A Comparison Reduction of 4-Nitrophenol by Gold Nanospheres and Gold Nanostars

In order to investigate structure-property relationships, the catalytic properties of gold nanoparticles were evaluated in the reduction of 4-nitrophenol by NaBH4. Using catalyst suspensions with identical amounts of gold, the following key results were obtained: first, the nanostars showed increased activity as compared to spherical gold nanoparticles; second, larger gold nanostars showed higher activity, likely because of the abundance of flat/spiky features on these particles, which show high metal utilization; third, treatment of the nanostar colloid with cucurbit[7]uril can be used to balance catalyst stability and activity; fourth, as expected from the decreasing surface atom fraction, the specific activity of the spherical nanoparticles decreased with increasing particle size.