Systematical Tuning Of Ptpb Nanocrystals As Efficient Catalysts For Hydrogen Production

Nowadays,hydrogen?H₂?is considered as a promising potential source of clean energy to efficiently solve the problem of energy shortage and environmental pollution.Unfortunately,its inherent properties make the hydrogen production and handling of H₂gas difficult.In order to solve these restrictions,releasing the required H₂ on-demand from stable liquid offers one way to ensure the safe storage and transportation before use.Among various liquid candidates,methanol?CH₃OH?,a liquid chemical at room temperature and containing 12.6 percent hydrogen,is regarded as a promising material for H₂ storage.However,relatively strict conditions such as high temperatures?over250°C?and high pressures?25-50 bar?are generally needed in the traditional CH₃OH reformation.Moreover,the byproduct of carbon monoxide?CO?,which cannot be tolerated in fuel cells,is unavoidable during the insufficient CH₃OH reformation,largely restricting the practical applications of CH₃OH reformation.Therefore,tremendous attentions for CH₃OH reformation have been focused on designing the catalyst with satisfied activity,high selectivity to H₂ as well as excellent stability.The main target of the water-gas shift?WGS?reaction is to remove the carbon monoxide?CO?formed during the upstream hydrocarbon reforming reaction to increase the H₂ yield as well as the H₂ purity.However,these conventional systems are unsuitable for H₂ generation as required for fuel cell and other applications,because of their space-occupying,time-consuming,and poisoning-susceptibility.Over the past decades,the researches have noticed that platinum?Pt?group noble metals supported on reducible metal oxides,such as zinc oxide?ZnO?,are more active for WGS.Nonetheless,these Pt-based catalysts on reducible supports are not sufficiently stable and progressively deactivate due to the poisoning effect during the reaction.Therefore,tremendous attentions have been focused on enhancing the anti-poisoning ability of Pt-based catalysts towards CO and thereby boosting the activity and durability for WGS.The research is focused on the following aspects:1).we report a new class of two-dimensional?2D?PtPb/Pt core/shell nanodisks with intermetallic PtPb as core and Pt as shell,as highly efficient catalysts for CH₃OH reformation.These Pt-Pb nanodisks are tailored to own unique merits of 2D structure,intermetallic PtPb core and Pt shell,which are highly beneficial for CH₃OH reformation.The optimized 2D core/shell structure exhibits the satisfied CH₃OH reformation activity for H₂ with the outstanding turnover frequency value?TOF?of 3347.2 h^-1,which is 5.1 times higher than the commercial Pt/C(656.2 h^-1).The PtPb/Pt core/shell nanodisks also represent high stability with limited activity decay after ten cycles.The present work highlights the importance of precise tuning of core/shell structure for the design of high-performance heterogeneous catalysts for CH₃OH reformation to produce H₂ and beyond2).we report a top-down strategy to create a new class of porous PtPb NCs?i.e.,porous PtPb peanut NCs?porous PtPb PNCs?and porous PtPb octahedron NCs?porous PtPb ONCs??,as highly efficient catalysts for WGS reaction.In particular,the porous PtPb PNCs-40/ZnO with desirable porous degree exhibits excellent WGS activity with the outstanding turnover frequency value?TOF?of 3730.6 h^-1,16.9 times higher than the commercial Pt/C(220.7 h^-1).The porous PtPb PNCs-40/ZnO also represents high stability with limited activity decay after ten cycles,due to the high anti-poisoning ability of Pb toward CO.We demonstrate an effective solvothermal method for the selective synthesis of well-defined PtPb NCs as the catalyst to investigate the effect of Pb in enhancing the CO anti-poisoning ability of Pt.The present work proposes a new strategy for the design of high-performance Pt catalysts for hydrogen production and beyond.