Development of monolithic catalysts with low noble metal content for diesel vehicle emission control

Abstract

The chemical composition of the catalyst containing Mn-Al-O and Pt has been developed on the basis of the synergetic effect of Pt and manganese oxides observed in the HC and CO oxidation reactions. This effect allows decreasing the Pt loading to 0.70 g/L in the catalytic systems of diesel engine exhaust gases and provides high activity in low temperature oxidation of light and heavy hydrocarbons, and high thermal stability. It has been found that the catalytic activity of Pt-Mn-Al monolithic catalysts in butane oxidation and DIESEL tests depends on the Pt precursor and Pt loading. At similar Pt loadings (1.06 g/L), the catalytic activity increases in the order H 2 PtCl 6 $ H 2 [Pt(OH) 6 ] < Pt(NO 2 ) 2 (NH 3 ) 2. When one Pt precursor is used, the catalytic performance improves with Pt loading increase from 0 to 1.06 g/L, and being nearly constant at higher Pt loading (2.65 g/L).

Catalytic NOx Abatement Systems for Mobile Sources: From Three-Way to Lean Burn after-Treatment Technologies

“…375 Subsequent improvements by combining Pt(Pd) with manganese oxide were also reported. 376 MnO x supported on cordierite monolith wash-coated with γ-Al 2 O 3 and MnO x supported on granulated γ-Al 2 O 3 and subsequently modified by doping with 0.1-1.0 wt % Pt or Pd showed a very good efficiency in methane oxidation. However, the extent of the synergetic effect strongly depends on the nature of the platinum precursor.…”

Catalytic Combustion of Methane over Pt–Ce Oxides under Scarce Oxygen Condition

“…However, each one of them is suitable for different applications. Pd-based catalysts with changeable valences are recognized as the most active catalysts for the oxidation of methane under lean-burn conditions, where Pd is generally considered in an oxide state 8 and is more active than Pt, 9−11 whereas metallic state is generally considered to be the active phase for methane oxidation by Pt-based catalysts. 12 Thus, a Pt-based catalyst is preferable at methane rich conditions like reforming and partial oxidation of methane.…”

Manganese Oxide-Based Catalysts for Soot Oxidation: A Review on the Recent Advances and Future Directions

“…In the foreseen future, internal combustion engines (ICEs) are likely to play a significant role, especially in the heavy transport, marine, and aviation sectors, considering their notable benefits in power density, efficiency, and reliability. Nevertheless, the applications of ICEs running with fossil fuels also bring out unwanted greenhouse gases and harmful engine-out emissions such as nitrogen oxides (NO x ) and soot particle emissions. − Especially, the nanosized soot (those with a size below 2.5, commonly called PM 2.5 ) can be quite carcinogenic, as they could penetrate into human lungs and blood circulatory systems, causing serious health concerns . Recent statistical data have suggested a strong correlation between air PM pollution and premature deaths .…”