Development of TiO 2 decorated Fe 2 O 3 QDs/g-C 3 N 4 Ternary Z-scheme photocatalyst involving the investigation of phase analysis via strain mapping and its photocatalytic performance under visible light illumination

This study reported the fabrication of TiO 2 -decorated Fe 2 O 3 QDs/g-C 3 N 4 ternary Z-scheme photocatalyst via low-temperature calcination followed by a nonaqueous route with tunable particle size and strong interfacial contact. The subsequent Fe 2 O 3 QDs/g-C 3 N 4 and TiO 2 /Fe 2 O 3 QDs/g-C 3 N 4 were investigated in terms of structure, morphology, optical properties, and surface chemical composition analysis via transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive x-ray spectroscopy (EDX), UV–visible spectroscopy, ESR and photoluminescence spectroscopy (PL). The crystalline parameters of the samples were investigated by X-ray diffraction (XRD) The Williamson-Hall method and geometrical phase analysis of HRTEM micrographs were employed to investigate lattice defects. Under visible light, the photocatalytic capabilities of as-fabricated TiO 2 /Fe 2 O 3 QDs/g-C 3 N 4 were examined by degrading Rhodamine B (RhB), and an enhancement in photocatalytic efficacy was found. TiO 2 works as a primary photosensitizer, providing extra photoinduced electrons influenced by oxygen vacancies, while Fe 2 O 3 acts as a "bridge" for electron transport from the TiO 2 moiety to the g-C 3 N 4 thereby establishing an indirect charge transport pathway based on the Z-scheme. Radical scavenging tests were conducted to further explore the cause of increased activity and degradation mechanisms. Designing materials with oxygen vacancies and optimized structures can lead to improved solar energy conversion capabilities, particularly regarding contaminant removal. The proposed technique might be a viable option for the removal of rhodamine b compounds and for remedying freshwater reservoirs. Graphical Abstract TiO 2 /Fe 2 O 3 QDs/g-C 3 N 4 Ternary Z-Scheme Photocatalysts! A facile strategy is exploited to modulate the crystallinity and surface properties of TiO 2 . TiO 2 is incorporated into Fe 2 O 3 QDs/g-C 3 N 4 through solvothermal treatment, which results in the formation of surface flaws and lattice-oxygen activated regions as well as the transformation of the Fe 2 O 3 QDs/g-C 3 N 4 heterojunction into an indirect z-scheme system by rational modulation of the band alignment of two systems. The electron–hole pair is efficiently separated, conserving the electron reduction capability and the electron oxidation capability of the hole. The adapted structure and mesocrystalline nature resulted in a 7.3-fold improvement in the photocatalytic performance of TFCN over pure g-C 3 N 4 .