Sandwich-structured MXene@Au/polydopamine nanosheets with excellent photothermal-enhancing catalytic activity

Local surface plasmon resonance (LSPR) of noble metal nanoparticles plays a significant role in nanocatalysis via directly harvesting optical energy from resonant light. However, the photothermally-assistant catalytic application is limited due to the narrow visible/infrared absorption range and low photothermal conversion efficiency. Herein, a sandwich-structured MXene@Au/Polydopamine (PDA) nanosheet with good hydrophilicity, large specific surface area and tri-photothermal components is developed for nanocatalysis. The Au/PDA hybrid shells are covered on the MXene nanosheets via a simple one-step redox-oxidize polymerization method. As a result, the catalytic dynamic of MXene@Au/PDA nanosheets on reducing 4-nitrophenol reaches to 0.28 min⁻¹·mg⁻¹, which is about 2 times larger than that of the nanocatalysts without NIR light irradiation. Owing to the well protection of PDA shell, after 10 cycles of reduction of 4-nitrophenol, MXene@Au/PDA nanosheets still maintain more than 90% activity. This work in depth insights into NIR light-assistant avenue to enhance the catalytic activity of noble metal nanocatalysts and highlights an easy synthetic model for heterogeneous catalysts based on MXene nanocomposites.