| Abstrakt: |
SSx–AMPS–Au nanoparticles were designed and synthesized for use as catalysts in the reductive discoloration of organic dyes. The catalysts are raspberry-like structures consisting of amorphous silica nanoparticle cores, SSx(x = 20, 50 and 100 nm), functionalized with amine groups and decorated with discrete gold nanoparticles. Evaluation of these nano-raspberries for the discoloration of methylene blue in both metal-catalyzed and metal-mediated reactions showed significantly enhanced rates of reduction (< 900 s) as compared to the catalyst-free reactions (> 24 h). Furthermore, the SSx–AMPS–Au nano-raspberries could also successfully reduce a range of anionic and cationic organic dyes, including methyl orange, rhodamine B, congo red, malachite green and crystal violet. The most promising catalyst was SS50–AMPS–Au, which comprized of ~ 3.5 nm gold nanoparticles on a 50 nm silica sphere. SS50–AMPS–Au showed significantly higher activity for all reactions. Comparison of the non-recyclable catalytic system and the recyclable metal-mediated system showed that the catalytic system is the greener of the two. |
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