... 15 lanthanide elements with atomic numbers 57 through 71, namely, La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm ... ), and Lu (lutetium)2.Our Rare Earth Metals Catalyst(Al2O3,La,Ce,Y,Zr complex catalyst) can purify the waste gas ...