Fe-MOF by ligand selective pyrolysis for Fenton-like process and photocatalysis: Accelerating effect of oxygen vacancy

• H-MIL-53 with oxygen vacancy was prepared by ligand selective pyrolysis. • Synergistic effect of photocatalysis and Fenton. • Oxygen vacancy accelerates •O 2 − by increasing electron hole separation. • Unsaturated coordination iron accelerates H 2 O 2 to produce •OH. The combination of Fenton catalyst and photocatalyst will lead to the decrease in light absorption on the photocatalyst, and it is difficult for Fe 3+ to be converted into Fe 2+ on the Fenton catalyst, resulting in poor Fenton-like process and photocatalysis effect. Preparing catalysts containing oxygen vacancies (OVs) can simultaneously increase the light absorption and the cycle of Fe(Ⅲ) to Fe(Ⅱ) to improve the catalytic efficiency of Fenton-like process and photocatalysis. A mesoporous H-MIL53 with OV was constructed by ligand selective pyrolysis. The formation mechanism of H-MIL-53 vacancy was analyzed by XPS, EPR, FTIR and TG. XPS, EPR, FTIR and TG showed that calcination caused the fracture of Fe-O bond resulted in OV and coordinative unsaturated Fe site. H-MIL-53 showed higher degradation efficiency of tetracycline hydrochloride (93%) and high recycling performance. The electron-rich OV could activate the dissolved oxygen to produce •O 2 − through phot-introduced electrons, while the electron-poor iron site can activate H 2 O 2 to produce •OH. These results provide a new direction for the construction of metal-organic framework (MOF) containing OV for application in Fenton-like process and photocatalysis.