Developing efficient and stable oxygen evolution reaction (OER) electrocatalysts that can work stably in acidic conditions is crucial for advancing proton-exchange membrane water electrolysers commercialization. Here, we prepared a heterostructure-based OER electrocatalyst by in-situ growing RuO₂ nanoparticles on metal-organic-framework-derived Co₃O₄ nanoaggregates that can operate stably in acidic electrolytes. The interface of RuO₂/Co₃O₄ heterostructure, as well as their effect on electronic structure, were examined by various advanced characterizations. The optimized RuO₂/Co₃O₄ electrocatalyst reveals an ultra-low overpotential of 206 and 320 mV at 10 and 100 mA·cm⁻², respectively. X-ray photoelectron spectroscopy, differential electrochemical mass spectroscopy measurements and theoretical calculations indicate that the as-constructed RuO₂/Co₃O₄ interfaces could reduce the metal-oxygen covalence and energy barriers of rate-determining step, thereby decreasing the participation of lattice oxygen and preventing excessive oxidation of Ru sites during OER. In practical PEMWE systems, RuO₂/Co₃O₄ achieves 1.63 V at 1 A·cm⁻², and maintains remarkable stability for over 500 h with a very small voltage degradation rate of 0.2 mV·h⁻¹. This study provides a promising avenue for developing cost-effective OER electrocatalysts with superior activity and stability for advanced energy conversion.

Metal halide perovskites (e.g., CsPbBr₃) have emerged as highly promising scintillator materials owing to their superior optoelectronic characteristics. However, their practical deployment is constrained by intrinsic structural instability and nonradiative recombination-induced energy loss. Herein, we show that Ni²⁺ doping constitutes a potent regulatory strategy for synergistically improving the scintillation performance and environmental robustness of CsPbBr₃ perovskite. Various characterizations combined with threotecial calculation indicate that the incorporation of Ni²⁺ dopants triggers lattice contraction, thereby enhancing the resistance to environmental perturbations. Ni-doping also passivates intrinsic defects and traps, leading to marked suppression of nonradiative recombination pathways. This synergy in as-prepared Ni-doped CsPbBr₃ leads to an 11-fold enhancement in photoluminescence intensity and a substantial increase in photoluminescence quantum yield from 56.0% to 93.7%. Notably, it delivers an exceptional light yield of 38428.5 photons MeV^-1, a low detection limit of 64.9 nGy_air s^-1, and superior radiation tolerance. Furthermore, a flexible scintillation screen containing Ni-doped CsPbBr₃ enables high-resolution X-ray imaging with a spatial resolution of 16.6 lp mm^-1, notably surpassing that of the majority of reported perovskite-based scintillators. This study provides profound insights into the pivotal role of metal doping into halide perovskites for enhancing environmental stability in radiation detection technologies.

Electrochemical nitrate reduction reaction (NO₃RR) emerges as a sustainable approach for converting residual nitrate pollutants into valuable ammonia under ambient conditions, offering a promising alternative to the energy-intensive Haber–Bosch process. Compared to single-metal-site electrocatalysts, dual-metal-site (DMS) electrocatalysts show synergistic effects between adjacent metal sites, effectively regulating the electronic state and enhancing the catalytic activity and selectivity for NO₃RR with multi-step proton and electron transfers. Further understanding on NO₃RR is of practical significance for design of efficient DMS electrocatalysts. This review aims to systematically investigate the recent advancement of DMS electrocatalysts for NO₃RR to ammonia synthesis, providing new understandings and insights into this catalytic process. The NO₃RR mechanism, artificial intelligence (AI)-driven DMS synthesis, DMS synthesis/characterization, and design of chemical reaction systems are categorized and discussed. DMS electrocatalysts for NO₃RR at the cathode can reduce the energy input for water oxidation, biomass oxidation reactions, and zinc-nitrate batteries, while simultaneously enhancing the yields of anode and cathode products. Finally, the remaining challenges and future perspectives for DMS electrocatalysts in NO₃RR are further discussed. This review provides in-depth guidance for rational design of dual-site electrocatalysts, facilitating practical and sustainable electrochemical processes in the near future.

Electrocatalytic synthesis of ammonia (NH₃) from nitrate (NO₃⁻) is an effective approach for reducing nitrate pollutants in the environment and a promising method for ammonia synthesis under mild conditions. However, current catalyst syntheses are costly, and their application in real wastewater remains underexplored. Herein, we prepared high-efficiency copper-based single-atom-nanoparticle synergistic sites on carbon felt (Cu_SA/NP@C) from copper-containing wastewater. Trace Cu²⁺ in wastewater enables efficient nitrate reduction reaction (NO₃RR), and the effect of different Cu²⁺ concentrations was also investigated. The optimized Cu_SA/NP@C, with synergy between single atoms and nanoparticles, shows excellent activity: a maximum Faradaic efficiency of ~ 100% (at −0.3 V vs. reversible hydrogen electrode (RHE)) and a NH₃ yield of ~ 10 mg·cm⁻². Theoretical calculations reveal that Cu single-atoms and nanoparticles synergistically act on the NO₃* and H* intermediates to promote nitrate hydrogenation to NH₃. A membrane electrode assembly with the Cu_SA/NP@C cathode achieves the NH₃ synthesis at an industrial current density of 200 mA·cm⁻² for over 90 h. This “treating waste with waste” strategy offers new paths for nitrate wastewater recycling and green NH₃ synthesis advancement.