Enhancement of visible‐light photocatalytic degradation performance over nitrogen‐deficient g‐C₃N₄/KNbO₃ heterojunction photocatalyst

Abstract

BACKGROUND The formation of heterojunction is an effective mean for increasing the photocatalytic activity of single‐phase semiconductor photocatalyst. RESULTS In this report, KNbO3/N‐defected g‐C3N4 (KNO/CNx) composites were prepared by an impregnation heat method. The optimized photocatalyst 3% KNO/CNx possesses excellent photocatalytic activity (100 mL, 10 mg/L; 84% degradation within 120 min) in the degradation of tetracycline (TC) under visible light (λ > 420 nm), and it can reach about 125, 10.71 and 3.75 times the degradation kinetic constants, compared with KNO, CN, and CNx, respectively. Furthermore, 3% KNO/CNx possesses relatively high stability during the entire photoreaction process. CONCLUSION This enhanced photocatalytic activity of KNO/CNx is mainly ascribed to the synergistic effect between the heterojunction and defect engineering, which expand the visible‐light adsorption and accelerate the separation efficiency of photo‐induced electron–hole pairs. The research is expected to be used to improve the structure and properties of KNO‐based composites, which provides a possibility for practical application of environmental restoration. © 2020 Society of Chemical Industry

Development of Cuboidal KNbO3@α-Fe2O3 Hybrid Nanostructures for Improved Photocatalytic and Photoelectrocatalytic Applications

“… 58 After irradiation of the heterostructure with white light, the electrons get excited from the valance band of α-Fe 2 O 3 to the conduction band and the holes created in the valance band are transferred to the valance band of KNbO 3 via the interface formed between KNbO 3 and α-Fe 2 O 3 ; therefore preventing the recombination of charge carriers, which in turn results in the enhanced PEC and photocatalytic activity of the heterostructured photocatalyst. 55 − 57 …”

Catalytic Applications of Non‐Centrosymmetric Oxide Nanomaterials

“…[47] From the L-H mechanism involving MB degradation, a fast reaction kinetics of (10.834 � 0.633 × 100) h À 1 was, however, correlated to the surface energy, since high surface energy implies a better adsorption of the organic species. Other reports [48,126,127] demonstrated the applicability of KNbO 3 either as a doped system or heterostructure for H 2 evolution and photocatalytic synthesis of NH 3 via N 2 reduction . For example, the structural phase dependence of KNbO 3 on photocatalytic hydrogen generation was investigated by Zhang et al [126] While the cubic KNbO 3 perovskite has high symmetry implying a zero net spontaneous polarization in terms of crystal symmetry and the spontaneous polarization is forbidden by inversion symmetry, it is surprising that the cubic phase has superior photocatalytic activity compared to the orthorhombic and tetragonal phases, which should crystallize in low symmetry and a distorted NbO 6 .…”

“…In the same vein, a heterostructure of nitrogen‐deficient g‐C 3 N 4 ‐KNbO 3 was prepared for the photocatalytic decomposition of tetracycline [127] . The nitrogen‐deficient graphitic carbon nitride provided a porous stable matrix that was embedded with the oxide perovskite.…”

Efficient photocatalytic degradation of tetracycline by Z-scheme CuSnO3/g-C3N4 heterojunctions coupling with H2O2 under visible light irradiation

“…However, incompletely degraded antibiotics are still highly toxic and resistant drugs, with long-term accumulation having adverse effects on health and ecosystem stability for animals and humans. [1][2][3][4][5] Tetracycline (TC), one of the most common antibiotics in aquatic habitats, has recently been found in water with the abuse of TC. [6][7][8] More importantly, TC cannot be eliminated easily in sunlight, so the accumulation of TC poses a serious threat to human health and aquatic ecosystems.…”