Partial Research On The Regulation Of Electrochemical Oxygen Evolution Performance Of Ir And Ru Multi-component Oxides

Nowadays,the pollution situation in our country is serious,especially about air and water pollution.We can solve the problem of air pollution mainly through the development and utilization of emerging energy sources such as solar energy and wind energy;clean energy hydrogen has potential application value;the electrochemistry can efficiently convert the new energy into the form of hydrogen,which is conducive to transportation and storage.To solve the pollution of water body,the strong oxidation ability of electrochemistry can be used to oxidize and decompose organic pollutants.It can be concluded that electrochemistry can play a huge role in the field of environmental protection.However,the anode oxygen evolution reaction in electrochemistry has extremely high reaction barriers.In-depth and systematic research on this issue can help electrochemistry play a broader and more important role in the field of environmental protection.This paper discusses the basic problems in electrochemical reactions,and conducts an in-depth study on the regulation of the oxygen evolution reaction performance of noble metal-based catalysts in acidic environments.The main work is carried out around the following aspects:(i)The research about effect of perovskite Ir-based compound Ca2IrO4 as a catalyst on OER activity:materials of Ir-containing perovskite Ca2IrO4 and CaIrO3 were prepared by hydrothermal method and sol-gel method,respectively,and the effect of crystal phase composition of the material on OER activity was studied.Through characterization,we found that different perovskites have significant differences in catalytic activity.In an acidic environment,Ca2IrO4 shows a higher catalytic activity of 7 mA/cm2 compared with IrO2,while CaIrO3 does not.In terms of acid corrosion resistance,Ca2IrO4 shows no significant decline compared with IrO2.XPS and XAS data indicate that the valence state of the Ir element in Ca2IrO4 and CaIrO3 is higher,and the twisted octahedral symmetry leads to a strong interaction between the Ir-5d state and the oxygen intermediate.This study emphasizes the role of the coordination ability of Ir and O bonds on the catalytic ability of water electrolysis,and proposes a new perovskite OER catalyst that is different from traditional rutile phase catalysts,which provides new ideas for the subsequent design of more efficient catalysts(ii)The research about effect of rutile phase Ni and Fe codoped RuO2 as catalyst on OER activity:the traditional OER catalyst RuO2 is doped with bimetal to study its effect on catalytic performance.Studies have shown that for the rutile OER catalyst RuO2 with two doping element ratios,co-doping can be considered as a feasible method.Among them,Ru0.9(NiCol.5)0.1O?(32 mV/dec)showed higher catalytic activity compared with pure RuO2(64 mV/dec),while maintaining stability.XRD,SEM and TEM test results show that when RuO2 is co-doped with Ni and Co metal dopants,its lattice maintains the rutile phase.XPS data indicate that the increase in oxygen vacancies and the higher valence of Ru sites lead to modification of the host metal.As the doping element molar ratio(Co/Ni)changed from 1 to 1.5,this change significantly enhanced OER activity.In short,our proposed co-doping method with different doping ratios can provide more ideas for studying the influencing factors of OER catalyst to further reduce the precious metal content.(iii)The research about effect of Mn and Fe double transition metal doped RuO2 catalyst on OER performance:the catalytic efficiency of the catalyst is further improved by reducing the content of noble metal in traditional RuO2 and doping with transition metals.Studies have confirmed that manganese and iron can be used as two transition metal double-doped elements in rutile-type OER catalyst RuO2 at a molar ratio of 1:1 doping elements.Compared with pure RuO2,Ru0.9(MnFe)0.1O? shows more enhanced catalytic activity by 24 mV/dec while maintaining high stability.According to the test results of XRD,SEM and TEM,when codoped with Mn and Fe in the ratio of 1:1,RuO2 will maintain the rutile lattice structure.XPS test results show that the higher oxidation state of Mn sites and the increase of oxygen vacancies will lead to the modification of the host cationic metal Ru.In this regard,co-doping has a significant effect on the enhancement of OER activity of Mn/Fe bimetallic doped RuO2 with a molar ratio of 1.We believe that the bimetallic doping method with a molar ratio of 1:1 will help to study the influencing factors in water electrolysis OER to further reduce the precious metal content.Bimetallic doping has greater flexibility than single metal doping,and can even break through the limitation of single metal doping,which more effectively enhances the OER catalytic activity of Ru-based oxides.