Study On Preparation Of Non-precious Metal ORR Catalysts By Biomass And Template Method

The platinum-based fuel cell catalyst is expensive,short life,poor anti-toxicity and other limitations for large-scale commercial applications,so the research on the substitution of the platinum-based precious catalyst is still one of the main research topics.High protein biomass contains nitrogen and rich metal elements,the transition metal and nitrogen atoms formed by the macrocyclic complex is the main active site of the fuel cell catalyst,is a class of potentially efficient catalyst raw materials.In this paper,the N-C@CNT-Fe,N-BC@G and FS350Z-X catalysts were synthesized by using stoichiometric biomass,mushroom,fish scale and hemoglobin as carbon sourcewith the,using different stages of heat treatment and adding different activators.And the Fe-N/C-PANI catalyst was prepared by template method.The mechanism of oxygen reduction catalyzed by non-noble metal catalysts prepared by template method is as follows:（1）The N-C@CNT-Fe catalyst was synthesized by the addition of carbon nanotubes（CNT）and FeCl₃.6H₂O using a two-step heat treatment method using hemoglobin as carbon source,and its properties were characterized.The results showed that the initial and half-wave potentials were 45 mV and 54 mV higher than those of the commercial Pt/C catalyst,respectively.The oxygen reduction process showed 4 electron transport process,and the catalysts showed good stability both in acid and alkaline conditions,which could be an ideal substitution of the Pt/C catalyst.（2）The N-BC@G catalyst was prepared by mixing the precursor and melamine in a two-step heat treatment method using the chicken leg mushroom as the carbon source.The results were as follows:Melanization forms a G-C₃N₄ structure during carbonation at 600℃,which can be used as a self-sacrificial template to produce nitrogen-doped graphene-like（GNS）.The heat treatment at 900℃results show that N-BC@G-900catalyst has good oxygen reduction catalytic activity with a half-wave potential of0.83V（vs.RHE）.The catalysts present good stability alkaline environment and Alcohol-resistant methanol property.N-BC@G-900 catalyst has the characteristics of low cost and high performance,easy to synthesize,and is suitable for the practical application of high performance alkaline fuel cell.The catalyst can effectively improve the electrocatalytic activity of the catalyst in the high percentage of graphite nitrogen atom;（3）The FS350Z-X catalyst was prepared by reacting the protein-rich fish scale bio-waste with ZnCl₂ and acid treatment,respectively.The results show that the catalyst has good redox electrocatalytic activity and stability compared with commercial Pt/C catalyst in alkaline and acidic solution The starting potential of oxygen reduction is 20mV higher than that of Pt/C catalyst,presenting good activity and stability;（4）Montmorillonite（MMT）was used as the solid-phase plane template to synthesize the Fe-N/C type catalyst,and the aniline nanometer polymer was used as the nitrogen and carbon sourceto synthesize the Fe-N/C-PANI catalyst.The results show that the catalyst has high selectivity to the 4-electron reaction pathway in alkaline solution,and the starting potential is up to 0.99 V.The half-wave potential is 10 mV lower than that of the standard Pt/C catalyst,and the catalyst has good oxygen reduction activity and stability.This study clearly reveals the active sites and possible reaction mechanism of carbon based ORR catalysts,which provides the basis for the development of more excellent carbon based catalysts,and it is one of great significance for further building a new energy battery system.