Catalytic ignition of N(CN)2− ionic liquid-H2O2 with zero-dimensional Cu-MOFs†
Abstract
Ionic liquid-H2O2 is one of the most important proposed systems for green propellants. However, due to its weak oxidizing ability, H2O2 can hardly ignite ionic liquids. Therefore, in this work, four potential low-dimensional metal–organic frameworks (Cu-MOFs 1–4) were first synthesized for the ignition of a N(CN)2− ionic liquid-H2O2 system. The results show that zero-dimensional Cu-MOFs 3–4 could catalyze N(CN)2− ionic liquid-H2O2 from non-ignition to combustion, with an ignition delay time of 30 ms by using Cu-MOF 3–4. Through DMPO-probed EPR tests and DFT calculations, the catalytic mechanism was proposed and it was suggested that H2O2 releases the strong oxidizing ·OH and ·OOH and then electrons are transferred to the ionic liquid by a free radical chain reaction. This work paves the way for the development and applications of ionic liquid-H2O2 as a hypergolic bipropellant.