Dual roles of amphiphilic triblock copolymer P123 in synthesis of α-Fe nanoparticle/ordered mesoporous silica composites

► Well dispersed α-Fe nanoparticles in ordered mesoporous silica has been synthesized. ► Evaporation induced self-assembly is strategically combined with carbothermal reduction. ► Fe species can be in situ reduced to α-Fe nanoparticles via carbothermal reduction. ► Amphiphilic triblock copolymer P123 plays dual roles in self-assembly and carbothermal reduction.