Enhancing catalytic H2 generation by surface electronic tuning of systematically controlled Pt-Pb nanocrystals

Although many previous studies have show n that the shape-c ontrol of nano crystal(NCs)is an efficient strategy to improve the catalytic performance,these syntheses were conducted under very different conditions,which are not suitable for the shape-dependent properties studies as well as catalysis optimization.Herein,we demonstrate an effective method for the selective synthesis of well-defined PtPb NCs in a highly con trollable mariner.Four disti net PtPb NCs,n amely PtPb pea nut nano crystals,PtPb hexag onal nan opiates,PtPb octahedra nano crystals(ONCs)and PtPb nan oparticles have been selectively prepared in the prese nee of differe nt phe nols.Sign ifica ntly,we found that the created PtPb NCs/C shows the shape-dependent activity with the optimized PtPb ONCs/C being the most active for the ethanol reforming to H2,22.4 times higher than the commercial Pt/C.The high performance of PtPb ONCs/C has been also successfully expanded into other polyhydric alcohols reformings.X-ray photoelectron spectroscopy(XPS)reveals that the high Pt(O)/Pt(ll)ratio in PtPb NCs/C enhances the alcohols reforming.The density functional theory(DFT)studies show the PtPb ONCs possess the highest surface averaged electronic occu patio n for unit Pt-atom,matchi ng well with XPS results.The PtPb ONCs/C also displays excelle nt durability with limited activity decay and negligible structure/composition changes after ten cycles.This work demonstrates an important advance in the high-level control of metallic nanostructures to tune the catalytic activities.