Ternary Metal Chalcogenide Heterostructure (AgInS₂–TiO₂) Nanocomposites for Visible Light Photocatalytic Applications

Abstract

Hybrid nanoarchitectures of AgInS2 and TiO2 photocatalysts were prepared by using a modified sol–gel method. The experimental results reveal that these nanocomposites display enhanced visible light absorption and effective charge carrier separation compared to their pristine parent samples (AgInS2 or TiO2). 0.5 wt % AgInS2 loading was found to be the optimum concentration for photocatalytic applications. More than 95% of doxycycline degradation was achieved within 180 min of solar light illumination. Similarly, the dopant concentrations at lower values (<2 wt %) exhibited 300 times higher H2 generation rate under visible light irradiation compared to AgInS2 and TiO2. The microbial strains (Escherichia coli and Staphylococcus aureus) exhibited a 99.999% reduction within half an hour of simulated solar light illumination. The computational investigation was employed to understand the structural, electronic, and the dielectric properties of AgInS2 and TiO2 composites. The improved photocatalytic results are explained as a result of the decreased rate of exciton recombination. The current investigation opens up new insights into the use of novel ternary heterostructure nanocomposites for improved visible light activity.

Photocatalytic Hydrogen Evolution Using Ternary‐Metal‐Sulfide/TiO2 Heterojunction Photocatalysts

“…Based on the calculated values (Figure 5A-g), it's proposed that the photogenerated electron-hole pairs, as well as superoxide radicals, are the predominant reactive species participating in the photocatalytic reactions. [39] Afterwards, Ganguly et al systematically investigated the AgBiS 2 /TiO 2 photocatalyst for hydrogen evolution using the similar theoretical and experimental methods [40] and reached conclusions similar to those obtained regarding AgInS 2 /TiO 2 (Figure 5B). [39,40] Based on the above consideration, we can conclude that the photocatalytic hydro-gen evolution rate of TMS/TiO 2 photocatalysts can be optimized by tuning the elements in the TMS, resulting in an optimized crystal and band structure of TMS.…”

“…AgInS 2 is an AgÀ InÀ S TMS with I-III-VI 2 formula which can be crystallized into two different polymorphs: room-temperaturestable tetragonal chalcopyrite structure and high-temperature orthorhombic wurtzite structure. [39,66] Nanocrystals of these phases can be synthesized by different liquid-phase reactions, and the phase transition temperature point is 620 °C. [67,68] Orthorhombic AgInS 2 has a small band gap and excellent photon absorption in the visible region of the electromagnetic spectrum, making it suitable for photocatalytic applications.…”

“…[69] Ganguly et al prepared pristine anatase TiO 2 by sol-gel method from a titanium isopropoxide (TTIP) precursor solution, and carried out computational analysis of the crystal and electronic structure. [39] After optimization, the Ti cations and O anions were octahedrally coordinated, in which the alternate edge and corner sharing were connected to each other (Figure 5A). The band structure calculation of AgInS 2 , using generalized gradient approximation (GGA) Perdew-Burke-Ernzerhof (PBE) functional, is presented in Figure 5A-c and reveal a direct band gap of approximately 0.5 eV.…”

“…[32][33][34][35] Guided by the scientific route of BMS/TiO 2 , the combination of TMS and TiO 2 , constructing AgGaS 2 /TiO 2 , AgIn 5 S 8 /TiO 2 , AgInS 2 /TiO 2 , AgBiS 2 /TiO 2 , CuInS 2 / TiO 2 , and ZnIn 2 S 4 /TiO 2 heterojunction photocatalysts, have been developed for the application of photocatalytic hydrogen evolution via water splitting. [36][37][38][39][40][41][42][43][44][45] However, the systematical summary of TMS/TiO 2 heterojunction photocatalysts is rarely well-introduced expect Yang et al reviewed the ZnIn 2 S 4 -based photocatalysts for hydrogen evolution. [46] This review not only referred to the ZnIn 2 S 4 /TiO 2 based photocatalysts but provided several effective path for further photoactivity enhancement of ZnIn 2 S 4 /TiO 2 based photocatalysts, like doping, vacancy control, and morphology control, which has guiding significance to improve the photocatalytic hydrogen evolution of TMS/TiO 2 photocatalysts.…”

Cathode–Anode Spatial Division Photoelectrochemical Platform Based on a One-Step DNA Walker for Monitoring of miRNA-21

“…Among various miRNA analytical methods, the photoelectrochemical (PEC) technique has attracted extensive attention due to its versatility, high sensitivity, simple equipment, and so forth. − Benefiting from facile preparation, easy modification, high photochemical activity, and stability, the previous works have mainly focused on photoanodic biosensors with n-type semiconductor-sensitized materials such as TiO 2 , BiVO 4 , CdS quantum dots (QDs), and so on. − The n-type semiconductor took electrons as the main carriers and inclined to interact with electron donors to produce a significant photocurrent response. , As a typical ternary n-type semiconductor material, AgInS 2 exhibited fast charge conduction rate under red-light excitation. , Nevertheless, the photoanodic biosensors suffered from insufficient anti-interference performance. The coexisting reducing components in actual samples (such as H 2 O 2 , dopamine, and nicotinamide adenine dinucleotide, , etc.)…”