Nanohybrids of reduced graphene oxide and cobalt hydroxide (Co(OH)2|rGO) for the thermal decomposition of ammonium perchlorate.

The catalytic activity of nanoparticles of cobalt hydroxide supported on reduced graphene oxide, Co(OH)2|rGO, was studied for the decomposition of ammonium perchlorate (AP), the principal ingredient of composite solid propellants. Co(OH)2|rGO was synthesized by an in situ reduction method, which avoided the application of extremely high temperatures and harsh processes. rGO stabilized the nanoparticles effectively and prevented their agglomeration. The performance of Co(OH)2|rGO as a catalyst was measured by differential scanning calorimetry. Co(OH)2|rGO affected the high-temperature decomposition (HTD) of AP positively, decreasing the decomposition temperature of AP to 292 °C, and increasing the energy release to 290 J g-1. The diminution of the HTD of AP by Co(OH)2|rGO is in between the best values reported to date, suggesting its potential application as a catalyst for AP decomposition.

Novel in situ synthesis of copper nanoparticles supported on reduced graphene oxide and its application as a new catalyst for the decomposition of composite solid propellants.

The catalytic activity of graphene oxide (GO), reduced graphene oxide (rGO), copper nanoparticles (CuNP) and rGO supported copper nanoparticles (rGO|CuNP) was investigated for the thermal decomposition of ammonium perchlorate (AP). GO was synthesized using a methodology based on hydrophilic oxidation, while an environmentally friendly and non-toxic reducing agent, l-ascorbic acid, was applied for the in situ reduction of copper and GO. The supporting rGO reduced the mean size of the copper nanoparticles from approximately 6 to 2 Å due to the presence of stabilizing functional groups on the graphitic structure. Theoretical studies through Density Functional Theory revealed the important role of the epoxy and carbonyl groups of rGO on the stabilization of copper. The thermal decomposition process was studied based on DSC and TGA. GO, and rGO did not show a significant catalytic influence in the decomposition of AP. CuNP reduced the decomposition temperature of AP in greater magnitude than rGO|CuNP however, the synergistic effect of the rGO and CuNP increased the energy release significantly.

Graphene Oxide Quantum Dots as the Support for the Synthesis of Gold Nanoparticles and Their Applications as New Catalysts for the Decomposition of Composite Solid Propellants.

Graphene oxide quantum dot (GOQD) and reduced GOOD (rGOQD) were synthetized using a simple and straight methodology based on an oxidative treatment and sonication. GOQD and rGOQD were used as supporting agents for the in situ generation of gold nanoparticles, avoiding the use of additional stabilizers. GOQD resulted as a better support than rGOQD because of the presence of higher functional groups that can interact with gold. Theoretical studies through density functional theory revealed the important role of the epoxy groups of GOQD on the stabilization of gold. GOQD and GOQD-Au were tested for the first time as catalysts for the decomposition of solid composite propellants. GOQD not only lowered the decomposition temperature of ammonium perchlorate (AP) but also enhanced the exothermic heat of AP, in comparison to graphene and GO. GOQD-Au increased the energy release; however, the effect on the decrease of the decomposition temperature of AP was not as significant as other previous reported catalysts.