR for NO or N 2 O removal was limited because of the insufficient reducing ability, particularly in the presence of O 2 .…”