Proton Exchange Membrane Water Electrolysis (PEMWE) under acidic conditions outperforms alkaline water electrolysis in terms of less resistance loss, higher current density, and higher produced hydrogen purity, which make it more economical in long-term applications. However, the efficiency of PEMWE is severely limited by the slow kinetics of anodic oxygen evolution reaction (OER), poor catalyst stability, and high cost. Therefore, researchers in the past decade have made great efforts to explore cheap, efficient, and stable electrode materials. Among them, the RuO₂ electrocatalyst has been proved to be a major promising alternative to Ir-based catalysts and the most promising OER catalyst owing to its excellent electrocatalytic activity and high pH adaptability. In this review, we elaborate two reaction mechanisms of OER (lattice oxygen mechanism and adsorbate evolution mechanism), comprehensively summarize and discuss the recently reported RuO₂-based OER electrocatalysts under acidic conditions, and propose many advanced modification strategies to further improve the activity and stability of RuO₂-based electrocatalytic OER. Finally, we provide suggestions for overcoming the challenges faced by RuO₂ electrocatalysts in practical applications and make prospects for future research. This review provides perspectives and guidance for the rational design of highly active and stable acidic OER electrocatalysts based on PEMWE.

In vivoandin vitrostudies show that chlorogenic acid methyl ester (CME) has been proven to be a potential nutraceutical for preventing inflammation.

Atomically-dispersed iron-based electrocatalysts are promising substitutes for noble metal electrocatalysts because of excellent performance in oxygen reduction reaction (ORR). Rationally modulating the local coordination environment of the Fe site and optimizing the binding energy of oxygen reduction intermediates are effective strategies to optimize ORR activity. Herein, we report a new method in which Ni is introduced to construct NiFe dual single atoms and iron nanoclusters loaded on the nitrogen-doped carbon with a highly porous structure. This design plays a synergistic role of dual single atoms and clusters, optimizes the 3d orbital and Fermi level of Fe, breaks the symmetrical structure of Fe-N₄, and effectively improves the adsorption/desorption behavior of the oxygen-containing intermediates. Electrochemical tests show Fe_NCs/NiFe_SAs-NC has an excellent intrinsic activity. Theoretical calculations show the oxygen-containing species on the Ni active site will move to the middle of NiFe (bridge site connection) after optimization and that the key step is OH desorption, with a reaction energy of 0.27 eV. The electron exchange between NiFe-N₆ and Fe-cluster is very strong, further indicating the introduction of Ni species and Fe clusters has a regulatory effect on the electronic structure of Fe-N₄.