Interface Engineering of Co(OH)₂ Nanosheets Growing on the KNbO₃ Perovskite Based on Electronic Structure Modulation for Enhanced Peroxymonosulfate Activation

Abstract

Material-enhanced heterogonous peroxymonosulfate (PMS) activation on emerging organic pollutant degradation has attracted intensive attention, and a challenge is the electron transfer efficiency from material to PMS for radical production. Herein, an interface architecture of Co­(OH)2 nanosheets growing on the KNbO3 perovskite [Co­(OH)2/KNbO3] was developed, which showed high catalytic activity in PMS activation. A high reaction rate constant (k 1) of 0.631 min–1 and complete removal of pazufloxacin within 5 min were achieved. X-ray photoelectron spectroscopy, X-ray absorption near edge structure spectra, and density functional theory (DFT) calculations revealed the successful construction of the material interface and modulated electronic structure for Co­(OH)2/KNbO3, resulting in the hole accumulation on Co­(OH)2 and electron accumulation on KNbO3. Bader topological analysis on charge density distribution further indicates that the occupations of Co-3d and O-2p orbitals in Co­(OH)2/KNbO3 are pushed above the Fermi level to form antibonding states (σ*), leading to high chemisorption affinity to PMS. In addition, more reactive Co­(II) with the closer d-band center to the Fermi level results in higher electron transfer efficiency and lower decomposition energy of PMS to SO4 •–. Moreover, the reactive sites of pazufloxacin for SO4 •– attack were precisely identified based on DFT calculation on the Fukui index. The pazufloxacin pathways proceeded as decarboxylation, nitroheterocyclic ring opening reaction, defluorination, and hydroxylation. This work can provide a potential route in developing advanced catalysts based on manipulation of the interface and electronic structure for enhanced Fenton-like reaction such as PMS activation.

Modulating the Electronic Coordination Configuration and d-Band Center in Homo-Diatomic Fe2N6 Catalysts for Enhanced Peroxymonosulfate Activation

“…The d-band center level of Fe in Fe 2 CN is −2.54 eV, which was shifted to the Fermi level relative to −4.45 eV in Fe 1 CN and −6.85 eV in Fe n CN. Therefore, a higher d-band center level may indicated that the better activity for the catalytic reaction was attributed to the coupling with the Fe-3d orbits of adjacent Fe atoms. , …”

“…Therefore, a higher d-band center level may indicated that the better activity for the catalytic reaction was attributed to the coupling with the Fe-3d orbits of adjacent Fe atoms. 16,41 Atomic Structure and Chemical State of Fe x CN. The preparation procedure of Fe 1 CN and Fe 2 CN is illustrated in Figure 2a,b.…”

Exploration of atomic interfaces with inherent oxygen vacancies in zirconia for toluene oxidation

“…5,6 For example, Liu et al constructed an interface architecture by growing Co(OH) 2 nanosheets on the KNbO 3 perovskite and achieved high catalytic activity for peroxymonosulfate activation. 7 Zhang et al discovered that a unique Co 3 O 4 /TiO 2 p–n heterojunction with interface defects could induce the improvement of oxygen mobility and the generation of surficial reactive oxygen, thus accelerating the photothermal catalytic degradation of toluene. 8 Liu et al reported a high-efficiency monolithic catalyst with interfaces by in situ growth of MOFs, and it was found that the interfacial interaction could accelerate the fracture of the Co–O bond, which is beneficial to molecular oxygen activation and acetone oxidation.…”

Sulfur vacancies on MoS2 enhanced the activation of peroxymonosulfate through the co-existence of radical and non-radical pathways to degrade organic pollutants in wastewater

“…Accordingly, it has to introduce external activation factors including heat, 6 alkaline conditions, 7 and homogeneous 8,9 and heterogeneous catalysts. [3][4][5][10][11][12][13][14][15] Among them, a heterogeneous catalyst for the activation of PMS is a good strategy for repeated use, realization of radical and non-radical routes, etc. The activation of PMS by heterogeneous catalysts containing defect sites has attracted much attention in the past few years.…”