In Situ Modulation of A‐Site Vacancies in LaMnO_3.15 Perovskite for Surface Lattice Oxygen Activation and Boosted Redox Reactions

Abstract

Modulation of A‐site defects is crucial to the redox reactions on ABO3 perovskites for both clean air application and electrochemical energy storage. Herein we report a scalable one‐pot strategy for in situ regulation of La vacancies (VLa) in LaMnO3.15 by simply introducing urea in the traditional citrate process, and further reveal the fundamental relationship between VLa creation and surface lattice oxygen (Olatt) activation. The underlying mechanism is shortened Mn−O bonds, decreased orbital ordering, promoted MnO6 bending vibration and weakened Jahn–Teller distortion, ultimately realizing enhanced Mn‐3d and O‐2p orbital hybridization. The LaMnO3.15 with optimized VLa exhibits order of magnitude increase in toluene oxidation and ca. 0.05 V versus RHE (reversible hydrogen electrode) increase of half‐wave potential in oxygen reduction reaction (ORR). The reported strategy can benefit the development of novel defect‐meditated perovskites in both heterocatalysis and electrocatalysis.

Oxygen vacancies in a catalyst for VOCs oxidation: synthesis, characterization, and catalytic effects

“…91–93 In addition to investigating the coordination information of noble metals by fitting and analyzing the XAFS data, it has been used to study defects in non-noble metals in recent years. 94 Fig. 5A shows that Co 3 O 4 with different morphologies (rod-, sheet-, and cube-like) exhibited discrepant post-edge oscillation amplitudes.…”

Restraining lattice oxygen of Cu2O by enhanced Cu–O hybridization for selective and stable production of ethylene with CO2 electroreduction

“…2a, the single peak located between 350 and 650 °C in the O 2 -TPD curve represents the release of the lattice oxygen. 41 Apparently, B–Cu 2 O-1 has the lowest oxygen desorption temperature of 350 °C, while the peak value of O 2 -TPD gradually increases along with the increase in the B-doping content of B–Cu 2 O-2, B–Cu 2 O-3 and B–Cu 2 O-4, respectively. The higher temperature required for the oxygen desorption indicates more stabilized lattice oxygen in the sample.…”

Acid Etching-Induced In Situ Growth of λ-MnO2 over CoMn Spinel for Low-Temperature Volatile Organic Compound Oxidation

“…The optimized models before and after acid etching are shown in Figure S5. With the removal of Co atoms, the adjacent Mn–O bond length was shortened from 1.91 to 1.86 Å (Figure S5), which was conducive to the rapid transfer of the interfacial charge to the reaction site . Bader charge analysis (Table S7) found that the electron cloud density around O atoms decreased after the Co–O bond was broken, which might lead to the weakening of the adjacent Mn–O bond .…”