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.

Efficient catalytic hydrogen generation by intermetallic platinum-lead nanostructures with highly tunable porous feature

The water-gas shift(WGS) reaction is an essential industrial reaction for upgrading hydrogen(H2) by removing carbon monoxide(CO), while highly efficient platinum(Pt)-based catalysts for WGS with simultaneously high activity and stability are still yet to be developed due to the poisoning issue during the reaction. Herein, we report on the porous PtPb peanut nanocrystals(porous PtPb PNCs) and porous PtPb octahedron nanocrystals(porous PtPb ONCs) with controllable ratios of Pt/Pb as extremely active and stable catalysts towards WGS reaction. It exhibits the composition-dependent activity with porous PtPb PNCs-40/ZnO being the most active for WGS to H_2, 16.9 times higher than that of the commercial Pt/C. The porous PtPb PNCs-40/ZnO also display outstanding durability with barely activity decay and negligible structure and composition changes after ten successive reaction cycles. X-ray photoelectron spectroscopy(XPS) results reveal that the suitable binding energy of Pt 4f_(7/2) and the high ratio of Pt(0)to Pt(II) in porous PtPb PNCs/ZnO and porous PtPb ONCs/ZnO are crucial for the enhanced WGS activity.The CO stripping results indicate the optimized CO adsorption strength on the Pt surface ensure the excellent WGS activity and the outstanding durability. The present work demonstrates an important advance in tuning the porous metal nanomaterials as highly efficient and durable catalysts for catalysis,energy conversion and beyond.