Study On Iridium Oxide Anodic Catalyst For Oxygen Evolution Reaction

Hydrogen is an ideal fuel with high calorific value and environmental protection.It has good advantages in petrochemical industry and new energy automobile.Unlike solar energy,wind energy and electric energy,hydrogen energy is not affected by geographical and environmental factors and is easy to carry and store.Solid Polymer Electrolyte Water Electrolyzer?SPEWE?is considered as a practical method for hydrogen production because of its high efficiency,high purity and adaptability.However,the cost of electrolysis system has been greatly increased due to the limitation of the cost and reserves of precious metals such as Ir and Ru used as anode catalysts.In order to improve the catalytic activity and stability of IrO₂,this paper is devoted to reducing the amount of Ir and improving the service life of the catalyst?the catalytic activity and stability of 3-DOM IrO₂ and IrO₂ supports were studied.The PMMA microspheres were prepared by the emulsion free polymerization method,and the PMMA template was prepared by gravity sedimentation.The corresponding precursor sol was prepared with ammonia water and IrCl₄,and the 3-DOM IrO₂ catalyst was synthesized.The effects of ammonia addition on the structure of 3-DOM were compared.Meanwhile,Nb-doped SnO₂ was prepared by Na₂SnO₃ and NbCl₅.The effects of Nb-doped amount on the conductivity of SnO₂ and the loading of IrO₂ on the catalytic performance and activity were investigated.The physical properties of 3-DOM IrO₂ and Sn_0.93Nb_0.07O₂/IrO₂ were analyzed by XRD,BET,XPS and SEM.The catalytic activity and stability of 3-DOM IrO₂ and Sn_0.93Nb_0.07O₂/IrO₂ were characterized by electrochemical tests.?1?After heat treatment,it was found that the precursor of ammonia water treatment duplicated the structure of PMMA template at the same time of decomposition.The prepared 3-DOM IrO₂ exhibits honeycomb-like ordered pore structure.The pore size of the macropore is about 155 nm,which is about 35%smaller than the particle size of PMMA microspheres at 220 nm.The pore structure of ammonia-free water treatment is basically disordered,a large number of pore structures are destroyed,only a small number of irregular pore structures exist,far less orderly pore structure of 3-DOM IrO₂.Its specific surface area is also less than 3-DOM IrO₂.At the same time,3-DOM IrO₂ catalyst showed good catalytic performance and stability,which was superior to the same amount of IrO₂ catalyst.?2?The study of Nb-doped SnO₂ supported IrO₂ catalyst showed that the conductivity of SnO₂ reached the optimum 3.53 S/cm when the molar content of Nb-doped SnO₂ reached 7%,and the conductivity did not increase significantly with the increase of Nb content.As Nb doping improves the conductivity of SnO₂,it can improve the conductivity of the catalyst,facilitate the electronic transport of the catalyst,improve the utilization of the active sites of the catalyst and improve the catalytic activity.Sn_0.93Nb_0.07O₂ was used as the carrier to prepare catalysts with different IrO₂loading.It was found that when the IrO₂ loading reached 44 wt%,the catalytic activity of the catalysts was similar to that of pure IrO₂,indicating that the supported catalysts could reduce the use of precious metals.