Sim Sangwan, Beierle Alyssa, Mantos Philip, McCrory Steven, Prasankumar Rohit P, Chowdhury Sanchari
Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Nanoscale. 2020 May 14;12(18):10284-10291. doi: 10.1039/d0nr00831a.
Combining a plasmonic metal, such as gold, with other popular catalysts, such as Ni or Pt, can extend its benefits to many energy-extensive reactions catalyzed by those metals. The efficiency of a plasmon-enhanced catalytic reaction is mainly determined by the light absorption cross section and the photoexcited charge carrier relaxation dynamics of the nanoparticles. We have investigated the charge carrier relaxation dynamics of gold/nickel (Au/Ni) and gold/platinum (Au/Pt) bimetallic nanoparticles. We found that the addition of Ni or Pt to gold can reduce light absorption in gold nanoparticles. However, electron-phonon coupling rates of Au/Ni and Au/Pt nanoparticles are significantly faster than that of pure Au nanoparticles. This is due to the fact that both Ni and Pt possess significantly larger electron-phonon coupling constants and higher densities of states near the Fermi level in comparison with Au. Additionally, the phonon-phonon coupling rate of bimetallic Au/Pt and Au/Ni nanoparticles was significantly different from that of pure gold nanoparticles, due to the acoustic impedance mismatch at the nanoparticle/substrate interface. Our findings provide important insights into the rational design of bimetallic plasmonic catalysts.
将诸如金等等离子体金属与其他常用催化剂（如镍或铂）相结合，可将其优势扩展至由这些金属催化的许多耗能大的反应中。等离子体增强催化反应的效率主要由纳米颗粒的光吸收截面和光激发电荷载流子弛豫动力学决定。我们研究了金/镍（Au/Ni）和金/铂（Au/Pt）双金属纳米颗粒的电荷载流子弛豫动力学。我们发现，向金中添加镍或铂会降低金纳米颗粒的光吸收。然而，Au/Ni和Au/Pt纳米颗粒的电子 - 声子耦合速率明显快于纯金纳米颗粒。这是因为与金相比，镍和铂都具有明显更大的电子 - 声子耦合常数以及费米能级附近更高的态密度。此外，由于纳米颗粒/基底界面处的声阻抗失配，双金属Au/Pt和Au/Ni纳米颗粒的声子 - 声子耦合速率与纯金纳米颗粒的显著不同。我们的研究结果为双金属等离子体催化剂的合理设计提供了重要见解。
