Preparation And Electrochemical Application Of Porous Carbon Derived From Human-hair

The depletion of fossil fuels and severe ecological environment greatly stimulates the development of clean and sustainable energy devices.The rechargeable metal—air batteries with high energy density are one of the promising technologies for future electric vehicles and powering portable consumer devices.The oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are two fundamental reactions in rechargeable metal-air batteries.The two reactions correspond to the discharge and charge processes separately,which determines the performance of rechargeable metal air batteries.So,developing the highly efficient bi-functional electrocatalyst is a key for wide applications of rechargeable metal air batteries.Polymer electrolyte membrane fuel cells are efficiency energy convert devices which can transfer chemical energy into electricity without burning.In fact,the ORR is also one of the fundamental reactions in fuel cells happened at cathode.The fuel cells have various advantages,such as high capacity,high energy density and environmental friendly.The fuel cells are also considered to be the possible replacement for fossil fuel.However,the ORR is six or more orders slower than the reaction at the anode,which means that ORR limits the performance of fuel cells.Until now,the platinum(Pt)has been regarded as the most efficient ORR catalyst.Nevertheless,the wide application of fuel cells is restricted by the Pt catalyst due to its high cost,low stability and poisoning of methanol.Porous carbon has huge surface area and high stability,which are promising candidate for electrocatalyst.Biomass is organic derived from living organisms,which usually has abundant reserves and contains rich organic content.These premises make that biomass is a possible candidate for electrocatalyst.Actually,there are already many researches focused on using biomass as precursor to prepare the electrocatalyst.Human-hair is a biomass organic waste,containing abundance nitrogen and sulfur.We prepared N-doped and Fe-N-doped porous carbon derived from human hair.The process contains pre-carbonization,activation and pyrolyzation.Through doped second carbon source and nitrogen source,we enhance the materials nitrogen content and change the pore size distribution.The metal-free material H-Carbon-G-U showed excellent ORR activity and better stability than commercial 20%Pt/C.Through doped transition metal into the material,we prepared the material Fe/Fe2C@ H-Carbon-GU,which is graphene encapsulated Fe/Fe2C nanoparticles and hierarchical porous structure.The material showed bigger oneset potential and half-wave potential.The electric transfer number is near 4.Besides this,the material showed good OER activity.So,the Fe/Fe2C@H-Carbon-GU is an excellent material for bi-functional electrocatalyst.