Preparation Of Multi-component Catalysts Such As Palladium And Molybdenum And Their Anodic Oxidation Performance Of Methanol

Energy is the foundation of human development and the driving force of social progress.With the continuous development of economy and society,fossil fuels are depleted day by day,and the problem of environmental pollution is becoming more and more serious.It is urgent and imperative to develop and utilize new clean energy.Methanol is considered"liquid sunlight",a natural solar transporter.Direct methanol fuel cell(DMFC)is an energy conversion device with simple structure,easy operation and instant refilling.The principle is very simple,that is,methanol is decomposed into water and carbon dioxide through a catalytic reaction,and chemical energy is converted into electrical energy.Moreover,methanol fuel has high energy density,a wide range of sources,safe storage,and convenient transportation,which can be used even in isolated environments or remote areas without power grids.Considered one of the most promising power alternatives for portable devices,military applications and cars in the small power range.The anodic methanol oxidation reaction(MOR)of DMFC has slow kinetics and requires the use of anode catalysts with excellent performance.Pt has the highest catalytic activity for methanol oxidation,but Pt is expensive and its anti-poisoning performance needs to be improved.Based on this,this paper starts from two aspects.On the one hand,it focuses on the development of Pd-based catalysts that can replace Pt.On the other hand,it focuses on the construction of the core-shell structure of Pt-based catalysts,reducing the amount of Pt used and improving its anti-poisoning performance.The following is the specific research content:(1)In Chapter 3,a Pd₉Mo/GO catalyst was successfully prepared by using graphene oxide(GO)as a support material.Its mass activity for methanol catalytic oxidation were 2 times,1.7 times and 3.2 times higher than that of Pd₇Mo/GO,Pd₁₂Mo/GO and commercial Pd/C,respectively,and the stability and anti-toxicity were improved.Therefore,the introduction of the support GO and the oxophilic element Mo can indeed improve the electrocatalytic performance of Pd for MOR.(2)In Chapter 4,a PdCTABMo ion-associate supporting Pd composite catalyst Pd/PdCTABMo was successfully prepared.The ion associate is a layered structure with good electrical conductivity,defects such as kinks,steps,strain pressure,etc.,which help to improve the catalytic performance.In addition,the metal Pd nanoparticles supported by the ion-associate is embedded in the pores of the layered material,which can not only avoid the aggregation and electrochemical dissolution of Pd nanoparticles,but also improve the atomic utilization of Pd and increase the catalytic active sites,thereby improving the catalytic activity and stability.Electrochemical tests show that among the three Pd/PdCTABMo catalysts,Pd_1.8Mo exhibits excellent electrocatalytic performance.(3)In Chapter 5,three kinds of hollow core-shell composites(the core is Pd Ag alloy and the outer shell is Ag Pt alloy)were successfully prepared by the self-template method of intermetallic displacement reaction through the difference of redox potential.The core-shell structure has multi-layer electrochemically active surface areas in inside the core,outside the shell and between the core-shell contacts,which can fully utilize the synergy between metals and structural effects to enhance the electrocatalytic activity,stability and anti-poisoning ability.