Combining two active states of FeOx in-situ in molecular sieve to deliver enhanced catalytic activity via creating special configuration and synergy

Abstract

Combining different active states of metal species together in special configuration might trigger interesting synergetic effect for catalytic process. As a proof-of-concept, the present study has developed an ingenious approach to reach functional mesoporous molecular sieve which in-situ encapsulates two different states of highly-active FeOx inside centered core and nano-tunnel of mesoporous silica, respectively. The α-Fe₂O₃ <i>in-situ</i> immobilized nanoneedles coated by the porous silica afford ∼5 nm diameter, plus highly-dispersed Fe₂O₃ cluster-like species attachment in confined mesopore, which synergistically contributes to high activity and stabilization of catalyst. The combined iron oxides in special configuration deliver an appreciable catalytic activity in phenol hydroxylation (46.4% conversion, 87.9% benzenediol selectivity) during multiple catalytic cycles, compared to some reported results, which benefited from accelerating production of oxidative free radicals from H₂O₂ and the tailored micrpopore (∼1.4 nm) which could enhance the catalytic selectivity of targeted products. Furthermore, the photocatalytic antimicrobial effect of Fe catalyst against <i>Escherichia coli</i> was also demonstrated via the constructed synergy of two FeOx nanospecies with assistance of light.