Au-Ag alloy nanoparticle-incorporated AgBr plasmonic photocatalyst

Ionic liquid-directed synthesis of Au-AgBr Janus nanoparticles via digestive ripening and solvated metal atom dispersion

Multicomponent nanoparticles (MCNs) leverage the synergistic properties of their constituents, offering enhanced performance in diverse applications, including catalysis and photocatalysis. Among them, Janus nanoparticles (JNPs) with their dual domains, stand out as particularly promising. This study presents a novel two-step method to synthesize Au-AgBr JNPs, combining the solvated metal atom dispersion (SMAD) method with digestive ripening (DR). Using ultra-pure metals as precursors negates the need for post-synthesis purification. By adjusting the Au/Ag molar ratio, yields of JNPs up to 85% with precise control of particle size and composition were achieved. The ionic liquid [C18BIm]Br plays a crucial role in promoting AgBr growth on Au nanoparticles, with only low concentrations of ionic liquid favoring Janus structure formation. Additionally, a wet chemical reduction method was also carried out, affording results comparable to those obtained using SMAD and digestive ripening. A mechanistic study for the formation of Au-AgBr JNPs has also been carried out. Driven by a galvanic replacement reaction, the formation mechanism of Au-AgBr JNPs was traced using X-ray photoelectron spectroscopy (XPS). Further, a bromide-free ionic liquid ([C18BIm]NTf2) was also employed for the synthesis which yields AgAu alloy only and no Janus heterostructure formation.

CO2 Conversion in Cu-Pd Based Disordered Network Metamaterials with Ultrasmall Mode Volumes

Plasmons can drive chemical reactions by directly exciting intramolecular transitions. However, strong coupling of plasmons to single molecules remains a challenge as ultrasmall mode volumes are required. In the presented work, we propose Cu-Pd plasmonic network metamaterials as scalable platforms for plasmon-assisted catalysis. Due to the absence of translational symmetry, these networks provide a unique plasmonic environment featuring a large local density of optical states and an unparalleled density of hotspots that effectively localizes light in mode volumes V < 8 × 10-24 m3. Catalytic performance tests during CO2 conversion reveal production rates of up to 4.3 × 102 mmol g-1 h-1 and altered reaction selectivity under light illumination. Importantly, we show that the selectivity of the catalytic process can be tuned by modifying the network's chemical composition, offering a versatile approach to optimize reaction pathways.

A review on plasmonic-based heterojunction photocatalysts for degradation of organic pollutants in wastewater

Organic pollutants in wastewater are the biggest problem facing the world today due to population growth, rapid increase in industrialization, urbanization, and technological advancement. There have been numerous attempts to use conventional wastewater treatment techniques to address the issue of worldwide water contamination. However, conventional wastewater treatment has a number of shortcomings, including high operating costs, low efficiency, difficult preparation, fast recombination of charge carriers, generation of secondary waste, and limited light absorption. Therefore, plasmonic-based heterojunction photocatalysts have attracted much attention as a promising method to reduce organic pollutant problems in water due to their excellent efficiency, low operating cost, ease of fabrication, and environmental friendliness. In addition, plasmonic-based heterojunction photocatalysts contain a local surface plasmon resonance that enhances the performance of photocatalysts by improving light absorption and separation of photoexcited charge carriers. This review summarizes the major plasmonic effects in photocatalysts, including hot electron, local field effect, and photothermal effect, and explains the plasmonic-based heterojunction photocatalysts with five junction systems for the degradation of pollutants. Recent work on the development of plasmonic-based heterojunction photocatalysts for the degradation of various organic pollutants in wastewater is also discussed. Lastly, the conclusions and challenges are briefly described and the direction of future development of heterojunction photocatalysts with plasmonic materials is explored. This review could serve as a guide for the understanding, investigation, and construction of plasmonic-based heterojunction photocatalysts for various organic pollutants degradation.

GRAPHICAL ABSTRACT

Herein, the plasmonic effects in photocatalysts, such as hot electrons, local field effect, and photothermal effect, as well as the plasmonic-based heterojunction photocatalysts with five junction systems for the degradation of pollutants are explained. Recent work on plasmonic-based heterojunction photocatalysts for the degradation of various organic pollutants in wastewater such as dyes, pesticides, phenols, and antibiotics is discussed. Challenges and future developments are also described.

Plasmonic Hybrid Nanostructures in Photocatalysis: Structures, Mechanisms, and Applications

(Sun)Light is an abundantly available sustainable source of energy that has been used in catalyzing chemical reactions for several decades now. In particular, studies related to the interaction of light with plasmonic nanostructures have been receiving increased attention. These structures display the unique property of localized surface plasmon resonance, which converts light of a specific wavelength range into hot charge carriers, along with strong local electromagnetic fields, and/or heat, which may all enhance the reaction efficiency in their own way. These unique properties of plasmonic nanoparticles can be conveniently tuned by varying the metal type, size, shape, and dielectric environment, thus prompting a research focus on rationally designed plasmonic hybrid nanostructures. In this review, the term "hybrid" implies nanomaterials that consist of multiple plasmonic or non-plasmonic materials, forming complex configurations in the geometry and/or at the atomic level. We discuss the synthetic techniques and evolution of such hybrid plasmonic nanostructures giving rise to a wide variety of material and geometric configurations. Bimetallic alloys, which result in a new set of opto-physical parameters, are compared with core-shell configurations. For the latter, the use of metal, semiconductor, and polymer shells is reviewed. Also, more complex structures such as Janus and antenna reactor composites are discussed. This review further summarizes the studies exploiting plasmonic hybrids to elucidate the plasmonic-photocatalytic mechanism. Finally, we review the implementation of these plasmonic hybrids in different photocatalytic application domains such as H₂ generation, CO₂ reduction, water purification, air purification, and disinfection.