The Electrochemical Performance And Application Of Nitrogen-doped Carbon Supporting Metal Nanoparticles

The development of renewable energy is already one of the most promising solutions tomeet the global energy crisis.Due tothe limitations of the intermittent production of renewable energy sources and unstable output,a lot of research had focused on the direction of continuous production and safe storage.As one of the emerging energy sources in the 21st century,hydrogen energy has been widely concerned and researched due toits high energy density,environmental friendly,and zer Ocarbon emission.It is als Oconsidered tobe the most potential secondary energy source.As a downstream product driven by hydrogen energy,fuel cells have great potential toreplace traditional cars motivated by combustion engine in the future market,and have advantages over lithium batteries in terms of long distance and power energy density,s Othey can complement lithium batteries for long-distance transportation in the future market.In addition,metal-air batteries are regarded as an ideal substitute for lithium batteries as an efficient,pollution-free and high energy density.However,the cost and short lifespan of the above-mentioned emerging energy and catalysts in energy conversion technologies have seriously affected long-term market applications.Therefore,the development of cheap and efficient catalysts is one of the key themes toadvance technological progress.We used nitrogen-doped carbon as the carbon support acted as the novol point toexplore the effect of the support toward the activity of the catalyst.For hydrogen evolution reaction(HER),oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),the currently most widely used commercial catalysts are all noble metal catalysts,such as commercial Pt/C,IrO₂ and RuO₂.Due tothe cost limitation of precious metals,this article is to reduce the amount of precious metals and develop new non-precious metal catalysts with ensuring the electrochemical performance.In addition,carbon-based materials are widely used in the field of catalysis due totheir low cost and excellent electrical conductivity.However,carbon materials are rarely studied as carriers,s Onitrogen-doped carbon is used as a carrier toimprove the performance of the catalyst.The following tw Otasks have been carried out:(1)Using SiO₂ as a hard template todesign the pore structure of the material and the method of atom transfer radical polymerization was used tograft on the surface of the template,ethylene glycol was used toreduce H₂Pt Cl₆ and the Pt particles were uniformly dispersed on mesoporous carbon surface.The final synthesized catalyst was physically characterized,and small-sized Pt nanoparticles were uniformly distributed on the surface of the carbon material substrate.After EDS characterization,it was observed that Pt was uniformly distributed around N atoms.There are certain restrictions on growth.More importantly,compared with commercial catalysts,synthetic catalysts have higher specific surface area,catalytic activity,and excellent stability.This method provides a new idea and strategy for modified support materials.(2)Using glucose and dicyandiamide as precursors to prepare carbon materials can provide abundant lone pair electrons and carbon templates.Among them,carbonized mixed samples of dicyandiamide at 550?can form graphite phase carbon nitride(g-C₃N₄),which helps the metal ions tobe successfully incorporated intothe carbon metal skeleton at high temperature;glucose will be at 550?.A carbon template is formed,and a layered structure is formed during the final carbonization process toprovide the template.In order tomeet the requirements of bifunctional electrochemical performance,we synthesized a bi-metal alloy and a metal-doped carbon material toachieve excellent bi-functional catalysis.Through electrochemical tests,we can know that the ORR activity of bimetals is superior tosingle metal catalysts and commercial platinum carbons.This can be explained by the synergy of bimetals.In addition,some metals exist in the form of alloys,and the alloys have excellent catalytic activity for the oxygen precipitation reaction.Compared with the electrochemical performance of commercial catalyst IrO₂,the synthesized catalysts have lower overpotential and excellent stability.This two-step pyrolysis method provides an effective idea for large-scale production of dual-functional catalysts and a strategy for achieving dual-functional catalysis toone catalyst.