Precious Metal Nanoparticles Supported On Selenium Functionalized Carbon As Electrocatalyst Towards Small Molecules Electrocatalytic Oxidation

Electrocatalyst is an important component of fuel cells.However,due to high price and low stability of noble metal electrocatalyst,the commercialization process of fuel cells is limited seriously.Therefore,exploring a newly precious metal and non-precious metal electrocatalyst with high activity and stability,as well as an electrocatalyst with a novel support,is extremely significant in the application and development of fuel cells.Noteworthily,the novel support has good prospect for fabricating efficacious electrocatalyst.It not noly could act as a co-catalyst to improve the electrocatalytic performance of noble metal,but also enhance the stability.Recently,the exploitation of a new-type carbon-based material by heteroatom-doped/codoped as electrocatalyst support have been attracted much atttention in the field of electrocatalysis.However,less attention has been paid to develop selenium?Se?functionalized carbon support by heteroatom-doping.Due to Se possesses special chemical properties,therefore,it is an practicable strategy to achieve the commercialization of fuel cells by introducing Se into support material to form an efficacious anode electrocatalyst.This study mainly focuses on the synthesis of high efficiency and low cost a novely support anode electrocatalysts for fuel cells.By doping heteroatom Se as a principal line,and combinating the electronic effect of N and P to construct an codoped carbon support material.Generaly,selenium functionalized carbon can tailor the surface electronic structure by the introduction of heteroatom into sp²-hybridized carbon frameworks.This is an effective support to immobilize nanoparticles?NPs?to produce efficient electrocatalysts,as well as an promising material to improve catalytic performance.In this work,the structures of as-prepared electrocatalysts were characterized by physical tests.Simultaneously,their electrocatalytic performance for glucose,ethylene glycol and glycerol electroxidation was also studied by electrochemical test methods.The thesis consists of three parts as follows:Part I:Selenium functionalized carbon Combined Pd₃Sn alloy NPs towards glucose oxidationTo combine with the advantages of selenium functionalized carbon and bimetallic-alloy NPs,a novel Se-C supported Pd₃Sn?Pd₃Sn/Se-C?electrocatalyst was successfully prepared and estimated towords glucose oxidation reaction?GOR?in alkaline medium.The results demonstrate that Pd₃Sn/Se-C electrocatalyst possesses superior catalytic performance towards GOR.Specifically,it presents larger electrochemically active surface area?EASA?,higher electrocatalytic activity and better cycling stability compared to those of Pd₃Sn/C,Pd/Se-C and Pd/C.This satisfactory result mainly owes to the special properties of selenium functionalized carbon material,as well as the synergetic effect between Pd₃Sn alloy NPs and Se-C support.Posterior,the thermodynamic study reveals that the Pd₃Sn/Se-C electrocatalyst has lower activation energy?Ea?than that of Pd/C,leading to a less energy barrier towards GOR.The investigation of novel Se-C support in this study would provide a new avenue to develop some excellent electrocatalysts.Part II:A N-Se-C support anchoring Pd NPs towards ethylene glycol electrooxidationAn electrocatalyst of novel N and Se codoped-carbon?N-Se-C?support anchoring Pd NPs?Pd/N-Se-C?has been fabricated and evaluated towards ethylene glycol electrooxidation?EGOR?.Notably,the N and Se codoped-carbon support makes for promoting electron transfer between Pd NPs and N-Se-C support,and evoking a strong metal-support interaction?SMSI?.Auspiciously,in comparison with Pd/C,as-obtained Pd/N-Se-C exhibits better catalytic performances,including larger EASA,more negative onset potential,higher current density and longer stability.Additionally,kinetic and thermodynamic studies reveal that it has lower Tafel slope and E_a,leading to a superior charge transfer rate and a lower energy barrier.Overall,this study would shed bright light to exploit an advanced Se codoped-carbon support anchoring metal NPs as high performance electrocatalysts.Part III:Pd Au alloy NPs anchored on P-Se-C support towards glycerol electrooxidationBased on the Se-C support,a novel P and Se co-doped carbon support?P-Se-C?was developed.A series of Pd_n Au/P-Se-C electrocatalyst was prepared by anchoring different proportions of Pd_nAu alloy NPs?Pd:Au=1:1;2:1;3:1?,and further evaluating its glycerol electrooxidation performance.The results show:?I?In comparison with different support,the P-Se-C has the potential superiority,which can make for promoting Pd_nAu/P-Se-C catalytic performance towards glycerol electrooxidation.?II?By testing different ratios of Pd_nAu/P-Se-C electrocatalysts,PdAu/P-Se-C?Pd:Au=1:1?show a larger EASA,higher activity and better stability.These excellent properties are attributed to the optimal ratio of Pd_nAu,as well as the SMSI effect between PdAu alloy NPs and P-Se-C support,leading to a better dispersion of NPs and small nanometer size.It can be predicted that this novel Se co-doped carbon support anchoring NPs has a good prospect as a high performance electrocatalyst in the commercial application of fuel cell.