同型异质表面修饰提高La2NiO4+δ阴极的电催化活性

Improving the Electrocatalytic Activity of La2NiO4+δCathode by Surface Modification with Conformal Heterojunction

构建异质结界面来改性传统的阴极材料已广泛应用于提高固体氧化物燃料电池(SOFC)阴极氧还原反应(ORR)活性的研究。本文研究发现,在传统的La2NiO4+δ(LNO)阴极表面,表面修饰同型的Pr2NiO4+δ(PNO)薄膜能够有效地加速其ORR动力学。同时,也揭示了表面修饰提高ORR活性的机理。首先,调控工艺条件,LNO薄膜出现了高催化活性的(110)晶面。其次,厚度约为5 nm的PNO外延层沉积在LNO表面显示出最小的极化电阻,其极化电阻比相同厚度LNO参照的小近21倍。由于异质结表面氧缺陷化学的不同,PNO(~5 nm)表面修饰的异质结表现出优越的ORR活性。其中,多孔的LNO本体提供了一条有利于传输氧离子和电子的途径,而PNO修饰提供了丰富的表面氧缺陷,从而进一步增强了阴极的ORR活性。

Tuning the existing cathode surface to construct a hetero-interface configuration has been widely applied to improve its oxygen reduction reaction(ORR)activity.Here we report our findings on effective acceleration of the ORR kinetics of La 2 NiO 4+δ(LNO)cathode by conformal Pr 2 NiO 4+δ(PNO)modification.Meanwhile,the mechanism of the surface modification on ORR activity is revealed.Firstly,a highly active(110)plane for oxygen reduction emerges under LNO deposition.Secondly,the PNO modified layer with^5 nm thick displays the smallest polarization resistance,which is 21 times less than that of LNO(~5 nm)referenced cathode.Meanwhile,PNO(~5 nm)heterojunction exhibits an alerted ORR kinetics because of different oxygen defect chemistries of the top layer,in which the porous LNO backbone provides a pathway to favorably transport both of oxygen ions and electrons,while the PNO decorating offers rich surface oxygen defects to further enhance the ORR activity.