氮化磷酸铝的酸碱性研究

STUDY ON THE ACID BASE PROPERTIES OF ALUMINOPHOSPHATE OXYNITRIDES

利用ＮＨ３ －ＴＰＤ， ＣＨ３ＣＮ－ＴＰＤ 和正丙胺分解探针反应研究了不同氮含量的氮化磷酸铝的表面酸碱性。ＮＨ３－ＴＰＤ结果表明， 高温通氨氮化使磷酸铝的酸量逐渐减少。ＣＨ３ＣＮ－ＴＰＤ研究表明， 氮化过程生成了两种不同碱强度的碱中心， 随着样品氮含量的增加， 碱性位增加， 碱性增强。但是氮化磷酸铝的碱性较氧化镁弱。正丙胺在较高氮含量的氮化磷酸铝上有较高的脱氢选择性也表明这些样品有较多和较强的碱性中心。

By means of NH 3 TPD,CH 3CN TPD and n propylamine decomposition probe reaction,the acid base properties of aluminophosphate oxynitrides (AlPON) with variable nitrogen contents have been investigated.NH 3 TPD study shows that the nitridation decreases the total number of acid sites,but not their strength.CH 3CN TPD shows that two kinds of base sites are formed during the nitridation process.With the increase of nitrogen content,not only the number but also the strength of base sites increase.However,the AlPONs have weaker base sites than that of MgO.The higher selectivities of n propylamine dehydrogenation over the samples with higher nitrogen contents also suggest that these materials have more and stronger basic sites.