title: Size effect of gold nanoparticles in catalytic reduction of p-nitrophenol with NaBH4.
abstract: Gold nanoparticles (Au NPs) were prepared by reducing HAuCl4 with NaBH4. Their average particle sizes could be tuned in the range of 1.7 and 8.2 nm, by adjusting the amount of NaBH4 used during synthesis. The obtained Au NPs (colloids) were then loaded onto a commercial Al2O3 support to prepare Au/Al2O3 catalysts with tunable Au particle sizes. An optimal pH value (5.9) of the Au colloid solution was found to be essential for loading Au NPs onto Al2O3 while avoiding the growth of Au NPs. Au NPs and Au/Al2O3 catalysts were tested in the reduction of p-nitrophenol with NaBH4. Interestingly, the catalytic activity depended on the size of Au NPs, being the highest when the average size was 3.4 nm. Relevant characterization by UV-Vis, TEM, and XRD was conducted.
authors.affiliation: Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, China. huadayin@nbu.edu.cn.
authors.forename: Chao
authors.initials: C
authors.lastname: Lin
authors.forename: Kai
authors.initials: K
authors.lastname: Tao
authors.forename: Dayin
authors.initials: D
authors.lastname: Hua
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ma
authors.forename: Shenghu
authors.initials: S
authors.lastname: Zhou
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D001894:Borohydrides / Q000737:chemistry*; D002384:Catalysis; D003102:Colloids; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D009596:Nitrophenols / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D019163:Reducing Agents / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction
chemical_list: D001894:Borohydrides; D003102:Colloids; D009596:Nitrophenols; D019163:Reducing Agents; D006046:Gold; C025364:sodium borohydride; D000537:Aluminum Oxide; C024836:4-nitrophenol