A‐Site Management Prompts the Dynamic Reconstructed Active Phase of Perovskite Oxide OER Catalysts

Abstract

Perovskites (ABX3) are promising oxygen evolution reaction (OER) catalysts for their highly intrinsic activity. The in‐depth understanding and the adjustment of dynamic reconstruction of active phases for perovskites in OER are still a daunting challenge. Here, a refined A‐site management strategy is proposed for perovskite oxides, which facilitates the surface reconstruction of the B‐site element based active phase to enhance the OER performance. Electrocatalyst LaNiO3 displays a dynamic reconstruction feature during OER with the growth of a self‐assembled NiOOH active layer, based on the in situ electrochemical Raman technology. Precise A‐site Ce doping lowers the reconstruction potential for the active phase and the dynamic structure–activity correlation is well established. Theoretical calculations demonstrate that A‐site Ce substitution upshifts the O 2p level for greater structural flexibility with optimized oxygen vacancy content, thereby activating the B‐site atom and promoting the active phase reconstruction. These results suggest that A‐site management prompts the B‐site element based active phase dynamic reconstruction via engineered X‐site content as a bridge. Therefore, indicating the strong correlation of each‐site component in perovskite oxides during OER and deepening the understanding of the fundamental processes of the structural transformation and further benefiting the accurate design of high‐efficiency perovskite OER electrocatalysts.

An Efficient Symmetric Electrolyzer Based On Bifunctional Perovskite Catalyst for Ammonia Electrolysis

“…A‐site cation segregation on the surface has been widely observed in perovskite catalysts due to the unique surface environment, and it is commonly unfavorable for catalytic performance. [ 45 , 68 , 69 ] After the electrolysis test, the atomic ratio of B‐site/A‐site at the anode was almost unchanged (0.54). However, the ratio increased to 0.82 at the cathode side, which means A‐site cation segregation was suppressed and more B‐sites were evolved during the HER.…”

Enhanced Performance of Carbon–Selenide Composite with La0.9Ce0.1NiO3 Perovskite Oxide for Outstanding Counter Electrodes in Platinum-Free Dye-Sensitized Solar Cells

“…The synthesis of L perovskite oxide nanoparticles was performed following previous literature, by a hydrothermal synthesis method using a GNP [19,20]. First, 20 mmol of La(NO 3 ) 3 •6H 2 O (8.6602 g), 2.2 mmol of Ce(NO 3 ) 3 •6H 2 O (0.9553 g), and 22 mmol of Ni(NO 3 ) 2 •6H 2 O (6.3976 g) were added to 50 mL of DI water and stirred for 15 min.…”

“…LaNiO 3 is a simple and low-cost perovskite oxide that has drawn considerable attention in various fields thanks to its chemical stability, relatively high conductivity compared to other perovskite oxides, and also because it presents one of the highest oxygen reduction reaction activities reported for this kind of perovskite oxide [ 15 , 16 , 17 , 18 ]. Recently, Yu et al [ 19 ] demonstrated that partial replacement of La sites with Ce improves the performance of LaNiO 3 as oxygen evolution reaction catalysts by increasing the O 2p band center. This results in an appropriate amount of oxygen vacancy and enhanced structural flexibility.…”

Surface reconstruction establishing Mott-Schottky heterojunction and built-in space-charging effect accelerating oxygen evolution reaction

“…Besides, the position of the Ni oxidation peak slightly shifts positively, suggesting phase change from Ni(OH) 2 to NiOOH. Previous studies have demonstrated that the formation of NiOOH in the electrochemical process is a key step for improving electrochemical activity [36][37][38][39][40]. To verify the increased catalytic activity of F-Ni(OH) 2 after surface reconstruction, a series of LSV were performed in 1 M KOH solution after 50, 100, 150, 200, and 250 cycles CV treatment (Fig.…”