Electrocatalytic nitrate reduction reaction (NO3−RR) is expected to sustainably produce green ammonia and treat nitrate-containing wastewater by renewable energy. NO3−RR involves a complex multi-step pathway starting from nitrate adsorption to subsequent hydrogenation reactions by active hydrogen (*H). However, the simultaneous optimization of NO3− adsorption and *H supply by present modulation strategies of supported metal catalyst is still challenging. Herein, we utilize the coordination effect to effectively modulate surface metal coverage of metal oxide support to balance NO3− adsorption and *H generation for boosting NO3−RR performance. Experimental and theoretical results reveal that the electron-deficient Cuδ+ of CoO with low surface Cu coverage (CuLC-CoO) shows strong adsorption towards NO3− and the exposed CoO support can disturb interfacial hydrogen bond network to promote H2O dissociation and *H generation for hydrogenation reduction of NO3−. Therefore, CuLC-CoO catalyst shows an attractive Faradaic efficiency of 98.0%, and a high NH3 yield rate of 170.3 mg h−1 cm−2 at an industrial-relevant current density over 2 A cm−2. Furthermore, the NO3−RR||HzOR coupling system is constructed by using CuLC-CoO as bifunctional catalyst to produce ammonia with low energy consumption of 8.5 kWh kgNH3−1 for 100 cycles, and the commercialization value of the NO3−RR||HzOR system is demonstrated by techno-economic analysis.
Conventional energy-absorbing materials dissipate energy primarily through irreversible mechanisms such as plastic deformation, which often makes them single-use. To achieve reusability, energy-absorbing architectures relying on snap-through buckling or friction have been explored, but they typically require finely tuned geometries and additional design complexity that adds dead weight and complicates manufacturing. Here we introduce elasticity-assisted self-healing engineered structures (EASEs), a class of 3D-printed hybrid polymers that combine high specific energy absorption (SEA) with strong recoverability of mechanical performance after severe damage. The material comprises self-healable glassy epoxy domains dispersed within a rubbery polyurethane acrylate matrix, formed via polymerization-induced phase separation in a dual-curing epoxy–acrylate resin. Under mechanical loading, the rubbery matrix transfers load to the glassy domains, which dissipate energy through damage; upon unloading, the matrix elasticity restores the original shape of the material, while the thermally activated Diels–Alder chemistry heals the fractured epoxy domains. Digital light processing 3D printing enables precise control over both the dispersed-domain microstructure and complex macroscale architecture while preserving this damage-and-heal mechanism. Homogeneous samples reach a SEA of 1.77 kJ kg⁻1 at 50% compressive strain, and architected lattices tolerate strains as high as 0.6 yet recover nearly their initial stiffness and SEA after thermal healing. This damage-and-heal paradigm establishes a route to lightweight, reusable energy-absorbing architectures.
Conductive hydrogels have emerged as promising materials for wearable and implantable bioelectronic interfaces because they combine tissue-like mechanical properties with efficient signal transduction. Among them, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has attracted significant attention owing to its dual ion–electron conductivity, biocompatibility, and solution processability. However, practical bioelectronic applications require hydrogel electrodes to simultaneously achieve high conductivity, mechanical robustness, strong adhesion, self-healing capability, environmental and physiological stability, biocompatibility, and long-term conformal contact with biological tissues. Despite substantial progress in PEDOT:PSS hydrogels, a comprehensive understanding of how material structure and engineering strategies govern these functional requirements still remains elusive. This review systematically discusses the fundamental requirements for PEDOT:PSS hydrogels to function as high-performance hydrogel electrodes, as well as the corresponding material design strategies with trade-offs. Current challenges and future opportunities, including robust soft-to-rigid interconnections, asymmetric adhesion, transparent biointerfaces, machine learning-assisted systems, and multimodal decoupling strategies, are highlighted. Overall, this review provides a comprehensive design roadmap for developing next-generation PEDOT:PSS hydrogel bioelectronic interfaces.
MAX phases are layered ternary compounds (Mn+1AXn, n = 1–6) that combine metallic and ceramic characteristics, which arise from their alternating edge-sharing covalent [M6X] octahedra and A-element sublayers. Incorporation of lanthanides with strongly localized 4f electrons at the M site provides a promising route to introduce emergent properties. However, conventional synthesis strategies, including direct solid-state reactions, A-site substitution and X-site editing, are frequently constrained by competing phase formation or reliance on suitable MAX precursors. Here, we develop a Ln2A-derived strategy (Ln = Gd, Er, Lu; A = S, Se) to synthesize lanthanide MAX phases (Ln2AC) via a carbon intercalation-induced structural transformation. The resulting Ln2AC crystallize in the space group R-3 m. These compounds exhibit distinct thermal properties, with ratios of c- to a-axis thermal expansion coefficients ranging from 0.85 to 1.03, and thermal conductivities ranging from 6.550 to 11.712 W/(m·K). Furthermore, elements with unpaired 4f electrons (Ln = Gd, Er) endow Ln2AC with ferromagnetic behavior, as evidenced by Curie-Weiss temperatures ranging from 0.6 to 202 K and the presence of low-temperature ferromagnetic hysteresis at 2 K. This work establishes a sublayer-derived paradigm that unlocks access to lanthanide MAX phases and opens a route toward the design of coupled thermal and magnetic functional layered materials.
