Polyelectrolyte Brush Templated Multiple Loading of Pd Nanoparticles onto TiO2 Nanowires via Regenerative Counterion Exchange-Reduction

In this paper, a novel strategy was reported to produce ternary nanocomposite containing TiO2 nanowires, poly [(dimethylamino)ethyl methacrylate] (PDMAEMA) brush and Pd nanoparticles. PDMAEMA brushes were grafted from catecholic initiator anchored on TiO2 nanowires via surface-initiated atom transfer radical polymerization (SI-ATRP) at ambient conditions. The PDMAEMA uniformly covered the surface of TiO2 nanowires and the two component of PDMAEMA and TiO2 shows clear boundary interface. PDMAEMA brushes were derived with CH3I to form quaternized-PDMAEMA (Q-PDMAEMA) so as to facilitate anion exchange with PdCl42-, which was followed by in situ reduction with NaBH4 to obtain the TiO2 nanowires-Q-PDMAEMA/Pd(O) ternary nanocomposite. Pd nanoparticles have very small size of about 2-4nm and monodisperse, uniformly distributed among polymer brush network. Interestingly, after reduction reaction, concurrent with generation of Pd nanoparticles, the ammonium cations were largely recovered, which allows further breath-in PdCl42- counterions and uploads more Pd nanopaticles by repeated steps. The responsivity of both PDMAEMA and Q-PDMAEMA decorated TiO2 nanowires was Studied in response to pH and salt solution. The electrocatalytic behavior of the ternary nanocomposite was investigated.