Enhancing photocatalytic hydrogen peroxide production of Ti-based metal–organic frameworks: The leading role of facet engineering

Rational construction of the facet engineering over metal-organic frameworks is of significant interest for enhancing photocatalytic performance, yet the role of modulator except regulating facet is largely ignored. Herein, facet engineering of NH₂-MIL125 (aMIL) was achieved through the facile one-pot method by controlling the concentration of acetic acid modulator. The probable domino effects induced with the detectable modulator were extensively investigated, evidencing the multi-position in one mode contained powder X-Ray diffraction (PXRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS), etc. Meanwhile, correlation among the {111} facets engineering, the degree of structural defects, and the performance of photocatalytic hydrogen peroxide (H₂O₂) production was studied in detail, revealing that facet and defect engineering respectively play positive and relatively negative roles in the photocatalytic oxygen reduction reaction (ORR) with a volcano-type trend. aMIL-3 photocatalyst could deliver H₂O₂ production rate of 925.8 µmol·h⁻¹·g⁻¹ (2.03-fold of aMIL) under visible-light irradiation and a quantum yield of 1.08% at 420 nm. [Figure not available: see fulltext.]