Effects of paramagnetic fluctuations on the thermochemistry of MnO(100) surfaces in the oxygen evolution reaction

Atomic Reconstruction and Oxygen Evolution Reaction of Mn3O4 Nanoparticles

Understanding the chemical states of individual surface atoms and their arrangements is essential for addressing several current issues such as catalysis, energy stroage/conversion, and environmental protection. Here, we exploit a profile imaging technique to understand the correlation between surface atomic structures and the oxygen evolution reaction (OER) in Mn₃O₄ nanoparticles. We image surface structures of Mn₃O₄ nanoparticles and observe surface reconstructions in the (110) and (101) planes. Mn³⁺ ions at the surface, which are commonly considered as the active sites in OER, disappear from the reconstructed planes, whereas Mn³⁺ ions are still exposed at the edges of nanoparticles. Our observations suggest that surface reconstructions can deactivate low-index surfaces of Mn oxides in OER. These structural and chemical observations are further validated by density functional theory calculations. This work shows why atomic-scale characterization of surface structures is crucial for a molecular-level understanding of a chemical reaction in oxide nanoparticles.

Autologous manganese phosphates with different Mn sites for electrocatalytic water oxidation

Herein, we report two autologous phosphates obtained from the same parent material for electrocatalytic water oxidation. These two phosphates have many similarities except the coordination structure of the Mn centers. It has been straightforwardly observed that the highly asymmetric geometry of Mn2P2O7 can stabilize the active Mn(iii) to promote water oxidation.