Enhanced photocatalytic performance of SnS2 under visible light irradiation: strategies and future perspectives

Tin(II) sulfide (SnS2) has emerged as a promising candidate for visible light photocatalytic materials. As a member of the transition metal dichalcogenides (TMDs) family, SnS2 features a band gap of approximately 2.20 eV and a layered structure, rendering it suitable for visible light activation with a high specific surface area. However, the application of SnS2 as a visible light photocatalyst still requires improvement, particularly in addressing the high recombination of electrons and holes, as well as the poor selectivity inherent in its perfect crystal structure. Therefore, ongoing research focuses on strategies to enhance the photocatalytic performance of SnS2. In this comprehensive review, we analyze recent advances and promising strategies for improving the photocatalytic performance of SnS2. Various successful approaches have been reported, including controlling the reactive facets of SnS2, inducing defects in the crystal structure, manipulating morphologies, depositing noble metals, and forming heterostructures. We provide a detailed understanding of these phenomena and the preparation techniques involved, as well as future considerations for exploring new science in SnS2 photocatalysis and optimizing performance.

Integration of oxygen vacancies into BiOI via a facile alkaline earth ion-doping strategy for the enhanced photocatalytic performance toward indometacin remediation

Bismuth oxyiodide (BiOI) has garnered intense attention in the field of photocatalysis for environmental remediation; however, it suffers from a high electron-hole recombination rate. In this study, for the first time, we report on a facile strategy for the creation of oxygen vacancies in BiOI via strontium (Sr²⁺) doping. The as-prepared 0.45-SrBiOI demonstrated significantly enhanced photocatalytic degradation of indometacin under visible light exposure, which was almost 10 folds higher than pristine BiOI. This augmented photocatalytic performance was ascribed to the accelerated separation of charge carriers by oxygen vacancies, as well as Sr ion trapping electrons. Reactive species determination experiments revealed that O₂^▪-, ¹O₂, and h⁺ were the dominant active species. Finally, potential indometacin degradation pathways were proposed based on the identification of degradation by-products and theoretical calculations. This study offers new perspectives for the synthesis of highly efficient and cost effective BiOI-based photocatalysts, and provides a promising strategy toward advanced environmental remediation.

Fabrication of a novel BiOI/KTaO3 p-n heterostructure with enhanced photocatalytic performance under visible-light irradiation

In this study, a series of BiOI/KTaO3 p-n heterojunctions were prepared via a facile in situ chemical bath strategy. The photocatalytic properties of the catalysts was tested by the degradation of Rhodamine B (RhB) and phenol under visible light irradiation. The BiOI/KTaO3 composites exhibited improved photocatalytic efficiency compared to the individual catalysts. In particular, 54 wt% BiOI/KTaO3 displayed the highest photocatalytic activity since it degraded 98.6% RhB within 30 minutes, while only 68.1% RhB was degraded over pure BiOI under identical conditions. In addition, the reaction kinetic constant of RhB degradation over 54 wt% BiOI/KTaO3 was approximately 2.56 and 115-fold larger than those of pure BiOI and KTaO3, respectively. The results of PL, photocurrent and EIS indicated that the improved photocatalytic efficiency could root in the p-n junction formed between BiOI and KTaO3, which was conducive to the separation and migration of photo-generated carriers. Furthermore, a free-radical capture experiment illustrated that h+ and ˙O2 - were the key factors in the photodegradation of RhB.

Enhancement of Solar-Driven Photocatalytic Activity of BiOI Nanosheets through Predominant Exposed High Energy Facets and Vacancy Engineering

The increasing application of exposed high energy facet is an effective strategy to improve the photocatalytic performance of photocatalysts because the vacancies are beneficial to photocatalytic reaction. Vacancy dominates numerous distinct properties of semiconductor materials and thus plays a conclusive role in the photocatalysis applications. In this work, two kinds of BiOI nanomaterials with different vacancies are synthesized via a facile solvothermal method. The positron annihilation analysis shows that the thinner BiOI nanosheets possess larger-sized vacancy than BiOI nanoplates. Thus, BiOI nanosheets show the enhanced separation efficiency of electron-hole pairs and adsorption ability for contaminants under visible light. The results are also validated with the first-principle computation. Therefore, higher photocatalytic activity to the photodegradation of tetracycline is observed from the nanosheets than that obtained from BiOI nanoplates. This work not only arouses attention to vacancies, but also opens up an avenue for precision design of vacancies to prepare novel photocatalytic materials driven under solar light.

Heterostructural design of I-deficient BiOI for photocatalytic decoloration and catalytic CO2 conversion

I⁻ vacancies in BiOI play a major role in governing the photocatalysis and catalysis.

In situ fabrication of two-dimensional g-C3N4/Ba5Ta4O15 nanosheet heterostructures with efficient charge separations and photocatalytic hydrogen evolution under visible light illumination

Separation of photo-generated electron-hole pairs plays a crucial role in determining the practical performance of semiconductor photocatalysts. Here we have successfully fabricated two dimensional g-C₃N₄/Ba₅Ta₄O₁₅ nanosheet heterostructures through an in situ urea degradation method. The so-formed nanosheet heterostructures demonstrate superior photocatalytic activities in H₂ evolution reactions over individual component. Further analysis using photoelectrochemical measurements suggests efficient charge separations at the interfaces of these heterostructures which contribute to a prolonged lifetime of photo-generated charges as well as the much enhanced photocatalytic activities. The in situ fabrication method adopted in this work ensures a firm anchorage of g-C₃N₄ onto Ba₅Ta₄O₁₅ nanosheets and a face-to-face contact between these two semiconductors. Such a peculiar microstructure is critical to the high photocatalytic activity and apparently outweighs the conventional ones that involve only physical mixtures of two semiconductors and a point-to-point contact.

Novel Ag2S quantum dot modified 3D flower-like SnS2 composites for photocatalytic and photoelectrochemical applications

Novel Ag₂S quantum dot modified 3D flower-like SnS₂ composites exhibit highly efficient photodegradation of MO and photocatalytic H₂ production.

Highly interdigitated and porous architected ternary composite of SnS2, g-C3N4, and reduced graphene oxide (rGO) as high performance lithium ion battery anodes

Highly interdigitated and porous architected ternary composites of SnS₂, rGO and g-C₃N₄ synthesized via one-pot hydrothermal route showed excellent electrochemical properties.

Efficient charge separation based on type-II g-C3N4/TiO2-B nanowire/tube heterostructure photocatalysts

Separation of photo-generated charges has played a crucial role in controlling the actual performance of a photocatalytic system. Here we have successfully fabricated g-C3N4/TiO2-B nanowire/tube heterostructures through facile urea degradation reactions. Owing to the effective separation of photo-generated charges associated with the type-II band alignment and intimate interfacial contacts between g-C3N4 and TiO2-B nanowires/tubes, such heterostructures demonstrate an improved photocatalytic activity over individual moieties. Synthetic conditions such as hydrothermal temperatures for the preparation of TiO2-B and the weight ratio of TiO2-B to urea were systematically investigated. A high crystallinity of TiO2-B as well as the proper growth of g-C3N4 on its surface are critical factors for a better performance. Our simple synthetic method and the prolonged lifetime of photo-generated charges signify the importance of type-II heterostructures in the photocatalytic applications.

BiOI solar cells

An inorganic solar cell was constructed using a thin compact supporting layer of titania with BiOI nanoflakes as a functional material, a Pt/FTO cathode and a I₃⁻/I⁻ redox electrolyte.