Heterogeneous activation of H2O2 by defect-engineered TiO2− single crystals for refractory pollutants degradation: A Fenton-like mechanism

Abstract

The heterogeneous catalyst plays a key role in Fenton-like reaction for advanced oxidation of refractory pollutants in water treatment. Titanium dioxide (TiO2) is a typical semiconductor with high industrial importance due to its earth abundance, low cost and no toxicity. In this work, it is found that TiO2 can heterogeneously activate hydrogen peroxide (H2O2, E°=1.78 eV), a common chemical oxidant, to efficiently generate highly-powerful hydroxyl radical, OH (E(0)=2.80 eV), for advanced water treatment, when its crystal shape, exposed facet and oxygen-stoichiometry are finely tuned. The defect-engineered TiO2 single crystals exposed by high-energy {001} facets exhibited an excellent Fenton-like activity and stability for degrading typical refractory organic pollutants such as methyl orange and p-nitrophenol. Its defect-centered Fenton-like superiority is mainly attributed to the crystal oxygen-vacancy, single-crystalline structure and exposed polar {001} facet. Our findings could provide new chance to utilize TiO2 for Fenton-like technology, and develop novel heterogeneous catalyst for advanced water treatment.

Oxygen Vacancy‐Mediated Photocatalysis of BiOCl: Reactivity, Selectivity, and Perspectives

“…As compared with Ti 3d states,t he more dispersed Bi 6p and Bi 6s states can facilitate excited electrons of BiOCl to travel al onger distance. [36] BiOCl has at etragonal matlockite (PbFCl-type) structure (space group P4/nmm)c ontaining six atoms in ap rimitive cell with the lattice parameters being a = b = 0.3891 nm, c = 0.7369 nm, a = b = g = 908 8.B enefiting from its geometric structure,B iOCl easily crystallizes into singlecrystalline two dimensional (2D) nanosheets anisotropically via hydrothermal or solvothermal method. Then anosheets are of layered structure,ascharacterized by the [Cl-Bi-O-Cl] slabs being stacked together by the van der Waals interaction via the [Cl···Cl] atoms,o ffering high fraction of exposed surface for the facet effect investigation (Figure 1c).…”

Effects of Particle Size on the Structure and Photocatalytic Performance by Alkali-Treated TiO2

“…ESR can also be used to confirm the presence of oxygen vacancies. As shown in Figure 6d, there 263 is a sharp signal at g = 2.004, which is identified as the electrons trapped on surface oxygen To further confirm the radicals generated in the reaction process of TiO 2 -24, ESR analysis was also performed using DMPO as the radical spin-trapping probe [50,51]. After illuminating with visible light for 10 min, TiO 2 -24 exhibits the strongest intensity of DMPO-O 2…”

“…To further confirm the radicals generated in the reaction process of TiO2-24, ESR analysis was 258 also performed using DMPO as the radical spin-trapping probe [50,51]. After illuminating with 259 visible light for 10 min, TiO2-24 exhibits the strongest intensity of DMPO-O2 •− signals, indicating that 260 the amounts of O2 •− produced in TiO2-24 is much larger than that for pristine TiO2 and TiO2-48,…”

Structurally modified CuFe2O4/persulfate process for acetaminophen scavenging: high efficiency with low catalyst addition

“…After modification, a defect‐engineered analog [e.g. Oxygen (O)‐deficiency] can improve the electronic, adsorption and catalytic properties . Therefore, O‐deficient CuFe 2 O 4 was obtained using CuFe 2 O 4 as the precursor via hydrogen reduction to overcome the disadvantage of CuFe 2 O 4 in activating PS.…”