Synthesis of Au–Ag Alloy Nanoparticle-Incorporated AgBr Crystals

Catalysts

Hiroaki Tada¹  Shin-ichi Naya¹  Musashi Fujishima² 

[1] Environmental Research Laboratory, Kindai University, 3-4-1, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan;Graduate School of Science and Engineering, Kindai University, 3-4-1, Kowakae, Higashi-Osaka, Osaka 577-8502, Japan;

关键词: silver halide;    silver–gold alloy nanoparticle;    local electric field enhancement;    plasmonic photocatalyst;   

DOI  :  10.3390/catal9090745

来源: DOAJ

【 摘 要 】

Nanoscale composites consisting of silver and silver halide (Ag−AgX, X = Cl, Br, I) have attracted much attention as a novel type of visible-light photocatalyst (the so-called plasmonic photocatalysts), for solar-to-chemical transformations. Support-free Au−Ag alloy nanoparticle-incorporated AgBr crystals (Au−Ag@AgBr) were synthesized by a photochemical method. At the initial step, Au ion-doped AgBr particles were prepared by adding an aqueous solution of AgNO₃ to a mixed aqueous solution of KBr and HAuBr₄. At the next step, UV-light illumination (λ = 365 nm) of a methanol suspension of the resulting solids yielded Au−Ag alloy nanoparticles with a mean size of approximately 5 nm in the micrometer-sized AgBr crystals. The mole percent of Au to all the Ag in Au−Ag@AgBr was controlled below < 0.16 mol% by the HAuBr₄ concentration in the first step. Finite-difference time-domain calculations indicated that the local electric field enhancement factor for the alloy nanoparticle drastically decreases with an increase in the Au content. Also, the peak of the localized surface plasmon resonance shifts towards longer wavelengths with increasing Au content. Au−Ag@AgBr is a highly promising plasmonic photocatalyst for sunlight-driven chemical transformations due to the compatibility of the high local electric field enhancement and sunlight harvesting efficiency.

【 授权许可】

Unknown