A Recycling-Free Nanocatalyst System: The Stabilization of In Situ-Reduced Noble Metal Nanoparticles on Silicone Nanofilaments via a Mussel-Inspired Approach (Retracted article. See vol. 8, pg. 5023, 2018)

摘要

The recovery and reuse of costly nanocatalysts is an essential operation in modern nanocatalysis, and improvements in catalyst reusability can contribute significantly to the economic viability and sustainable development of nanocatalysis. Herein, starting with the application of a silicone nanofilament (SNF) coating on a target substrate, a mussel-inspired approach in the form of polydopamine (PDA) deposition on the SNF surface was used to form in situ-reduced Pd nanoparticles (Pd NPs) and to stabilize them on the SNFs. This PDA-mediated approach enabled a high integrity nanocatalyst system to be built on a free-standing SNF support while retaining the porosity in the original SNF architecture. The SNFs-Pd nanocomposites prepared as such were applied to the inside walls of laboratory chemical reactors and used as recycling-free nanocatalyst systems for Pd-catalyzed organic reactions without the laborious conventional catalyst recovery and redispersion processes. The SNFs-Pd catalyst system exhibited high activity and high selectivity in single and successive Heck coupling reactions; and a reusability as high as 90% was still possible in the 20th cycle. This mussel-inspired approach is highly versatile and can be applied to laboratory chemical reactors in different shapes, sizes, and configurations to scale up the nanocatalyst applications. Furthermore, the general utility of the chemistry involved allows this surface modification technique to apply to other supported noble metal (e.g., Ag, Au, and Pt) catalysts, thereby increasing the usability and the performance of nanocatalyst systems.