Na Yao

Different interfacial configurations in ruthenium oxide (RuO _x ) composites lead to variations in orbital structures and catalytic performance. Therefore, understanding the role of these interfaces in the acidic oxygen evolution reaction (OER) is crucial for designing more stable Ru‐based catalysts. Here, single‐atom RuO _x (Ru _SA O _x ), sub‐nanoclusters (Ru _SNC O _x ), and heterostructures (RuO _x ) were incorporated into cerium oxide (CeO _x ) to construct three distinct interfaces (i.e., Ce–Ce‐Ce‐Ru, Ce‐Ru‐Ru‐Ce, and Ce‐Ce‐Ru‐Ru), enabling a systematic evaluation of their effects on acidic OER performance. Combining in situ and ex situ spectroscopies, including attenuated total reflection surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS), ultraviolet–visible spectroscopy (UV–vis), Raman spectroscopy, differential electrochemical mass spectrometry (DEMS), and other characterization techniques with density functional theory (DFT) calculations reveals that the Ru _SNC O _x ‐CeO _x interface induces additional π orbitals. Electron delocalization between these π orbitals and *O intermediates increases *O coverage and suppresses *O‐*O repulsion, which promotes the OPM pathway. The electron delocalization by π orbitals also optimizes interfacial water and hydrogen‐bond networks, as well as accelerates deprotonation, sustains *O supply, and mitigates Ru over‐oxidation, collectively enhancing OER kinetics and durability. As a result, Ru _SNC O _x ‐CeO _x requires only 178 mV to reach 10 mA cm ⁻² in 0.5 M H ₂ SO ₄ and remains stable for over 1000 h. In proton exchange membrane (PEM) electrolyzers, it outperforms conventional RuO ₂ , sustaining 1 A cm ⁻² for more than 1000 h.

The ever-increasing consumption of fossil fuels has led to environmental crises, which accelerated the quest for sustainable hydrogen energy. Among various production routes, water electrolysis stands out as a promising approach. However, the efficiency of hydrogen evolution reaction is limited by the adhesion of gas bubbles on electrode surfaces, which blocks active sites, increases overpotential, and limits mass transfer. This review highlights the design of micro/nanostructured array electrodes to achieve underwater superaerophobicity, reducing bubble adhesion, facilitating the nucleation and rapid release of ultrasmall bubbles, thereby contributing to reduce in overpotential, faster bubble growth, enhanced mass transport, and improved catalyst stability. We summarize recent advances in fabrication strategies of such electrodes, focusing on micro/nanostructural designs, covering from 0 to 3-dimensional structures. Additionally, the role of hydrophilic gels in optimizing superaerophobicity is discussed. Finally, challenges and future directions are addressed, including bubble dynamics accurate modeling, development of high activity and stability catalysts, intelligent adaptive electrode structure and active bubble regulation, and the integration of artificial intelligence and deep learning for guided electrode design. This review aims to provide a comprehensive perspective on how superaerophobic electrode design address bottlenecks in gas-evolving electrodes, paving the way toward more efficient and economical hydrogen production.

Understanding the effect of noncovalent interactions of intermediates at the polarized catalyst‐electrolyte interface is key to improving the kinetics of electrocatalytic reactions. Herein, we employ cobalt oxyhydroxide (CoOOH) as a model catalyst, select carboxylate‐based additives to strategically modulate the interfacial electronic double layer (EDL), and investigate the effect of carboxylate anions on the oxygen evolution reaction (OER) kinetics under alkaline media. We demonstrate that the hydrogen bonds formed between oxygen atoms within ‐COO ⁻ fragments of carboxylate anions and interfacial H ₂ O molecules can disrupt the arrangement of the hydration shell around K ⁺ , leading to fast migration of OH ⁻ to the CoOOH surface. Experimental results, including rotating ring‐disk electrode (RRDE) measurements, in situ X‐ray absorption spectroscopy (XAS), in situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS), and ab initio molecular dynamics (AIMD) theory simulations, reveal that the negative electrostatic potential on the oxygen atom in the ‐COO ⁻ fragments can partially neutralize the localized electric field generated by hydrated K ⁺ ions in the electrolyte, which sufficiently destabilizes the adsorbed oxygenated intermediates and accelerates the deprotonation process, thereby leading to promoted charge accumulation and accelerated alkaline OER kinetics.

