Mechanochemical synthesis of microscale zero-valent iron/N-doped graphene-like biochar composite for degradation of tetracycline via molecular O2 activation

•A novel microscale zero-valent iron/N-doped graphene-like biochar composite (mZVI/NGB) was successfully synthesized via a mechanochemical method.•mZVI/NGB exhibited significantly enhanced H2O2 generation.•mZVI/NGB forms a self-sustaining catalytic system, with mZVI serve as electron pool and NGB as catalyst for H2O2 generation.•mZVI/NGB exhibited excellent reusability and can be magnetically collected.