原位析出制备固体氧化物电解池的"氧化铈–金属–钙钛矿"复合阴极材料

In-situ Exsolution of Cerium Oxide-Metal-Perovskite Composite Cathode for Solid Oxide Electrolysis Cell

固体氧化物电解池能够利用可再生电能将CO_(2)转化为CO等储存,但其阴极材料仍面临活性位易烧结和积碳等问题.通过原位析出策略在A位缺陷钙钛矿阴极材料La_(0.4)Ca_(0.4)Ti_(0.94)Ni_(0.06)O_(3–δ)表面构筑金属Ni纳米颗粒,并优化不同的合成手段(掺杂、浸渍、混合)引入CeO_(2),构筑了"氧化铈–金属–钙钛矿"三相复合阴极.结果表明:机械混合CeO_(2)对阴极的抗积碳性能与电化学性能的提升最为显著:在800℃,70%(体积分数)CO_(2)/30%CO,1.4 V电解电压下,电流密度提高3倍,衰减速率降低58%,该改性结果与其表面氧空位浓度增加及CO_(2)吸附强化有关.

The solid oxide electrolytic cell can use a renewable electricity to convert CO_(2)into CO for storage.However,it still suffers from the sintering of reactive sites and carbon deposition at cathode.In this work,A-site deficient La_(0.4)Ca_(0.4)Ti_(0.94)Ni_(0.06)O_(3-δ)perovskite cathode with the decoration of a large number of exsolved Ni nanoparticles was prepared by an in-situ exsolution method.Also,a promoter of CeO_(2)was introduced into the system via different synthetic methods(i.e.,doping,impregnation and mechanical mixing)to construct a"cerium oxide-metal-perovskite"three-phase composite cathode material.The results show that the carbon deposition resistance and electrochemical performance of the mechanical mixed modified materials can be improved at 800C,70%(in volume)CO2/30%CO and 1.4 V electrolytic voltage.The current density is increased by 3 times and the voltage decay rate is decreased by 58%.Such an improvement is correlated to the increased amount of surface oxygen vacancies and the strengthened CO_(2)absorption.