Understanding the effect of noncovalent interactions of intermediates at the polarized catalyst‐electrolyte interface is key to improving the kinetics of electrocatalytic reactions. Herein, we employ cobalt oxyhydroxide (CoOOH) as a model catalyst, select carboxylate‐based additives to strategically modulate the interfacial electronic double layer (EDL), and investigate the effect of carboxylate anions on the oxygen evolution reaction (OER) kinetics under alkaline media. We demonstrate that the hydrogen bonds formed between oxygen atoms within ‐COO ⁻ fragments of carboxylate anions and interfacial H ₂ O molecules can disrupt the arrangement of the hydration shell around K ⁺ , leading to fast migration of OH ⁻ to the CoOOH surface. Experimental results, including rotating ring‐disk electrode (RRDE) measurements, in situ X‐ray absorption spectroscopy (XAS), in situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS), and ab initio molecular dynamics (AIMD) theory simulations, reveal that the negative electrostatic potential on the oxygen atom in the ‐COO ⁻ fragments can partially neutralize the localized electric field generated by hydrated K ⁺ ions in the electrolyte, which sufficiently destabilizes the adsorbed oxygenated intermediates and accelerates the deprotonation process, thereby leading to promoted charge accumulation and accelerated alkaline OER kinetics.

An In-doping Lewis base strategy stabilizes the lattice oxygen mechanism in RuO ₂ . By tuning interfacial water and oxygen vacancies, In-RuO ₂ yields 194 mV @ 10 mA cm ⁻² for acidic OER and >1000 h stability @ 1 A cm ⁻² in PEM electrolyzers.

Although cobalt spinel oxide-based catalysts have demonstrated promising performance for the oxygen evolution reaction in acid, strategies reported have largely focused on manipulating the binding energies of reaction intermediates through tailoring the inherent electronic structures. The role of interfacial water structures on the electrode surface in promoting the acidic oxygen evolution reaction performance through controlled water activation has been largely overlooked. Here we show that introducing chromium dopant into cobalt spinel oxide can simultaneously increase the activity and stability by promoting interfacial water dissociation and dynamic electron transfer. The chromium dopant can not only dynamically regulate the electronic structure of cobalt and mitigate the over-oxidation of active cobalt sites at high overpotential, but also enhance the coverage of hydroxyl species on the catalyst surface, thereby optimizing the interfacial water structure, accelerating the reactant free-water supply and promoting subsequent interfacial water dissociation. Consequently, the obtained catalyst demonstrates enhanced performance in both solution electrocatalysis and device electrocatalysis. This work provides a comprehensive understanding of enhancing the acidic oxygen evolution reaction performance by promoting interfacial water dissociation.

This study reveals a strong Ru structural effect. Subnanometer Ru clusters (Ru _SNCs -WO _x ) regulate interfacial water via d–π coupling, promoting water dissociation and *OH formation, and then facilitates *O–*O coupling.

Tailoring the characteristics of hydroxyl intermediates ( ^* OH) on Ru‐based catalysts is vital for modulating catalytic pathways and optimizing their performance for water oxidation (OER); however, their modulation mechanisms and roles remain a significant challenge. Here, a strategy is proposed to regulate the ^* OH adsorption behavior of Ru‐based catalysts by designing RuMo@RuMoO _x electrocatalysts with strong metal‐support interactions and built‐in charge gradients. Quasi‐in‐situ/operando characterization and theoretical calculations reveal that this design effectively promotes the adsorption of ^* OH at Ru sites, optimizes the orientation of ^* OH, and facilitates ^* OH spillover to the adjacent Mo sites via charge gradients between the Ru and Mo sites. This process initiates a hydroxyl migration‐coupled mechanism (HMCM), which breaks the ^* OH‐ ^* OOH scaling relation, alters the rate‐determining step (RDS), and stabilizes OER intermediates, thereby boosting the OER performance. The RuMo@RuMoO _x catalyst exhibits low overpotentials of 166, 200, and 199 mV in 0.5 M H ₂ SO ₄ , 1 M KOH, and 1 M PBS, respectively, at 10 mA cm ⁻² , along with an outstanding stability of over 1000 h of operation. Furthermore, the RuMo@RuMoO _x catalyst demonstrates a lower overpotential than RuO ₂ and maintains stable operation for over 1000 h in a PEM water electrolyzer at 1 A cm ⁻² .