SnS₂/Bi₄Ti₃O₁₂ Heterostructure Material: A UV‐Visible Light Active Direct Z‐Scheme Photocatalyst for Aqueous Phase Degradation of Diazinon

Abstract

In this study, a series of Z-scheme SnS 2 /Bi 4 Ti 3 O 12 heterostructure photocatalyst materials were synthesized by a two-step process. Initially, Bi 4 Ti 3 O 12 (BT) nanopellets with planar dimension of 350-400 nm were prepared by a facile combustion synthesis route. The SnS 2 nanoparticles (10-20 nm) were subsequently decorated over BT surface using a hydrothermal method. The heterostrucure materials possess orthorhombic BT and hexagonal SnS 2 crystalline phases with high interfacial contact and strong interaction at microscopic level. Optical and photoelectrochemical (PEC) measurements suggest improved UVvisible light absorption and enhanced charge carrier separation and migration properties. The SnS 2 /Bi 4 Ti 3 O 12 materials displayed excellent photocatalytic activity for degradation of diazinon insecticide (> 90 % with k app ∼ 0.019 min À 1 ) in aqueous media under UV-visible light illumination. The valence band (VB) holes and * OH radicals were identified as major transient species responsible for photodegradation of diazinon. A Z-scheme electron transfer process has been proposed to explain adequately the generation of these radicals which was deduced from PEC measurements, scavenger and radical trapping experiments. Mechanistic study revealed that diazinon degradation occured in a series of steps to produce 2-isopropyl-6methyl-pyrimidin-4-ol as a major intermediate which was further mineralized over the photocatalyst surface. The process potential of the developed photocatalytic method has been tested for different water matrices and interfering anionic species with radical quenching activity.

Recent advances of semiconductor photocatalysis for water pollutant treatment: mechanisms, materials and applications

“…This was attributed to the rapid generation of the ˙OH and O 2 ˙ − under light irradiation, involving a Type-I bridged coupled Z-scheme charge transfer mechanism. Das et al 118 reported a Z-scheme SnS 2 /Bi 4 Ti 3 O 12 heterojunction photocatalyst material that exhibited good photocatalytic degradation activity for diazinon (DZN) under UV-visible light. This was attributed to the orthorhombic Bi 4 Ti 3 O 12 and hexagonal SnS 2 crystalline phases inside the material with a high interfacial contact and a strong interaction at the microscopic level, which improved the photoresponse range and enhanced the carrier separation.…”

Hierarchical UiO-66(−NH2)/CuInS2 S-Scheme Photocatalyst with Controlled Topology for Enhanced Photocatalytic N2 Fixation and H2O2 Production

“…The metal sulfides such as Cu 2 S, Bi 2 S 3 , CdS, SnS 2 , and MoS 2 etc. have recently been studied as emerging photocatalysts because of their small band gap and higher negative conduction band potential. − Due to improved electrical conductivity and redox characteristics, ternary metal sulfides have recently captured more attention from researchers over the binary metal sulfides . By altering their composition and stoichiometry, the band structure of ternary sulfides can be controlled, resulting in a broad range of light sensitivity and programmable redox potential .…”

Highly transparent Bi4Ti3O12 thin-film electrodes for ferroelectric-enhanced photoelectrochemical processes

“…Effective separation of the photogenerated carriers is therefore achieved in the local unit cell. 8 On this basis, several BiTO-based powder systems have been successfully reported over the years, for multiple photocatalytic purposes, [9][10][11][12][13][14][15][16][17][18][19] and recently BiTO has been employed as a catalyst also in the CO 2 photo-reduction reaction, producing CO, [20][21][22][23][24] methanol (CH 3 OH), 21 and methane (CH 4 ). 24 In addition to these already promising photo-catalytic performances, the distortion of the TiO 6 octahedra in the pseudo-perovskite blocks is responsible for the BiTO well-Please do not adjust margins Please do not adjust margins known ferroelectric behavior, 25 which has been proven to represent a strong driving force for bulk charge separation.…”