Preparation And Eletracatalytic Application Of Heteroatom Doping Porous Carbon Materials

Due to the deepening of the energy crisis and the increasing environmental pollution of fossil fuels,the development of new energy conversion and storage devices has become a research hotspot.Environmental-Friendly and renewable energy technologies,such as fuel cells and water splitting,are promising to solve current energy and environmental problems.Oxygen reduction reaction?ORR?and oxygen evolution reaction?OER?are critical to the advancement of renewable energy conversion and storage techniques.However,whether it is an oxygen reduction reaction or an oxygen evolution reaction,a catalyst is required to increase the reaction rate.At present,the catalysts commonly used in ORR are Pt-based catalysts.The catalysts commonly used in OER are RuO₂ and IrO₂.However,due to the shortcomings of these precious metals,such as low storage,high price,and poor stability,commercial applications are limited.Therefore,it is of great interest to explore non-precious metal catalysts that are both inexpensive and highly catalytical active.Here,three hetero atom-doped porous carbon materials were prepared as excellent catalysts.The preparation method is as follows:?1?A novel composite material?FeNi₃@NC-1000?is prepared by hydrothermal reaction and high temperature calcination as an electrocatalyst for efficient oxygen reduction and oxygen evolution in alkaline medium..In a 0.1M KOH alkaline medium,FeNi₃@NC-1000 has a positive oxygen reduction onset potential of 0.90 V,a half-wave potential of 0.78 V,and a limiting current clandestine of 6.3 mA cm^-2.In a 1M KOH alkaline medium,FeNi₃@NC-1000 has a smaller overpotential than RuO₂ at 10 mA cm^-2.Stability test and anti-methanol test also show that FeNi₃@NC-1000 has good stability and methanol tolerance;?2?A typical ZIF-67 is prepared by a common stirring and aging method,and an appropriate amount of thiourea is added during the synthesis to synthesize a sulfur-nitrogen double-doped composite?ZIF-S-800?as an efficient oxygen reduction catalyst in an alkaline medium.The catalyst not only has excellent ORR catalytic activity in alkaline medium,its initial potential is 0.92V,half-wave potential is 0.84 V,limiting current density is 4.82 mA cm^-2,but also has good durability and methanol resistance;?3?Co-series is synthesized by a simple solvothermal method using ethanol as a solvent.Under the ice water bath condition of 0-8°C,the ferric chloride was used as an oxidant,hydrochloric acid was added to form an acidic environment,and the Co nanowires and the pyrrole were polymerized together.Finally,high temperature pyrolysis forms the final product nitrogen-doped porous carbon-supported CoFe nanoparticles?CoFe@NC-800?catalyst.CoFe@NC-800 has good ORR performance under both alkaline and acidic conditions.The ORR onset potential is 0.96 V in alkaline solution and the ORR half-wave potentiall is 0.8 V in acidic solution.The composition and structure of the material were first analyzed by X-ray diffraction?XRD?and Raman spectroscopy?RS?.The morphology and composition of the catalysts were characterized by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,X-ray photoelectron spectroscopy?XPS?,and nitrogen adsorption desorption test?BET?.Finally,the electrochemical tests of the catalysts were carried out by electrochemical tests such as CV,LSV,RRDE and i-t.The obtained results demonstrate that all of the as-prepared catalysts have good catalytic activity,excellent stability and durability.