Biomass-derived sustainable hypergolic rocket propellants with hydrogen peroxide

Abstract

Sustainable fuels, derived from various renewable biological sources, are having a significant impact on land and marine transportation, as well as on aviation. However, in the case of the space sector, this advancement is limited. In an effort to prepare a sustainable rocket fuel (SRF) from readily available bioresources, herein we report for the first time the valorization of a widely available biomass – coconut husk into hypergolic composite fuel. We showed that the hypergolic reactions of various formulations of coconut husk-derived SRFs with a green oxidizer – H₂O₂ (95%) could be promoted with the addition of catalytic amounts of guanine-containing polymeric complexes of manganese or copper (Mn–GU or Cu–GU). It was found that the top-performing fuel formulation, with a total manganese content of just 2 wt%, showed an impressive ignition delay time below 50 ms. Mechanistic studies exploring the structure–ignition capability relationships of coconut husk-derived SRFs and Mn–GU and Cu–GU materials revealed that the nitrate content of coconut husk-derived SRFs and the metal–ligand cooperation in the Mn–GU and Cu–GU complexes played important roles in the ignition process of our novel SRF formulations.