Automotive Emission Control Catalysts

Abstract

Emission control catalysts constitute an essential part of today’s vehicles powered by internal combustion engines, mitigating the harmful effects of pollutants in the exhaust such as carbon monoxide, hydrocarbons, nitrogen oxides, and particulate matter [1].[...]

Platinum Group Metals: A Review of Resources, Production and Usage with a Focus on Catalysts

“…Initially, CO and hydrocarbon oxidation were all that was required under early autoexhaust regulation, but this moved to stricter requirements for lower NO x emissions eventually requiring catalytic conversion of the NO x as opposed to further engine design modification, which could not achieve the emissions requirements [25]. This change led to the three-way catalytic converter in the 1980s [137,138]. Diesel engines provided some of the biggest challenges since they required, in addition to the removal of other emissions, removal of carbon.…”

“…PGM demand for 2020 was lower than recent years and is attributed to the global Covid-19 pandemic [27]. Pt and Pd are used in the auto industry to reduce carbon monoxide (CO) and unburnt hydrocarbons (HC) emissions by oxidation to CO 2 and water [137,139]. Rh is primarily used in NO x reduction and is not usually substituted by Pd or Pt [14,138].…”

“…In larger vehicles, a non-PGM catalyst is used for NO x reduction based on urea and will not be further discussed here. There are ongoing issues with catalyst design, particularly with deactivation during air flow over the catalyst, where Rh dissolution into ceria, zirconia, or sintering may occur [141], as well as efficiency improvements in internal combustion engines which lead to lower catalyst operating temperatures [137].…”