The Preparation And Application Of Transition Metal-carbon Composite Materials Based Electrocatalysts

Carbon nanomaterials?such as graphene,carbon nanotubes,ordered mesoporous carbon,carbon nitride,and carbon fiber?have recently received much attention owing to the possession of unique properties,which are generally dissimilar with those of their original bulk materials.Graphene-based nanomaterials are some of the carbon-based nanomaterials that have received much consideration due to their spectacular properties.Graphene is single layer graphitic close-packed conjugated hexagonal lattices with outstanding electronic,thermal,optical,thermal and mechanical properties.The development of GR offers an admirable substitute to electrode materials,as encouraging materials for an electrode with extraordinary performance in the field of energy storage and harvesting devices due to the large specific surface area effective electrical conductivity,abundant interlayer structure,and plentiful functional groups are involved.In order to ease GR appropriateness for various applications,amendment into a porous skeleton and heteroatom doping are some of the most acknowledged strategies.Nitrogen-doped GR?NGR?is also an eminent material.It displays very good catalytic activity,excellent reliability,and environment friendliness.The nitrogen doped carbon?NC?materials hold many captivating properties and were being extensively used for many applications.The doping of heteroatoms can alter the electronic properties of the GR nanomaterials and create extra functional groups on the GR surface,and this generally boosts the electrochemical performances.By keep studying the previous researches.In chapter two,an enzymeless sensor for H₂O₂ detection was assembled by supporting CoFe nanoparticles on the NGR).In this fabrication,the graphene oxide?GO?is first used as a substrate for the growth of CoFe layered double hydroxides?CoFe LDHs?by hydrothermal reaction.Then,the pyrolysis of CoFe LDHs/GO under ammonia(NH₃)produces CoFe/NGR.By anchoring CoFe nanoparticles on NGR,the electrocatalytic activity of CoFe is melodramatically enhanced due to the high electrical conductivity of NGR.Subsequently,the mixture of CoFe and NGR permits the non-enzymatic detection of H₂O₂.In comparison to the unsupported CoFe nanoparticles,the CoFe/NGR shows high electrocatalytic activity towards H₂O₂,allowing a high sensitivity of 30.78?A mM^-1 and low detection limit of 0.28?M towards the detection of H₂O₂.Particularly,the promising feature of economical and superb analytical activity of CoFe/NGR proposes its great ability in the fabrication of biosensor and an electrochemical sensor.Moreover,in chapter three,C₃N₄ is doped with cobalt species and supported on ordered mesoporous carbon?Co-C₃N₄/OMC?for ORR.The structural characterization proves Co-N bond in Co-C₃N₄.The ORR activity of Co-C₃N₄/OMC is might be improved by rich approachable Co-N_x active sites and rapid transfer in the pores of Co-C₃N₄/OMC.The electrocatalytic properties reveal that reduction of oxygen is in a four-electron pathway.Additionally,Co-C₃N₄/OMC unveils equivalent ORR performance?maximum methanol tolerance ability and improved durability?in contrast to Pt/C and promising material for designing of favorable non-precious cathode catalyst in fuel cells.The chemical doping approach in this work provides insights to advance another related catalyst in fuel cells.