Exhaust gas purification catalyst and method for producing it

The present invention relates to an exhaust gas purification catalyst that can homogeneously inhibit growth of a plurality of the fine particles at high temperature, and prevent lowering in catalytic activity, as well as a method for producing it. The exhaust gas purification catalyst of the present invention has fine composite metal particles containing a platinum-group metal and tungsten. Moreover, in the exhaust gas purification catalyst of the present invention, when the fine composite metal particles in the exhaust gas purification catalyst have been analyzed by STEM-EDX, the tungsten content of at least 80% of the fine composite metal particles based on number, is in the range of 10% to 350% of the mean content of tungsten in a plurality of the fine composite metal particles. 本发明涉及废气净化催化剂及其制造方法。本发明涉及种能够在高温下均匀地抑制多个微粒的粒生长、防止催化剂活性降低的废气净化催化剂及其制造方法。本发明的废气净化催化剂具有包含铂族金属和钨的复合金属微粒。另外，在本发明的废气净化催化剂中，在利用STEM－EDX对废气净化催化剂中的复合金属微粒进行分析时，以个数基准计80％以上的复合金属微粒的钨的含量在多个复合金属微粒中的钨的平均含量的10％～350％的范围内。