Ya Yan

Soft bioelectronics require conductive hydrogels with balanced mechanical–electrical performance for high‐fidelity electrophysiological recording, yet conventional ones lack a balance between stretchability and electrochemical stability due to poor interfacial charge transfer. We present a molecularly engineered polyoxometalate‐functionalized mesoporous metal–organic framework (meso‐MOF@POM) nanoarchitecture that simultaneously reinforces the hydrogel network and enhances interfacial charge kinetics. The meso‐MOF serves as a hierarchical scaffold with multiscale channels for polymer anchoring, while the sub‐nanometer Keggin‐type POM layer creates abundant redox‐mediated electron transfer pathways. Upon integration of meso‐MOF@POM into a dual‐network poly(acrylic acid)/polyacrylamide hydrogel, the composite hydrogel enables high stretchability (>1000% strain), minimal electrical creep (3000 cycles). Crucially, the engineered organic–inorganic interface endows the hydrogel with excellent pseudocapacitive charge‐transfer kinetics, which achieves low skin–electrode impedance (64 kΩ at 1 Hz vs. 287 kΩ at 1 Hz for Ag/AgCl gel). As a result, the skin‐interfacing electrode enables high‐fidelity recording of on‐skin electrophysiological signals, including electrocardiogram, electromyogram, and electrooculogram, with an enhanced signal‐to‐noise ratio (e.g., 23.8 dB for ECG vs. 21.3 dB for Ag/AgCl gel). This work provides a novel fabrication strategy for highly conductive interfaces, enabling long‐term applications in wearable health monitors and human–machine interfaces.

Activation and cleavage of the inert O═O bond represent a central challenge in energy electrochemistry. Here, the Cu dual‐atom catalyst (Cu‐DAC) is constructed via bottom‐up pre‐coordination assembly and post‐encapsulation pyrolysis. The resulting Cu‐DAC features a well‐defined Cu–Cu distance (∼3.31 Å) with switchable Cu ¹⁺ /Cu ²⁺ states, enabling dynamic dual‐site coordination with O ₂ . Cu‐DAC achieves 0.87 V _RHE half‐wave potential for oxygen reduction reaction (ORR), a near‐unity 4e ⁻ selectivity, and outstanding stability. Multiple operando spectroscopic characterizations and ab initio dynamic simulations (AIMD) reveal that the dynamic heterovalent [Cu ^1+─ O─O ^{· −} ─Cu ²⁺ ] unit elongates the O–O bond and promotes its cleavage via dual‐site confinement and electron donation. By specifically elucidating how these dual‐atom sites dynamically evolve to facilitate O─O bond cleavage, we provide vital atomic‐level principles for the rational design of dynamically active catalysts.

Activation and cleavage of the inert O═O bond represent a central challenge in energy electrochemistry. Here, the Cu dual‐atom catalyst (Cu‐DAC) is constructed via bottom‐up pre‐coordination assembly and post‐encapsulation pyrolysis. The resulting Cu‐DAC features a well‐defined Cu–Cu distance (∼3.31 Å) with switchable Cu ¹⁺ /Cu ²⁺ states, enabling dynamic dual‐site coordination with O ₂ . Cu‐DAC achieves 0.87 V _RHE half‐wave potential for oxygen reduction reaction (ORR), a near‐unity 4e ⁻ selectivity, and outstanding stability. Multiple operando spectroscopic characterizations and ab initio dynamic simulations (AIMD) reveal that the dynamic heterovalent [Cu ^1+─ O─O ^{· −} ─Cu ²⁺ ] unit elongates the O–O bond and promotes its cleavage via dual‐site confinement and electron donation. By specifically elucidating how these dual‐atom sites dynamically evolve to facilitate O─O bond cleavage, we provide vital atomic‐level principles for the rational design of dynamically active catalysts.

To explore the effects of polyoxometalates modification on layered double hydroxides (LDHs) and metal‐organic frameworks (MOFs), we prepared the H ₅ PW ₁₀ V ₂ O ₄₀ ‐modified CoFe‐LDH and CoFe‐MOF composites via solvothermal method. Notably, the MOF/POM composite achieves a lower overpotential of 340 mV at 1 A·cm ⁻² in alkaline media and more excellent stability of a voltage of 1.90 V at 1 A·cm ⁻² for over 800 h in the anion exchange membrane water electrolyzer than the LDH/POM, benefiting from stronger electronic interaction, and the lower potential for active‐phase formation indicates faster catalytic activation. This work compares the effects of polyoxometalates on LDHs and MOFs, clarifying their differences.

