Controlled assembly of Ag nanoparticles on the surface of phosphate pillar [6]arene functionalized single-walled carbon nanotube for enhanced catalysis and sensing performance

We developed a green and facile approach for synthesizing Ag@PP6@SWCNT nano-material via in-situ loading silver nanoparticles on the surface of phosphate pillar [6]arene (PP6) functionalized single-walled carbon nanotubes (SWCNT) at room temperature and without using either toxic or organic solvents. Ag nanoparticles (with an average size of 3–4 nm) were uniformly dispersed on the surface of SWCNT via the anchoring effect of PP6. PP6 provided a coordination environment between Ag and –PO₃^2– groups in PP6, and there were the π-π interactions between SWCNT and benzene rings of PP6. The obtained hybrid nano-material Ag@PP6@SWCNT was characterized using UV-vis absorption spectrum, transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Compared to commercial Pd/C and Ag@SWCNT catalysts, Ag@PP6@SWCNT exhibited higher catalytic activity for 4-nitrophenol (4-NP) reduction and methylene blue (MB) degradation, respectively. Moreover, because of the excellent supramolecular host-guest recognition capability of PP6, a sensitive and convenient electrochemical sensing platform for detecting paraquat (PQ) was constructed, and had potential applications in sensing highly toxic herbicides.