Base metal catalyst and method of using same

A method of treating a gas stream generated by a motorcycle, the method comprising:

• contacting a gas stream containing hydrocarbons, carbon monoxide and nitrogen oxides and generated by a motorcycle under both rich and lean engine operating conditions with a base metal catalyst composition comprising
• a support including at least 10% by weight of reducible ceria doped with up to about 60% by weight of one or more of oxides selected from the group Al, Pr, Sm, Zr, Y, Si, Ti and La;
• and
• a base metal oxide on the reducible ceria support, the base metal selected from one or more of Ni, Fe, Mn, Cu, Co, Ba, Mg, Ga, Ca, Sr, V, W, Bi and Mo, the base metal catalyst composition effective to promote a steam reforming reaction of hydrocarbons and a water gas shift reaction to provide H2 as a reductant to abate NOx,
• thereby removing at least a part of the hydrocarbons, carbon monoxide and nitrogen oxides in gas stream.