Promotion effect of hydrogen on lean NOx reduction by hydrocarbons over Ag/Al2

Promotional Effect of Titanium on the Catalytic Performance of Anodic Alumina Supported Silver Catalyst for the Selective Reduction of NO with Propene

“…The considerable promotional effect of a small amount of H 2 additive is a promising means to improve the low-temperature activity of Ag/Alumina in the present system (Satokawa et al, 2003(Satokawa et al, , 2007Richter et al, 2004;Shibata et al, 2004). However, the hazard related to the presence of an H 2 tank on-board cannot be neglected.…”

“…According to the results discussed above, in particular the result of Figure 10, it is speculated that besides Ag + and metallic Ag a new type of Ag probably exists in 3. The Satokawa group studied the promotional effect of H 2 additive on the SCR of NO by C 3 H 8 by using Ag/Al 2 O 3 and Ag-MFI (Satokawa et al, 2003(Satokawa et al, , 2007Shibata et al, 2004). On the basis of UV-vis spectroscopic analysis, they proposed that Ag + ions were mainly in existence during C 3 H 8 -SCR in the absence of H 2 , while the addition of hydrogen in the reaction feed reduced Ag + ions to produce moderately agglomerated Ag n δ+ clusters (2 ≤ n ≤ 4).…”

Fuel reforming over Ni-based catalysts coupled with selective catalytic reduction of NOx

“…Using this dual catalyst system, the decrease in NOx conversion at temperatures above 500 K was also pronounced. The mechanism of the H2 effect in HC-SCR over Ag/Al2O3 is still under intense debate, but it has been generally accepted that the presence of H2 promotes partial oxidation of HCs and affects NOx reduction, particularly at low temperatures [24,31,44,45]. The influence of H2 on the activity of Ag/Al2O3 catalysts for NOx reduction has been found to be strongly dependent on the reaction conditions, for example, the concentrations of reductant and H2, ratio of HC/NOx, reaction temperature, space velocity, and so on.…”

“…Although H2 is active for SCR of NOx over precious metal catalysts at low temperatures [21], for Ag/Al2O3 catalysts, H2 is not an efficient reductant [22][23][24]. However, the research of Satokawa [25] noted that a small amount of H2 could significantly improve the activity of Ag/Al2O3 for NOx reduction by C3H8 at low temperatures.…”

Preparation and NO reduction property of apatite-type ALa₉Si₆O₂₆ (A = Li, Na, K) supported Pt catalyst

“…The catalyst was heated to 400°C at 10°C/min and held for 10 min in flowing air at 100 cm 3 /min. Then, the catalyst was purged with He fed at 100 cm 3 /min for 1 min, and then H 2 fed at 100 cm 3 /min for 10 min, and thereafter cooled down to 50°C under He atmosphere. Subsequently the catalyst was held at 50°C under switched feed gases.…”