Four types of new multi-walled carbon nanotube (MWCNT) based nanohybrid catalysts were prepared through simple methods. Initially, MWCNT was functionalized with carboxyl group and subsequently bonded with amphiphilic poly(propyleneimine) dendrimer (APPI) having generation (G2) and (G3). They are abbreviated as MWCNT-APPI (G2) and MWCNT-APPI (G3). Silver nanoparticles (AgNPs) and palladium nanoparticles (PdNPs) were separately immobilized to each hybrid to obtain four types of MWCNT based nanohybrid catalysts. The pseudo-first order rate constants for reduction of 4-nitrophenol revealed that among the four types of MWCNT nanohybrid catalysts, MWCNT-APPI (G3)-PdNPs was more efficient than the other catalysts with five-fold higher efficiency than the homogeneous PPI (G3)-PdNPs. For the same reaction with MWCNTs-APPI (G3)-PdNPs catalyst, the variation of [catalyst] and [NaBH4] was directly proportional to k(obs). The study of reusability of MWCNT-APPI (G3)-PdNPs proved no loss in activity even after recycling the catalyst for five times. (C) 2013 Elsevier Inc. All rights reserved.