The present disclosure relates to a composite propellant and a process for its preparation. The composite propellant comprises an oxidizer having a particle size of 2 to 60 �m, and an activated metal boride having a particle size of 0.2 to 10 �m. The activated metal boride has potential to be utilized as catalytic and energetic fuel additive. The process of the present disclosure is simple, cost effective, and scalable.