Study On Interface Catalytic Mechanism And High Temperature Electrolytic Properties Of Ceramic Electrode Metal Oxide

Solid oxide electrolyzer cells（SOEC）are high-efficiency energy conversion devices that convert water and carbon dioxide into hydrogen and carbon monoxide.Through solid oxide electrolysis cells,it can reduce greenhouse gas carbon dioxide emissions,achieve large-scale energy storage and conversion,and promote the integration of renewable energy into the grid.In this paper,the working principle of solid oxide electrolysis cell,key materials and research status of electrolytic carbon dioxide and co-electrolysis in solid oxide electrolysis cell are comprehensively summarized.Through the discussion of the catalytic mechanism of CO₂ electrolysis and H₂O/CO₂ co-electrolysis,we recognize the nature of the conversion of carbon dioxide into carbon monoxide,water vapor and carbon dioxide into syngas,in order to better improve the performance of SOEC high temperature electrolysis.In this paper,Ni,Cu and NiCu are doped in rutile structure Nb₂TiO₇ with oxygen vacancy being constructed to replace traditional Ni matrix composites.Since Nb₂TiO₇ can be doped with a large amount of metal elements,the performance of the electrode material after doping is different from that of traditional metals.In this work,electrochemical performance indicates that Ni_xCu_1-x is a synergistic catalyst that can significantly increase CO₂ electrolysis performance.In a high temperature reducing atmosphere,the three-phase interface（TPB）formed by in-situ growth of Ni_x Cu_1-x alloy catalyst on the substrate of Nb_1.33(Ti_0.8Mn_0.2)_0.67O_4-x ceramic material can enhance the catalytic activity of the electrode material.The performance of electrolyzing carbon dioxide at high temperature reflects that the activity of the electrode material has a strong relationship with the composition of the alloy,That is,the interface formed by Ni_xCu_1-x/Nb_1.33(Ti_0.8Mn_0.2)_0.67O_4-x of different components is related to the electrochemical performance of the composite electrode.And the electrochemical performance of the composite electrode is related.CO₂ dissociation is the oxygen transfer process from the gas phase to the solid oxide phase at the three-phase interface,and the three-phase interface is mainly composed of the metal oxide interface in the hydrogen electrode.Here,our goal is to enhance the oxygen transfer process by controlling the structure and composition of the metal oxide interface to promote the reduction of CO₂ to CO.The oxygen transfer engineering significantly improved the electrolysis performance of CO₂.The results show that the electrochemical properties are strongly correlated with the alloy composition and oxygen vacancy co-control of metal nanoparticles grown in situ at the interface.Then,we co-electrolyze H₂O/CO₂ through a solid oxide electrolytic cell（SOEC）to produce syngas.In general,reversible solid oxide electrolysis cells（SOECs）can be used for the high-temperature H₂O/CO₂ co-electrolysis process to generate syngas with high efficiency.As the cathode materials,Sr₂Fe_1.5Mo_0.5O_6-δhas various choices of B-site cations in a wide range of compositions,offering flexibility in setting their properties.10%Fe is doped in the B-site of Sr₂Fe_1.5Mo_0.5O_6-δ.Furthermore,in situ grown Fe-ceramic composite cathode provides massive and efficient triple-phase boundary（TPB）for the H₂O/CO₂ co-electrolysis process after reduced.The Fe nanoparticles distributed on Sr₂Fe_1.5Mo_0.5O_6-δsubstrate are demonstrated by the X-ray diffraction（XRD）,the X-ray photoelectron spectroscopy（XPS）,the scanning electron microscopy（SEM）and high-resolution transmission electron microscopy（HRTEM）.The current density reaches 1.27 A cm^-2 at1.6 V and 850°C on the solid oxide Sr₂Fe_1.6Mo_0.5O_6-δ-SDC/LSGM/Sr₂Fe_1.5Mo_0.5O_6-δ-SDC cell.The highest current efficiency of⁹1%is harvested at 1.3 V.The cell shows highly stable long-term performance after 100 h operation.