A simple pH-sensitive P(acrylamide-co-acrylic acid) copolymer was employed as a stabilizer for Pd nanoparticles (NPs) to develop a recyclable and highly efficient catalyst system. P(AAm-co-AA) copolymer stabilized Pd NPs exhibited high activity in the aqueous hydrogenation of allyl alcohol (HA) and phenol (HP). After reaction, due to the pH-sensitive property of P(AAm-co-AA), the P(AAm-co-AA)-Pd catalyst can be easily separated from the reaction medium by simply adjusting pH from weak basic condition (pH > 8) to acidic condition (pH < 3). Only negligible activity loss was found in the following catalytic runs. (C) 2017 Published by Elsevier B.V.