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.

Supported noble metal cluster catalysts are typically operated under severe conditions involving switching between reducing and oxidizing atmospheres, causing irreversible transformation of the catalyst structure and thereby leading to permanent deactivation. We discovered that various platinum (Pt) precursors spontaneously disperse in a germanium-MFI (Ge-MFI) zeolite, which opposes the Ostwald ripening phenomenon, producing self-regenerating Pt/Ge-MFI catalysts for propane dehydrogenation. These catalysts reversibly switch between Pt clusters and Pt single atoms in response to reducing reaction and oxidizing regeneration conditions. This environmental adaptability allows them to completely self-regenerate over 110 reaction and regeneration cycles in propane dehydrogenation, and they exhibited unprecedented sintering resistance when exposed to air at 800°C for 10 days. Such spontaneous metal dispersion in a Ge-MFI zeolite is a robust and versatile methodology for fabricating various rhodium, ruthenium, iridium, and palladium cluster catalysts.

Advancements in proton-exchange membrane water electrolyzer depend on developing oxygen evolution reaction electrocatalysts that synergize high activity with stability. Here, we introduce an approach aimed at elevating oxygen evolution reaction performance by enhancing the spatiotemporal coordination of oxygen radicals to promote efficient O-O coupling. A dense, single-atom configuration of oxygen radical donors within interconnected RuO₂ nanocrystal framework is demonstrated. The stable oxygen radicals on gallium sites with adaptable Ga-O bonds are thermodynamically favorable to attract those from Ru sites, addressing dynamic adaptation challenges and boosting O-O coupling efficiency. The optimized catalyst achieves a low overpotential of 188 mV at 10 mA cm^-2, operates robustly for 800 h at 100 mA cm^-2 in acidic conditions, and shows a large current density of 3 A cm^-2 at 1.788 V, with stable performance at 0.5 A cm^-2 for 200 h, confirming its long-term viability in proton-exchange membrane water electrolyzer applications.

The efficient electrochemical CO₂ reduction to C₂₊ products at high current densities remains a significant challenge. Here we show inherently hydrophobic and hierarchically porous Cu supraparticles comprising sub-10 nm Cu constituent particles for ampere-level CO₂-to-C₂₊ electrosynthesis. These supraparticles feature abundant grain boundaries for high C₂₊ selectivity, coupled with interconnected mesopores and interparticle macropore cavities to enhance the accessibility of the active sites and mass transfer, breaking the trade-off between activity and mass transfer in Cu-based catalysts. Moreover, the intrinsic hydrophobicity of the supraparticles mitigates the water-flooding issue of catalytic layer in flow cells, improving the stability at high current densities. Consequently, the Cu supraparticles achieve ampere-level CO₂ electrolysis up to 3.2 A cm^-2 with a C₂₊ Faradaic efficiency of 74.9% (compared to 1.21 A cm^-2 and 55.4% for Cu nanoparticles) and maintain stability at 1 A cm^-2 for over 100 h. This work provides profound insights into the effect of the coupling of mass transfer and catalytic reaction under a high current and presents a corresponding solution by superstructure design.