ZIF-8 derived ZnO: a facile catalyst for ammonium perchlorate thermal decomposition

Abstract

The growing interest in sustainable technology advancements necessitates the development of green and environmentally benign facile catalysts for rocket propellants, which eliminates the use of toxic and/or hazardous reagents and encourages the efficient use of base metals. Here, ZIF-8 was employed as a sacrificial template for the synthesis of porous, low-cost, simple and eco-friendly ZnO via simple calcination for the thermal decomposition studies of ammonium perchlorate (AP). Structural analyses reveal that the complete conversion of ZIF-8 to ZnO occurs only at high temperatures. Prolonged calcination results in the lowering of the band gap, the availability of more polar planes and the presence of oxygen defects on the ZnO surface, which facilitate the faster decomposition of perchloric acid and ammonia intermediates of AP decomposition. In the presence of 1 wt% ZnO calcined at 500 °C (Z500), the two-stage decomposition pattern shows an amalgamation tendency with a significant reduction in decomposition temperature (90 °C), followed by a significant drop in the activation energy from 149 kJ mol⁻¹ to 130 kJ mol⁻¹ in the presence of Z500. Later, TG-MS analysis shows the catalyzed AP decomposition via the evolution patterns of decomposition products NO, NO₂, N₂O, Cl, HCl, NH₂, O₂ and Cl₂. Hence, ZIF-8-derived ZnO is a facile catalyst as it effectively catalyzes the AP thermal decomposition with a minimal catalytic content and eco-friendly synthesis procedure.