Preparation Of The Nitride-doped Carbon-based Materials And Their Electrocatalysis Toward Oxygen Reduction Reaction

One of the most important reasons for the high cost of fuel cells is to use expensive platinum catalysts,which greatly hinders the widespread use of fuel cells.It is essential to find alternative catalysts to reduce the cost of fuel cells.In this paper,four nitrogen-doped electrocatalysts were prepared based on the principle of simple and green preparation for oxygen reduction reaction.Materials were analysed by X-ray diffraction?XRD?,Brunauer-Emmett-Teller?BET?,X-ray photoelectron spectroscopy?XPS?,scanning electron microscopy?SEM?,Energy Dispersive Spectrometer?EDS?,High resolution transmission electron microscopy?HRTEM?etc.The properties of the ideal ORR catalysts and related materials were characterized by electrochemical testing:?1?Nitrogen-doped graphene oxide?N-PEGO?.N-PEGO was obtained by fast and eff ective dielectricbarrier discharge?DBD?plasma technology.The plasma treatment could provide a burst open and high-energy electron/ion collision mechanism for doping and exfoliation.Ammonium carbonate was previously inserted into the interlayer of GO powder,and the rapid release of the NH3 and CO2 gases during DBD plasma treatment could exfoliate the GO powder into few-layer PEGO?<4 layers?.Moreover,the plasma treatment also introduced the nitrogen dopant?5.26 at.%?,which is proven to be an efficientstrategy to enhance the performance of oxygen reduction reaction?ORR?electrocatalysts.The resulting N-PEGO showed a high onset potential comparable to that of commercial Pt/C,i.e.,0.89 V vs.reversiblehydrogen electrode?RHE?and good electrocatalysis stability towards the ORR.This fast and eff ective one-step doping and exfoliation strategy demonstrated a new industrial-scale N-doped grapheme fabrication technique.?2?Nitrogen-doped pomelo peel-derived active carbon.The preparation method is same as?1?.Nitrogen doping?2.7 at.%?result in a obvious improvement in the electrocatalytic activity of pomelo peel-derived activated carbon?PPAC?.Moreover,the increase in the specific surface area(1789.17 m² g^-1)led to the generation of more catalytically active sites.Furthermore,the resulting nitrogen-doped pomelo peel-derived active carbon?N-PPAC?not only showed a high onset potential?0.90V vs.RHE?approach to commercial Pt/C,but also exhibited superior electrocatalytic stability and methanol resistance.Low temperature plasma can also be used for nitrogen doping in general carbon materials.?3?Nitrogen,sulfur co-doped biomass based porous carbon.Biomass-derived porous carbon was prepared from agricultural waste and adsorbed azo dyes from dye wastewater as nitrogen and sulfur resource.Banana peel-derived carbon material was adsorbent to absorb dye.With carbonization of carbon and dye,the specific surface area of the material is higher.Besides,content of nitrogen and sulfur were also increased.The N content nitrogen is 2.84 at.%.Heteroatom-doped porous carbon was successfully synthesized from the BPPC absorbed MO at high temperature and used for oxygen reduction.The nitrogen,sulfur co-doped banana peel-derived porous carbon?BPPC-MO50?displays the highest ORR onset potential among all carbon-based electrocatalysts,i.e.,0.93 V vs.reversible hydrogen electrode?RHE?.BPPC-MO50 has excellent stability.These results may contribute to the sustainable development of dye wastewater treatment by transforming saturated PC into an effective material and has potential applications in fuel cells.?4?Nitrogen and iron co-doped biomass-derived carbon.The catalyst comprised of Fe₂N nanoparticles?NPs?in situ decorated over an N-doped porous carbon derived from pomelo peel?i.e.,Fe₂N/N-PPC?.The decorated Fe₂N NPs provided large quantities of Fe-N-C bonding catalytic sites.The as-obtained Fe₂N/N-PPC showed superior onset and half-wave potentials?0.966 and 0.891 V,respectively?in alkaline media?0.1 M KOH?compared to commercial Pt/C through a direct four-electron reaction pathway.Fe₂N/N-PPC also showed better stability and methanol tolerance than commercial Pt/C.The outstanding ORR performance of Fe₂N/N-PPC was attributed to its high specific surface area(1103.90 m²·g^-1)and the synergistic effects of Fe₂N NPs.The utilization of agricultural wastes as a precursor makes Fe₂N/N-PPC an ideal non-precious metal catalyst for ORR applications.