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Designing efficient Ruthenium-based catalysts as practical anodes is of critical importance in proton exchange membrane water electrolysis. Here, we develop a self-assembly technique to synthesize 1 nm-thick rutile-structured high-entropy oxides (RuIrFeCoCrO2) from naked metal ions assembly and oxidation at air-molten salt interface. The RuIrFeCoCrO2 requires an overpotential of 185 mV at 10 m A cm−2 and maintains the high activity for over 1000 h in an acidic electrolyte via the adsorption evolution mechanism. We discuss the role of each element in the RuIrFeCoCrO2 and find that the Cr, Co, and Ir sites contribute to the catalytic activity, while the Cr atoms weaken the Ru-O bond covalency and improves the catalyst stability. The assembled proton exchange membrane electrolyzer operates stably for more than 600 h at a large current of 1 A cm−2. The naked ion assembly demonstrated in this work may provide an effective pathway for the controlled synthesis of a diversity of high-entropy materials. Designing efficient ruthenium-based catalysts as practical anodes is important for proton exchange membrane electrolysis. Here, the authors report a self-assembly technique to synthesize atomically thin high-entropy oxides from the assembly of naked metal ions for hydrogen generation. [ABSTRACT FROM AUTHOR]

Zn metal is a promising anode material in aqueous batteries, but the direct use of Zn foil encounters severe issues of dendrite formation and side reactions, causing short cycle life. Conventional thick and rigid insulating protection layers may impede Zn ion diffusion and detach during mechanical deformation of the battery. Herein, a dendrite‐free zinc anode is demonstrated by grafting a thin (≈10 nm) Ti3C2Tx MXene functional membrane which is formed via Marangoni‐driven self‐assembly. The thin MXene membrane initiates uniform nucleation and promotes deposition of (002)‐oriented Zn in a lateral growth mode. Meanwhile, the membrane functions as a soft, stress‐adaptive, and protective layer to the underneath active zinc. This functional membrane renders Zn anode with improved cycling stability without notable dendrite formation or side‐reaction products. Flexible Zn─I2 pouch cells fabricated from the MXene‐covered Zn foil (20 µm thick) anode and a modified ZnI2 cathode demonstrate stable capacity up to 1500 cycles and unchanged voltage upon various mechanical deformations. This work affords new insights into designing functional soft membranes for constructing flexible Zn‐based energy devices. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) are key reactions in diverse energy conversion devices, highlighting the importance of efficient catalysts. Edge‐anchored single atom catalysts (E‐SACs) emerge as a special class of atomic structure, but the detailed configuration and its correlation with catalytic activity remain little explored. Herein, a total of 78 E‐SACs (E‐TM‐Nx‐C) have been constructed based on 26 transition metal (TM) species with three coordination patterns. Using structural stability and ORR/OER catalytic activity as the evaluation criteria, a few catalytic structures comparable to Pt (111) for ORR and IrO2 (110) for OER are screened based on high‐throughput calculations. The screening results unveil that the E‐Rh‐N4‐C configuration exhibits most efficient bifunctional activity for both ORR and OER with an overpotential of 0.38 and 0.61 V, respectively. Electronic structure analysis confirms the distinctive edge effects on the electronic properties of TM and N species, and the feature importance derived from machine learning illustrates the efficacy of E‐TM‐Nx subunit configuration in determining the catalytic activity of E‐SACs. Finally, the trained Gradient Boosting Regression (GBR) model exhibits acceptable accuracy in predicting the OH intermediates adsorption strength for E‐SACs, thereby paving the way for expanding catalytic structures based on E‐SACs. [ABSTRACT FROM AUTHOR]

It is important to tune the coordination configuration of dual‐atom catalyst (DAC), especially in the first coordination sphere, to render high intrinsic catalytic activities for oxygen reduction/evolution reactions (ORR/OER). Herein, a type of atomically dispersed and boron‐coordinated DAC structure, namely, FeN4B‐NiN4B dual sites, is reported. In this structure, the incorporation of boron into the first coordination sphere of FeN4/NiN4 atomic sites regulates its geometry and electronic structure by forming "Fe‐B‐N" and "Ni‐B‐N" bridges. The FeN4B‐NiN4B DAC exhibits much enhanced ORR and OER property compared to the FeN4‐NiN4 counterparts. Density functional theory calculations reveal that the boron‐induced charge transfer and asymmetric charge distributions of the central Fe/Ni atoms optimize the adsorption and desorption behavior of the ORR/OER intermediates and reduce the activation energy for the potential‐determining step. Zinc‐air batteries employing the FeN4B‐NiN4B cathode exhibit a high maximum power density (236.9 mW cm−2) and stable cyclability up to 1100 h. The result illustrates the pivotal role of the first‐coordination sphere of DACs in tuning the electrochemical energy conversion and storage activities. [ABSTRACT FROM AUTHOR]