In-situ and self-distributed: A new understanding on catalyzed thermal decomposition process of ammonium perchlorate over Nd2O3

Catalyzed thermal decomposition process of ammonium perchlorate (AP) over neodymium oxide (Nd2O3) was investigated. Catalytic performances of nanometer-sized Nd2O3 and micrometer-sized Nd2O3 were evaluated by differential scanning calorimetry (DSC). In contrast to universal concepts, catalysts in different sizes have nearly similar catalytic activities. Based on structural and morphological variation of the catalysts during the reaction, combined with mass spectrum analyses and studies of unmixed style, a new understanding of this catalytic process was proposed. We believed that the newly formed chloride neodymium oxide (NdOCl) was the real catalytic species in the overall thermal decomposition of AP over Nd2O3. Meanwhile, it was the "self-distributed" procedure which occurred within the reaction that also worked for the improvement of overall catalytic activities. This work is of great value in understanding the roles of micrometer-sized catalysts used in heterogeneous reactions, especially the solid–solid reactions which could generate a large quantity of gaseous species. - Graphical abstract: In-situ and self-distributed reaction process in thermal decomposition of AP catalyzed by Nd2O3. - Highlights: • Micro- and nano-Nd2O3 for catalytic thermal decomposition of AP. • No essential differences on their catalytic performances. • Structural and morphological variation of catalysts digs out catalytic mechanism. • This catalytic process is "in-situ and self-distributed" one