Synthesis And Electrochemical Properties Of Transition Metal Compounds

The dissertation focuses on the preparation of transition-metal compounds and hybrid nanomaterials,and their applications in supercapacitors and fuel cells.Firstly,K-birnessite nanoflakes with large specific capacitance are prepared in high yield by heating potassium permanganate and potassium oxalate via a hydrothermal method.The morphology and chemical composition of the nanoflake are examined by a series of characterizations,and the electrochemical behaviors as electrode material for supercapacitor are studied.Then phosphotungstic acid-graphene composite material with well-performed electrochemical capacitive behavior is obtained by simply mixing the two components.Moreover,phosphotungstic acid/palladium/graphene hybrid nanomaterial is also synthesized by a onestep photoreduction method.Electrochemical results show the hybrid nanomaterial exhibit enhanced mass catalytic activity compared with commercial Pd/C catalyst,indicating the hybrid may be suitable as anode electrocatalyst for direct alcohol fuel cell.All results show that the prepared materials display excellent electrochemical properties and possess great potential in supercapacitors and fuel cells.