MoO_3 can dissolve in SnO_2 forming solid solution in the catalyst prepared by precipitation method, while Mo ions diffuse into the bulk of SnO_2 in the catalyst prepared by impregnation.

• 沉淀法所得样品中MoO_3可溶于SnO_2形成固溶体; 浸渍法则可发生钼离子向SnO_2体相的扩散;