Azadirachta indica plant-assisted green synthesis of Mn₃O₄ nanoparticles: Excellent thermal catalytic performance and chemical sensing behavior

The leaf extract of Azadirachta indica (Neem) plant was utilized as reducing agent for the green synthesis of Mn₃O₄ nanoparticles (NPs). The crystalline analysis demonstrated the typical tetragonal hausmannite crystal structure of Mn₃O₄, which confirmed the formation of Mn₃O₄ NPs without the existence of other oxides. Green synthesized Mn₃O₄ NPs were applied for the catalytic thermal decomposition of ammonium perchlorate (AP) and as working electrode for fabricating the chemical sensor. The excellent catalytic effect for the thermal decomposition of AP was observed by decreasing the decomposition temperature by 175 °C with single decomposing step. The fabricated chemical sensor based on green synthesized Mn₃O₄ NPs displayed high, reliable and reproducible sensitivity of ∼569.2 μA mM^-1 cm^-2 with reasonable limit of detection (LOD) of ∼22.1 μM and the response time of ∼10 s toward the detection of 2-butanone chemical. A relatively good linearity in the ranging from ∼20 to 160 μM was detected for Mn₃O₄ NPs electrode based 2-butanone chemical sensor.