Gold Nanoparticle-Containing Membranes from in Situ Reduction of a Gold(III)−Aminoethylimidazolium Aurate Salt

The first example of polycarbonate membranes (PC) modified using layer-by-layer (LBL) adsorption of a polyelectrolyte (PE)/Au NPs system [PE = poly(ethylenimine), PEI; poly(acrylic acid) sodium salt, PAA] in which the Au NPs formation occurs via the in situ postdeposition reduction of the incorporated novel gold(III)−aminoethylimidazolium aurate salt [Cl 3 AuNH 2 (CH 2 ) 2 ImMe)][AuCl 4 ] ( 1 ) is reported. The reduction of 1 to give gold nanoparticles stabilized by an amino-functionalized ionic liquid (ILNH 2 -Au NPs ), was carried out either by the PAA itself during the LBL deposition or by the combined action of PAA and ascorbic acid, the latter added at the end of the deposition process. The different membranes were characterized with AFM, SEM, TEM, UV−vis, and XRD. The XRD analysis revealed that the presence of ILNH 2 caused a remarkable increase of gold nanoparticles with (111) planes parallel to the PC film. The catalytic activity of the modified membranes in the reduction of 4-nitrophenol to 4-aminophenol by NaBH 4 was investigated and found higher than membranes modified with preformed citrate-stabilized gold nanoparticles (citr-Au NPs ) solutions.