Easily recyclable and highly active rice roll-like Au/SiO2 nanocatalysts from inverse miniemulsion

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 517; pp. 52 - 62
• Main Authors: Cao, Zhihai, Chen, Hangnan, Shang, Yi, Zhang, Yushan, Qi, Dongming, Ziener, Ulrich
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20-03-2017
• Subjects: Au/SiO2 nanocatalysts; Inverse miniemulsion; Particle morphology; pH-dependent colloidal stability; Au/SiO2 nanocatalysts; Inverse miniemulsion; pH-dependent colloidal stability; Particle morphology
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2017.01.010

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•Rice roll-like Au/SiO2 nanocatalysts were synthesized through one-step inverse miniemulsion-based technique.•The rice roll-like Au/SiO2 nanocatalysts embody excellent catalytic activity and good recycling catalytic performance.•The rice roll-like Au/SiO2 nanocatalysts display good aqueous dispersibility and pH-dependent, reversible colloidal stability.•A formation mechanism of rice roll-like Au/SiO2 nanocatalysts was proposed.
Rice roll-like (RR-like) Au/SiO2 nanocatalysts (NCs) were synthesized through simultaneous sol–gel process of tetramethoxysilane and 3-aminopropyltriethoxysilane (APTES) and in situ reduction of gold salt in inverse miniemulsions. APTES played an important role in formation of RR-like SiO2 nano-supports, reduction of gold salts to narrowly size-distributed sub–10nm Au nanoparticles (NPs), and improved attachment of Au NPs to the SiO2 nano-supports. The prepared RR-like Au/SiO2 NCs displayed a pH-dependent, reversible colloidal stability in water, which facilitated to recycle them through tuning the pH value of the dispersion. Most importantly, the catalytic activity of the RR-like Au/SiO2 NCs towards reduction of p-nitrophenol was about 7–9 times higher than that of the raspberry-like Au/SiO2 NCs reported in our previous paper (Colloids Surf. A, 489, 2016, 223–233). The formation mechanism of the RR-like Au/SiO2 NCs was also discussed.