Surface Interface-Driven Catalytic Decomposition of Nitroguanidine by Size-Tuned PbCO₃ Suppressed Toxic Emissions and Enhanced Thermal Reactivity

Nitroguanidine (NQ) is a high-nitrogen energetic compound whose high decomposition temperature and incomplete combustion hinder its efficiency and environmental performance. Herein, we report a nanoscale interfacial-catalysis strategy in which lead carbonate (PbCO3) is transformed via high-energy ball milling into nanostructured particles, then ultrasonically dispersed to form intimate contact interfaces with NQ crystals. Detailed structural characterization (XRD, SEM) confirmed the formation of PbCO3 with sub-100 nm dimensions and a high surface area, promoting extensive NQ–catalyst interfacial interactions. TGA–DSC revealed that these engineered interfaces lower the onset decomposition temperature of NQ by up to 23.7 °C and reduce its apparent activation energy from 130.9 to 105.2 kJ·mol–1, indicative of accelerated surface-mediated bond rupture. TGA-FTIR analyses demonstrated that PbCO3 surfaces facilitate early stage heat release and redirect reaction pathways to suppress HCN formation, converting it into cleaner exhaust species. Solid-phase residue examination (XPS, XRD) further demonstrated that the reduction of solid-phase residues in the reaction system improves overall combustion integrity. By elucidating how the interface chemistry of nanostructured PbCO3 regulates the kinetics and product distribution of NQ combustion, a new avenue has been opened for the design of advanced energy materials with customized properties.