Heterogeneous Fe(IV) O mediated fenton-like process on Fe-Zr heterojunction for selective oxidation of organic pollutants at near neutral pH

• Fe-Zr (1 1 0)-(1 0 0) heterojunction were prepared by the gradient crystallization. • Iron sites at (1 1 0)-(1 0 0) interface showed the highest H 2 O 2 activation ability. • Heterogeneous Fe(IV)=O was formed at the (1 1 0)-(1 0 0) interface. • Heterogeneous Fe(IV)=O exhibits good selective oxidation performance. Remarkable heterogeneous Fe(IV)=O (≡Fe(IV)=O) mediated Fenton-like process on (1 1 0)-(1 0 0) heterojunction of Fe-Zr bimetallic oxide was proposed in this work for selective oxidation of organic pollutants under near-neutral conditions. The formation of heterojunction shortened the Fe-O bond length by 0.14 Å and increased the binding energy of Fe 2p 3/2 orbital by 0.8 eV on Fe-Zr (1 1 0)-(1 0 0) interface, compared with that on Fe 2 O 3 (1 1 0) facet. This will promote the cyclic complexes of Fe(II)-[OOH] + formation on Fe-Zr (1 1 0)-(1 0 0) interface. Besides, energy barrier of Fe(II)-[OOH] + on (1 1 0)-(1 0 0) heterojunction was 10.6 kJ mol -1 lower than that on Fe 2 O 3 (1 1 0) facet. It will facilitate the inner two-electron transfer process to generate ≡Fe(IV)=O. And electrostatic repulsion and electrophilic addition enable ≡Fe(IV)=O to selectively oxidize target organic pollutants in the system containing ions and humic acids. This work provides a fundamental information toward the structure-performance relationship between heterojunction structure and ≡Fe(IV)=O formation, and it will enlighten the selective oxidation of pollutants in wastewater treatment.