| Electrocatalytic reaction is regarded as one of the most critical research topics in the field of new energy,also as the core reaction of hydrogen production,fuel cells,metal air and electrolysis of water.Current commercial electrocatalysts mainly rely on precious metal and their alloy materials,the high cost of precious metal limits the practical application and development of electrocatalysts.Therefore,the development of efficient and economical non-precious metal catalysts is a key step of advanced electrocatalyst research.Carbon materials have many advantages such as high conductivity,quantity microstructure and low cost,they can exhibit enhanced and modulatable electrocatalytic properties through element doping and structure recombination.In this dissertation,polyaniline was pyrolyzed to porous carbon as the matrix material.The effects on the electrocatalytic properties of nitrogen,phosphorus,and iron phosphides doping were systematically investigated,the multi-functionality to water electrolysis was investigated including oxygen reduction,oxygen evolution,and hydrogen evolution,the relationship between the shape and size of the material,microstructure,surface chemical state and the electrocatalytic properties was also researched,and explored the mechanism of these reaction,we obtained a dual function or three functional electrochemical catalysts.The main results of this article are briefly summarized as follows:?1?Firstly,the three-dimensional network polyaniline was solution polymerized by the soft template method.On the basis of optimization of the polyaniline process parameters,nitrogen and phosphorus doped porous carbon was obtained by controlling pyrolysis temperature.By adjusting the temperature parameters,the nitrogen-phosphorus-doped porous carbon material obtained by pyrolysis at 1000?has the properties both of oxygen reduction and oxygen evolution.The onset potential of oxygen reduction was 830 mV,and the limiting current density was 4.4 mA cm-2.When the oxygen evolution reaction current density was 10 mA cm-2,the onset potential was 1.80 V.?2?In this work,polyaniline was synthesized by the sol-gel method.By adjusting the proportion of the precursor,the synthesized polyaniline three-dimensional network has the advantages of controllable morphology and stable structure.The pyrolysis temperature was controlled at 1000?,compared with the solution method,the current density of the nitrogen-phosphorus double doped porous carbon material obtained by the sol-gel method was increased to 6.3 mA cm-2,and the onset potential was 820 mV;When the reaction current density is 10 mA cm-2,the onset potential is1.82 V.?3?Iron-doped polyaniline was synthesized by sol-gel method by the adjunction of iron-containing precursors,and the concentration of iron-containing precursors was adjusted at 1000?,when the mole ratio of ferric chloride to aniline was 0.1.The synthesized porous carbon material has optimized electrocatalytic properties.The oxygen reduction limit current density reached to 6.3 mA cm-2,and the onset potential was shifted to 920 mV.Both indicators exceeded the commercial Pt/C catalyst;the onset potential is 1.82 V at a current density of 10 mA cm-2for the oxygen evolution reaction.?4?The morphology of Fe-doped polyaniline synthesized by the solution polymerization method is relatively coarse.By optimizing the temperature parameters,the iron-phosphorus/phosphorus ferrous biphase doped porous carbon material was obtained at 850?.The obtained structure possesses three functional electrocatalytic activities of oxygen reduction,oxygen evolution and hydrogen evolution:the limiting current density of oxygen reduction is 6.0 mA cm-2,the onset potential is at 910 mV,and it is close to that of Pt/C;When the current density is 10 mA cm-2,the onset potential is 1.81 V;when the hydrogen evolution reaction current density is 10 mA cm-2,the onset potential is 251 mV.?5?The nickel cobalt oxide/carbon composite structure was synthesized by hydrothermal method,the temperature and the phase structure and electrocatalytic properties of the single component or composite structure were compared and analyzed in detail.The spinel structure of nickel-cobalt oxide obtained by annealing at350?has optimized electrocatalytic properties:the limiting current density is 2.9mA cm-2,the oxygen reduction onset potential is at 895 mV.and the current density is10 mA cm-2,the oxygen evolution onset potential can be negatively shifted to 1.62 V. |
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