Automobile exhaust emission control by catalysts

The past year has seen a wealth of published articles from around the world related to automobile exhaust emission control. The applied automotive catalysis work continues in response to the need for robust systems that comply with new, stricter regulations for the control of nitric oxides (NO(x)), hydrocarbons and carbon monoxide under an expanded range of driving conditions that includes higher speeds and air conditioner operation. The search also continues for catalysts that effectively reduce nitric oxide levels in lean feed streams. Although promising results continually emerge, no catalysts have surfaced that meet all the desired requirements for lean burn gasoline or diesel engines. In the absence of effective lean NO(x) catalysts, NO(x) sorption systems are emerging as the alternative method for lean NO(x) control in gasoline engines.