The development of stable Ru-based anodes for acidic proton exchange membrane water electrolysis is promising, but strictly limited by Ru over-oxidation and structural collapse due to lattice oxygen participation under high current densities. Rational design of competitive Ru-based catalyst is, thereby, highly desired. Here, by exploring a customized self-assembly route, we report a type of mesoporous Ru-Ti-O solid solution catalyst delivering competitive performance (1 A cm^-2 for over 450 h at 0.4mg_Rucm^-2). Mechanistic investigations reveal that the enhanced performance arises from the integration of atomic-scale electronic structure tuning and mesoscopic triple phase interface engineering. The electron delocalization forms a conductive network and suppresses Ru overoxidation through electron donation. Atomically dispersed Ru-O-Ti motifs favor the oxygen pathway mechanism over the lattice oxygen mechanism, suppressing lattice oxygen release and enhancing structural stability. Simultaneously, the ordered mesoporous architecture and radially aligned nanorod bundles establish a robust, super-hydrophilic triple phase interface, enabling effective water and gas exchange and mitigating concentration overpotentials. This cross-scale design strategy offers a possible route to non-Ir catalysts with measurable activity and long-term durability for scalable acidic water electrolysis.

Electrochemical NO_x^- reduction offers an attractive approach for the sustainable production of ammonia (NH₃). Copper (Cu)-based materials are commonly used catalysts but suffer from a complex reaction pathway and low NH₃ selectivity. Herein, we report an electron delocalization strategy by inducing oxygen vacancy and chlorine (Cl) coordination sites as a dual modulator for the active Cu sites. Our model catalyst (Cu₂O_1-xCl₂) could deliver high NH₃ yields over a wide potential window, with a maximum NH₃ yield rate of 10.05 mg h^-1 cm^-2 and a Faradaic efficiency (FE) of 95.1%, exceeding most reported metal catalysts. A combination of experimental and theoretical investigations reveals that the dual modulator induces a favorable electron delocalization around the active Cu sites, resulting in an alteration of the rate-determining step (RDS) from NO₂* hydrogenation to the one proton-electron coupling of NO* to form NOH*. This thus enables rapid hydrogenation, avoids the occurrence of side reactions, and significantly improves the selectivity and yield of NH₃. When assembled into a membrane electrode electrolyzer, the cell can achieve an industrial current density of 340 mA cm^-2 with an NH₃ production rate of about 21.36 mg h^-1 cm^-2 and stably operates for up to 200 h. This RDS regulation strategy provides an innovative solution for enhancing the selectivity and efficiency of target products in electrocatalysis.

Stable, nonprecious catalysts are vital for large-scale alkaline water electrolysis. Here, we report a grafted superstructure, MOF@POM, formed by self-assembling a metal-organic framework (MOF) with polyoxometalate (POM). In situ electrochemical transformation converts MOF into active metal (oxy)hydroxides to produce a catalyst with a low overpotential of 178 millivolts at 10 milliamperes per square centimeter in alkaline electrolyte. An anion exchange membrane water electrolyzer incorporating this catalyst achieves 3 amperes per square centimeter at 1.78 volts at 80°C and stable operation at 2 amperes per square centimeter for 5140 hours at room temperature. In situ electrochemical spectroscopy and theoretical studies reveal that the synergistic interactions between metal atoms create a fast electron-transfer channel from catalytic iron and cobalt sites, nickel, and tungsten in the polyoxometalate to the electrode, stabilizing the metal sites and preventing dissolution.

Proton exchange membrane water electrolyzer (PEMWE) is considered to be a promising green hydrogen production technology but place high demand on the anodic oxygen‐evolving electrocatalysts to withstand the strong oxidizing and acidic reaction condition. Here we report a robust W ₁₈ O ₄₉ nanowire supported IrO _X (IrO _X ‐W ₁₈ O ₄₉ ) catalyst for acidic oxygen evolution reaction (OER) prepared by chemical vapor deposition followed with polyol reduction. The catalyst exhibits excellent electrocatalytic OER performance with an overpotential of 223 mV for a current density of 10 mA cm ⁻² and a small Tafel slope of 66.4 mV dec ⁻¹ in acidic media, superior to most electrocatalysts. More impressively, the assembled three‐electrode cell with IrO _X ‐W ₁₈ O ₄₉ as the working electrode exhibits excellent electrocatalytic OER performance and can operate stably at 10 mA cm ⁻² for 140 h. In‐situ spectroscopy characterizations reveal that the IrO _X ‐W ₁₈ O ₄₉ works in a route of lattice oxygen mechanism during OER. The favorable interaction between W ₁₈ O ₄₉ nanowires and the IrO _X active species together with the strong Ir−O interaction stabilizes the high‐valence Ir and prolongs the service life of the catalyst for OER.

A low Ir loading electrode of Ir–TiO ₂ /TP with efficient acidic OER activity.