AgPd nanocages sandwiched between a MXene nanosheet and PDA layer for photothermally improved catalytic activity and antibacterial properties.

In this work, a MXene@AgPd/polydopamine (PDA) nanosheet with excellent photothermal conversion efficiency was successfully synthesized by a simple redox-oxidative polymerization method. Interestingly, AgPd bimetallic nanocrystals sandwiched between a MXene nanosheet and PDA layer have cage-like nanostructure, which is favorable for high catalytic efficiency and antibacterial performance. Importantly, the MXene@AgPd/PDA nanosheet exhibits good catalytic activity for the reduction of 4-nitrophenol (1.2 min -1 mg -1 ) and the catalytic dynamics can be improved by about 1.2 times under NIR (near-infrared light, 808 nm, and 2.5 W cm -2 ) irradiation. As the PDA shell is well protected, the MXene@AgPd/PDA nanosheet retained more than 90% catalytic activity after 6 cycles. In addition, due to the presence of the Ag component, the MXene@AgPd/PDA nanosheet exhibited good antibacterial activity against both Gram-negative ( E. coli ) and Gram-positive ( S. aureus ) bacteria. Under near-infrared light irradiation, its antibacterial activity was further enhanced due to the NIR photothermal effect.