Bobb Julian A, Rodrigues Collin J, El-Shall M Samy, Tibbetts Katharine Moore
Department of Chemistry, Virginia Commonwealth University, Richmond, VA 23284, USA.
Phys Chem Chem Phys. 2020 Sep 7;22(33):18294-18303. doi: 10.1039/d0cp02953j. Epub 2020 Aug 12.
Laser photoreduction of metal ions onto graphene oxide (GO) is a facile, environmentally friendly method to produce functional metal-GO nanocomposites for a variety of applications. This work compares Au-GO nanocomposites prepared by photoreduction of [AuCl] in aqueous GO solution using laser pulses of nanosecond (ns) and femtosecond (fs) duration. The presence of GO significantly accelerates the [AuCl] photoreduction rate, with a more pronounced effect using ns laser pulses. This difference is rationalized in terms of the stronger interaction of the 532 nm laser wavelength and long pulse duration with the GO. Both the ns and fs lasers produce significant yields of sub-4 nm Au nanoparticles attached to GO, albeit with different size distributions: a broad 5.8 ± 1.9 nm distribution for the ns laser and two distinct distributions of 3.5 ± 0.8 and 10.1 ± 1.4 nm for the fs laser. Despite these differences, both Au-GO nanocomposites had the same high catalytic activity towards p-nitrophenol reduction as compared to unsupported 4-5 nm Au nanoparticles. These results point to the key role of GO photoexcitation in catalyzing metal ion reduction and indicate that both ns and fs lasers are suitable for producing functional metal-GO nanocomposites.
通过激光将金属离子光还原到氧化石墨烯（GO）上，是一种简便、环保的方法，可制备用于多种应用的功能性金属-GO纳米复合材料。这项工作比较了使用纳秒（ns）和飞秒（fs）持续时间的激光脉冲，在水性GO溶液中通过[AuCl]的光还原制备的Au-GO纳米复合材料。GO的存在显著加速了[AuCl]的光还原速率，使用ns激光脉冲时效果更明显。这种差异可以从532 nm激光波长和长脉冲持续时间与GO的更强相互作用来解释。ns和fs激光都产生了大量附着在GO上的亚4 nm金纳米颗粒，尽管尺寸分布不同：ns激光的分布较宽，为5.8±1.9 nm，fs激光有两个不同的分布，分别为3.5±0.8和10.1±1.4 nm。尽管存在这些差异，但与无载体的4-5 nm金纳米颗粒相比，两种Au-GO纳米复合材料对对硝基苯酚还原都具有相同的高催化活性。这些结果表明GO光激发在催化金属离子还原中起关键作用，并表明ns和fs激光都适用于制备功能性金属-GO纳米复合材料。
