| The fourth scientific and technological revolution is budding,and the demand for energy is growing with each passing day in today’s extremely rich material conditions.The reserves and efficiency of traditional fossil energy such as coal and oil have gradually falled behind the needs of the Times.Therefore,while developing new energy such as controlled nuclear fusion,combustible ice and geothermal,we should also develop more efficient utilization methods for existing energy.Fuel cell has attracted wide attention because of its high energy conversion efficiency,high reliability,wide range of fuel types and environmental friendliness.It provides a solution for the serious energy and environment problems which mankind faced at present.For example,hydrogen energy is a kind of carbon-free energy with low atomic mass and zero emissions.It has higher mass energy than petroleum and can be used as fuel for the electrode,which makes it suitable for replacing fossil fuels as a kind of efficient energy to meet global energy demand.As the most extensive source of hydrogen production,water splitting technology is limited by the slow kinetics of hydrogen precipitation（HER）and oxygen precipitation（OER）reactions,which hinders the large-scale application of hydrogen fuel cells.At the same time,direct alcohol fuel cells have received extensive concern due to its advantages of excellent energy density,high energy transformation efficiency,easy storage and safe operation.However,in the actual process,electrode reactions such as oxygen reduction and ethanol（ethylene glycol）oxidation（ORR,EOR（EGOR））have slow kinetics and high reaction energy barrier.So that its large-scale application is under restrictions.Therefore,accelerating electrode reaction kinetics and reducing electrode overpotential are urgent problems to be solved in this field for fuel cells.Pt and Pd based precious metals show excellent electrocatalytic performance.However,the high cost and scarcity of precious metal catalysts hindered their large-scale application in production.Therefore,low load noble metal and non-noble metal catalysts have become the focus of research.Amorphous materials have short-range ordered properties,low bond energy,a large number of dangling bonds and surface defects,which provide more active sites,optimize the adsorption and desorption of reactants and intermediates,so that the catalytic activity can be improved.Remodeling crystalline/amorphous metal oxide interface through the interface engineering can increase the number of the activity sites while effectively retaining the unique advantages of crystalline and amorphous.The interaction between them can make the surface active center refactoring,resulting in a strong interface coupling effect which can enhance the interfacial charge transfer dynamics and create new catalytic active site and optimize reaction pathways.Thus,they showed higher electrocatalytic activity.In this paper,three kinds of interface structures are constructed based on amorphous metal oxides and their electrocatalytic properties are studied.The specific work is as follows:（1）Study on EGOR electrocatalytic performances of heterostructures PdCo/CoOxPdCo/CoOx catalysts with different material ratios were prepared by solvothermal method and in-situ etching method.The unique isotropic structure of amorphous Co/CoOxsupports enables the catalyst to have larger area volume ratio and more oxygen vacancies.The heterostructure formed between Pd and amorphous supporter changes the electronic structure of Pd,accelerates the desorption of intermediates（especially CO）from the catalyst surface,and improves the long-term stability of the catalyst.Meanwhile,the synergistic effect of Pd and CO provides more active sites.The catalyst showed excellent EGOR catalytic performance and stability,with mass activity of 3933 m A mg PPd-1 under alkaline condition,which is much higher than commercial Pt/C.（2）Study on HER electrocatalytic performance of Pt Ni-CeOx/C amorphous NPsPt Ni-CeOx/C amorphous NPs catalysts with different loading were prepared by co-reduction method at room temperature.The introduction of CeOx effectively transformed the catalysts from crystalline state to amorphous state,and provided excellent electronic structure flexibility and enhanced catalytic activity of the catalysts.The addition of Ni can improve the electronic structure of Pt through the electron transfer of Pt Ni.Pt and Ce can change the hydrogen adsorption energy,thus reducing HER energy barrier and accelerating reaction kinetics.XC-72 enhanced the conductivity,reduced the agglomeration of NPs,and exposed more active sites of the samples.For the above reasons,the material showed excellent HER catalytic performance and stability and the amount of precious metal Pt was greatly reduced,thus the cost of catalyst was reduced.（3）Study on the performances of Co3O4-SMO catalysts with crystalline/amorphous heterostructuresCo3O4-SMO amorphous heterostructure nanomaterials with compact interface were synthesized by one-step hydrothermal method.Crystalline/amorphous heterostructure and interface charge are the main reasons for the improving catalytic performance.Due to the difference of work function,electron transfer from Co3O4 to SMO provides more active sites and oxygen vacancies on the interface,which is conducive to faster charge transfer,optimizing adsorption energy of O species and improving electrical conductivity.Compared with Co3O4 and SMO,Co3O4-SMO nanoparticles have higher half-wave potentials and higher ORR catalytic activity.In terms of stability,Co3O4-SMO nanomaterials have higher durability and methanol tolerance than commercial Pt/C. |
