Porous poly(ether sulfone) (PES) microfiber mat has been prepared by electrospinning technique using the optimized conditions. The reducing moiety has been attached covalently to the PES microfiber mat by UV-graft polymerization of glycidylmethacrylate, and reacting subsequently with hydrazine via epoxy ring opening. The grafted polymer shell around porous microfiber has been found to perform the reduction of precursor ions by grafted hydrazine which leads to the nucleation and growth of Pd nanoparticles (NPs) on the host matrix itself. The catalytic activities and reduction kinetics of the microfiber hosted Pd NPs have been examined in the reductions of Cr-VI and U-VI ions with in situ hydrogen generated by the formic acid decomposition at 50 degrees C, and p-nitrophenol with borohydride/hydrazine at room temperature. Thus, hosted Pd NPs exhibit higher catalytic activity with respect to that reported in literature, and also the host matrix provides reasonably good recyclability and shelf-life to Pd NPs.