Oxidation and Storage Mechanisms for Nitrogen Oxides on Variously Terminated (001) Surfaces of SrFeO3-δ and Sr3Fe2O7-δ Perovskites
Oxidation and Storage Mechanisms for Nitrogen Oxides on Variously Terminated (001) Surfaces of SrFeO3-δ and Sr3Fe2O7-δ Perovskites
复制标题
SrFeO3-δ和Sr3Fe2O7-δ钙钛矿不同端接(001)表面上氮氧化物的氧化和存储机制
DOI：
10.1021/acsami.0c20724
复制
发表时间：
2021
影响因子：
9.5
通讯作者：
Fukuda Ryoichi
中科院分区：
文献类型：
--
作者：
Takamatsu Akihiko;Tamai Kazuki;Hosokawa Saburo;Tanaka Tsunehiro;Ehara Masahiro;Fukuda Ryoichi
Ruddlesden-Popper （RP）型层状钙钛矿是一种新型氮氧化物（NOx）储存催化剂的候选材料。本文通过密度泛函理论（DFT）计算，研究了rp型氧化物Sr3Fe2O7−δ在所有末端的（001）表面对NOxon的吸附和氧化，并与简单钙钛矿SrFeO3−δ进行了比较。sr3fe2o7可能的（001）解理产生2个FeO2-终止面和3个sro -终止面，计算的表面能表明，岩盐层解理产生的sro -终止面是最稳定的。feo2末端表面的氧可以用很低的能量去除，因为该过程涉及Fe4+位置的有利还原。因此，feo2位点的表面氧很容易通过Mars-van Krevelen机制将吸附的NO氧化为no2。由此产生的表面氧空位很容易被大量的晶格氧填充。在Langmuir-Hinshelwood和ely - rideal机制下，吸附的o2分子氧化NO是不利的，因为这一过程不涉及Fe4+位点的还原。sro端部表面的氧紧密结合，成为NO和NO2的吸附位点。电子转移通过形成亚硝酸盐（NO2 -）或硝酸盐（NO3 -）加强了nox与表面的结合。DFT计算表明，rp型结构通过jhn - teller畸变形成活性氧和岩盐层解理暴露sro终止表面来促进氧化和储存性能。
The Ruddlesden–Popper (RP)-type layered perovskite is a candidate material for a new nitrogen oxide (NOx) storage catalyst. Here, we investigate the adsorption and oxidation of NOxon the (001) surfaces of RP-type oxide Sr3Fe2O7−δfor all of the terminations by comparing to those of simple perovskite SrFeO3−δby the density functional theory (DFT) calculations. The possible (001) cleavages of Sr3Fe2O7generate two FeO2- and three SrO-terminated surfaces, and the calculated surface energies indicated that the SrO-terminated surface generated by the cleavage at the rock salt layer is the most stable one. The oxygen of the FeO2-terminated surfaces could be removed with significantly low energy because the process involves the favorable reduction of the Fe4+site. Consequently, the surface oxygen at the FeO2site could easily oxidize adsorbed NO to NO2by the Mars–van Krevelen mechanism. The resulting oxygen vacancy in the surface would be filled easily with lattice oxygen in bulk. The oxidation of NO with adsorbed molecular O2was unfavorable by both the Langmuir–Hinshelwood and Eley–Rideal mechanisms because this process does not involve the reduction of the Fe4+site. The oxygen of the SrO-terminated surfaces was tightly bound and acted as the adsorption site of NO and NO2. An electron transfer strengthened the NOxbinding to the surface by forming nitrite (NO2–) or nitrate (NO3–) species. The DFT calculations revealed that the RP-type structure promoted NOxoxidation and storage properties by forming active oxygen due to the Jahn–Teller distortion and by exposing SrO-terminated surfaces due to the cleavage at the rock salt layer.