Operando X-ray absorption spectroscopy (XAS) technique unravels that the CoFe nanoparticles in a new type of lanthana-anchored CoFe catalyst are nearly transformed into unique (Co/Fe)O(OH) under the electrochemical condition, as real active species for oxygen evolution reaction.

Tuning material properties by modulation of the arrangement of atoms is a fundamental and effective strategy in materials science. Structurally long‐range ordered materials are increasingly finding utility for electrocatalytic applications. Such ordered structures can achieve unique functions that increase the electrocatalytic activity compared to corresponding electrocatalysts with a disordered structure. Effective strategies for designing high‐performance electrocatalysts based on structurally ordered materials are presented. This review also summarizes the recent progress on structurally ordered materials as efficient electrocatalysts and highlights the applications in several representative electrochemical reactions, such as, the oxygen evolution reaction, oxygen reduction reaction, and hydrogen evolution reaction. The structural features of the atomic long‐range ordered framework and superior electrochemical performance are demonstrated by advanced characterization techniques (structural identification) and electrochemical measurements (performance evaluations), respectively. Special attention is paid to the establishment of a structure‐activity relationship to highlight the advantages of the ordered structure. Finally, the remaining challenges and emerging opportunities in these related materials are proposed.

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Identifying real active sites and understanding the mechanism of oxygen evolution reaction (OER) are still a big challenge today for developing efficient electrochemical catalysts in renewable energy technologies. Here, using a combined in situ/operando experiments and theory, the catalytic mechanism of the ordered OER active Co and Ir ions in Sr2CoIrO6−δ is studied, which exhibits an unprecedented low overpotential 210 mV to achieve 10 mA cm–2, ranking the highest performance among perovskite‐based solid‐state catalysts. Operando X‐ray absorption spectroscopies as a function of applied voltage indicates that Ir4+ ion is gradually converted into extremely high‐valence Ir5+/6+, while the part of Co3+ ion is transferred into Co4+ under OER process. Density functional theory calculations explicitly reveal the order Co‐O‐Ir network as an origin of ultrahigh OER activity. The work opens a promising path to overcome the sluggish kinetics of OER bottleneck for water splitting via proper arrangements of the multi‐active sites in catalyst.

Spinel cobalt-based oxides are a promising family of materials for water splitting to replace currently used noble-metal catalysts. Identifying the highly active facet and the corresponding coordinated structure of surface redox centers is pivotal for the rational design of low-cost and efficient nanosized catalysts. Using high-resolution transmission electron microscopy and advanced X-ray techniques, as well as ab initio modeling, we found that the activity of Co3+ ions exhibits the surface dependence owing to the variability of its electronic configurations. Our calculation shows that the Co3+ site in {100} facet of nanosized Li2Co2O4 exhibits an impressive intrinsic activity with low overpotential, far lower than that of the {110} and {111} facets. The unique, well-defined CoO5 square-pyramidal structure in this nonpolar surface stabilizes the unusual intermediate-spin states of the Co3+ ion. Specially, we unraveled that oxygen ion anticipates the redox process via the strong hybridization Co 3d–O 2p state, which produces a 3d z 21.1 filling orbit. Finally, a spin-correlated energy diagram as a function of Co–O distance was devised, showing that the covalency of Co–O significantly affects the spin state of Co3+ ions. We suggest that the nonpolar surface that contains CoO5 units in the edge-sharing systems with the short Co–O bond distance is a potential candidate for alkaline water electrolysis.

Urea oxidation reaction (UOR) with a low equilibrium potential offers a promising route to replace the oxygen evolution reaction for energy-saving hydrogen generation. However, the overpotential of the UOR is still high due to the complicated 6e − transfer process and adsorption/desorption of intermediate products. Herein, utilizing a cation exchange strategy, Ni-doped CuO nanoarrays grown on 3D Cu foam are synthesized. Notably, Ni-CuO NAs/CF requires a low potential of 1.366 V versus a reversible hydrogen electrode to drive a current density of 100 mA cm −2 , outperforming various benchmark electrocatalysts and maintaining robust stability in alkaline media. Theoretical and experimental studies reveal that Ni as the driving force center can effectively enhance the urea adsorption and stabilize CO*/NH* intermediates toward the UOR. These findings suggest a new direction for constructing nanostructures and modulating electronic structures, ultimately developing promising Cu-based electrode catalysts.