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用XPS考察了USY和FSY超稳Y型沸石及其起始原料NH_4Y沸石的表面组成,并结合Ar~+刻蚀技术与其体相组成进行了比较。结果表明,NH_4Y沸石的铝分布基本均匀一致,经超稳化处理后,沸石表面组成发生了很大的变化。用(NH_4)_2SiF_6液相脱铝补硅法制备的FSY表面呈缺铝特征,其表面铝原子浓度比体相低8～10％;而用传统水热法制备的USY具有典型的富铝表面,其表面铝原子浓度比体相高30％左右。USY表面富铝主要是由于USY“次表面”(Subsurface)附近的非骨架铝类迁移到表面所致。内层的非骨架铝类在常规水热超稳处理条件下一般则很难迁移,仍然留有在USY晶体内部。
The surface compositions of the USY and FSY ultrastable Y zeolites and their starting materials, NH 4 Y zeolites, were investigated by XPS and their phase composition was compared with Ar + + etching techniques. The results show that the distribution of aluminum in NH_4Y zeolite is basically the same, and the composition of the surface of the zeolite changes greatly after the ultrastable treatment. The FSY surface prepared by (NH_4) _2SiF_6 liquid-phase de-alumination silica-forming method is aluminum-deficient, and the surface aluminum atom concentration is 8-10% lower than that of the bulk phase. USY prepared by the traditional hydrothermal method has a typical aluminum-rich surface , The surface of the aluminum atom concentration of about 30% higher than the body phase. The aluminum-rich surface of the USY is mainly due to the migration of non-frameworkal aluminum species near the USY “Subsurface” to the surface. The inner non-framework aluminum is generally difficult to migrate under conventional hydrothermal ultra-stable conditions and remains inside the USY crystal.