Effect of silver doping on the properties and photocatalytic performance of In2S3 nanoparticles

A facile synthesis of highly efficient In2S3 photocatalysts for the removal of cationic dyes with size-dependent photocatalysis

In this study, a 3D thornball-like hierarchical β-In₂S₃, displaying extremely rapid photodegradation of cationic dyes, was synthesized by a facile method. The formation of a uniform thornball-like structure depended on the microwave reaction method and citric acid as the pH regulator. The size of In₂S₃ was easily adjusted by changing the microwave irradiation time from 5 min to 15 min. The morphology, structure, composition, energy level, charge separation, and surface properties of different-sized In₂S₃ were characterized. The results showed that In₂S₃ synthesized in 10 min (In₂S₃-10) displayed optimal interface property for the electron-hole separation, maximum hydrophilia with most surface negative charges for the surface adsorption, contributing to the complete photodegradation of rhodamine B (RhB) in just 25 minutes of visible light illumination. The photodegradation path of RhB was speculated with four possible paths, including the processes of de-ethylation, open-ring of xanthene, and rupture of carbon-carbon bonds up to the decomposition into small molecules. Finally, the reusability of In₂S₃-10 was tested, obtaining nearly 96% photodegradation efficiency after sequential 5 cycles.

One-pot solvothermal synthesis of flower-like Fe-doped In2S3/Fe3S4 S-scheme hetero-microspheres with enhanced interfacial electric field and boosted visible-light-driven CO2 reduction

S-scheme heterojunctions hold great potential for CO2 photoreduction into solar fuels, but their activities are severely limited by the low efficiency of interfacial charge transfer. In this work, a facile one-pot solvothermal reaction has been developed to dope Fe into flower-like In2S3/Fe3S4 hetero-microspheres (Fe-In2S3/Fe3S4 HMSs), which are demonstrated as an efficient S-scheme photocatalyst for visible-light-driven CO2 photoreduction. The doping of Fe not only reduces the bandgap of In2S3 and thus extends the optical response to the visible-light region, but also increases the densities of donors and sulfur vacancies, which leads to an elevated Fermi level (Ef). The difference of Ef between In2S3 and Fe3S4 is enlarged and their band bending at the interface is therefore enhanced, which results in promoted carriers transfer in the S-scheme pathway due to the reinforced interfacial electric field. Moreover, Fe-doped In2S3 reduces the formation energy of the *CO intermediate, which thermodynamically favors the CO evolution at the surface. As a result, the Fe-In2S3/Fe3S4 HMSs exhibit a significantly boosted CO2 photoreduction activity in comparison with bare In2S3 and Fe-In2S3 samples. This work demonstrates the great potential of heteroatom-engineered S-scheme photocatalysts for CO2 photoreduction.

Nano-Ag: Environmental applications and perspectives

Silver nanoparticles (AgNPs) are promising bactericidal agents and plasmonic NPs for environmental applications, owing to their various favorable properties. For example, AgNPs enables reactive oxygen species (ROS) generation, surface plasmon resonance (SPR), and specific reaction selectivities. In fact, AgNPs-based materials and their antimicrobial, optical, and electrical effects are at the forefront of nanotechnology, having applications in environmental disinfection, elimination of environmental pollutants, environmental detection, and energy conversions. This review aims to comprehensively summarize the advanced applications and fundamental mechanisms to provide the guidelines for future work in the field of AgNPs implanted functional materials. The state-of-art terms including (photo)(electro)catalytic reactions, heterojunction formation, the generation and attacking of ROS, genetic damage, hot electron generation and transfer, localized surface plasmon resonance (LSPR), plasmon resonance energy transfer (PERT), near field electromagnetic enhancement, structure-function relationship, and reaction selectivities have been covered in this review. It is expected that this review may provide insights into the rational development in the next generation of AgNPs-based nanomaterials with excellent performances.