Heterogeneous form of poly (4-vinyl pyridine) beads based dendrimer stabilized Ag, Au and PdNPs catalyst for reduction of trypan blue

Poly(styrene)-co-poly(4-vinyl pyridine) (PS-P4VP) beads were prepared by suspension polymerization technique. PPI(G2) and PPI(G3) dendrimers were grafted on the surface of PS-P4VP beads and were two types of polymer supports viz., PS-P4VP-PPI(G2) and PS-P4VP-PPI(G3). Further, these above two different matrices were used to prepare six types of heterogeneous nanoparticle catalysts viz., PS-P4VP-PPI(G2)-AgNPs, PS-P4VP-PPI(G2)-AuNPs, PS-P4VP-PPI(G2)-PdNPs, PS-P4VP-PPI(G3)-AgNPs, PS-P4VP-PPI(G3)-AuNPs and PS-P4VP-PPI(G3)-PdNPs and AgNO3, HAuCl3 and K2PdCl4 as a metal precursor. The prepared catalysts were characterized by FTIR, UV–Vis, FESEM/EDAX and HRTEM to find the functional group and surface morphology of the catalysts. The catalytic efficiency of the heterogenous nanoparticle catalysts was studied by reduction of trypan blue (TB). The obtained kobs values explain that it to increase the generation numbers/active sites have been used to enhance the metal loading. On comparing the Ag, Au and PdNPs, the AuNPs immobilized beads are an outstanding catalytic activity because of high reduction potential. Especially, the PPI(G3) dendrimer stabilized AuNPs have higher catalytic efficiency, because the PPI(G3) dendrimer contains a greater number of surface amino groups stabilized the higher amount of AuNPs and increase the dendrimer generation (PPI(G2)–PPI(G3)) the particle size also reduced. Keywords: Poly(4-vinylpyridine), Dendrimer, Heterogeneous nanoparticles, Trypan blue