Preparation Of Cobalt-based Catalyst And Study On Its Electrocatalytic Oxidation Performance Of Methanol

Fuel cell is one of the most important parts of clean energy equipment in the 21st century.Among them,direct methanol fuel cell（DMFC）has become a research hotspot due to its low reaction temperature,high efficiency and easy preservation.In the methanol oxidation reaction（MOR）,the main factor affecting the reaction rate is the performance of the catalyst.Therefore,it is very important to develop the catalyst with low cost and high activity.In this paper,the new high conductivity polyaniline（polyaniline polyvinyl alcohol conductive hydrogel,PPH）was used as the catalyst carrier.The metal active components were loaded into PPH through different preparation methods to prepare M-N/C materials.And they were tested by XRD,thermogravimetry,XPS,SEM,TEM,etc.The specific contents and results are as follows:1.Under hydrothermal conditions and optimized experimental conditions,the optimal material Co₁/CoO/Co₂-N-C-500 catalyst was prepared.The structural characterization results show that the catalyst has a three-dimensional porous structure with an average pore size distribution between 9-12 nm,which is characteristic of a mesoporous material.Electrochemical test results show that the current density of Co₁/CoO/Co₂-N-C-500 catalyst in alkaline methanol electrolyte（1.0 M KOH+1.0 M methanol）can reach 91.68 m A cm^-2 at0.6V vs SCE,and the current density after 1000 CV cycles retention 91.1%,which shows good stability.The main reason for the excellent mor activity and stability of the catalyst is that the three-dimensional porous structure not only provides a channel for methanol oxidation,but also protects cobalt and cobalt oxide nanocrystals.2.The Co/N-C-1-500 catalyst with sandwich structure was synthesized by impregnation method.The average pore size distribution is between 1.85 nm and 21.6 nm,which belongs to macroporous material.Electrochemical test results show that the current density of Co/N-C-1-500 catalyst in alkaline methanol electrolyte（1.0 M KOH+1.0 M methanol）can reach 119.08 m A cm^-2 at 0.6V vs SCE.The current density after 1000 CV cycles,the electrode retention 67.9%(1000^th cycle)and 87.9%(1001^th cycle,with fresh electrolyte solutions)of the current density of the 1^st cycle at 1.0 V.In the anti-CO poisoning experiment,the current density retention rate of the Co/N-C-1-500 catalyst in the CO saturated solution was 93.5%.The catalyst prepared by this method has larger pore size and higher conductivity.3.Co/N,O-C（FT）@500 catalyst was synthesized by electrodeposition on the surface of PPH（NF）electrode.Electrochemical test results show that the current density of Co/N,O-C（FT）@500 catalyst in alkaline methanol electrolyte can reach 352.4 m A cm^-2 at0.6V vs SCE,and the current density after 1500 CV cycles retention 86.7%.In the anti-CO poisoning experiment,the current density retention rate of the Co/N,O-C（FT）@500 catalyst in the CO saturated solution was 93%.This method not only increases the load of cobalt,but also makes the catalyst into a whole.As a working electrode,it has high conductivity（1.538×10⁴ S/cm）and electrocatalytic performance.