Xiao Feng

The insufficient stability of transition metal nitrogen‐doped carbon (TM‐N‐C) catalysts has hindered the widespread adoption of non‐precious‐metal proton‐exchange‐membrane fuel cells (PEMFCs). Herein, using Fe‐doped MET(Zn)‐derived materials as a versatile platform, we unravel the role of oxygen groups in Fe‐N‐C catalyst degradation while achieving substantially enhanced fuel cell performance. DFT results indicate that carbonyl (C═O) and epoxy (C─O─C) groups lower the energy barrier of the rate‐determining step in the carbon oxidation reaction (COR), strengthen intermediate *OOH adsorption, and thereby accelerate carbon support corrosion. Based on this, a hydrogen‐thermal reduction strategy was developed to construct the Fe _SA /NC‐H catalyst with low surface oxygen content. Experimental results demonstrate the outstanding activity and stability of the Fe _SA /NC‐H catalyst. In H ₂ ‐O ₂ PEMFCs, the catalyst achieves a peak power density ( P _max ) of 1.32 W cm ⁻² , which is 1.26 times that of the reference catalyst (1.05 W cm ⁻² ). After 30 000 accelerated stress tests, Fe _SA /NC‐H retains 77.3% of its initial P _max , 1.56 times that of Fe _SA /NC (49.5%). It also shows only 7.5% voltage decay during a 100 h open‐circuit voltage durability test.

The insufficient stability of transition metal nitrogen‐doped carbon (TM‐N‐C) catalysts has hindered the widespread adoption of non‐precious‐metal proton‐exchange‐membrane fuel cells (PEMFCs). Herein, using Fe‐doped MET(Zn)‐derived materials as a versatile platform, we unravel the role of oxygen groups in Fe‐N‐C catalyst degradation while achieving substantially enhanced fuel cell performance. DFT results indicate that carbonyl (C═O) and epoxy (C─O─C) groups lower the energy barrier of the rate‐determining step in the carbon oxidation reaction (COR), strengthen intermediate *OOH adsorption, and thereby accelerate carbon support corrosion. Based on this, a hydrogen‐thermal reduction strategy was developed to construct the Fe _SA /NC‐H catalyst with low surface oxygen content. Experimental results demonstrate the outstanding activity and stability of the Fe _SA /NC‐H catalyst. In H ₂ ‐O ₂ PEMFCs, the catalyst achieves a peak power density ( P _max ) of 1.32 W cm ⁻² , which is 1.26 times that of the reference catalyst (1.05 W cm ⁻² ). After 30 000 accelerated stress tests, Fe _SA /NC‐H retains 77.3% of its initial P _max , 1.56 times that of Fe _SA /NC (49.5%). It also shows only 7.5% voltage decay during a 100 h open‐circuit voltage durability test.

Designing oxygen evolution reaction (OER) catalysts that simultaneously achieve high activity and long-term stability remains a critical challenge for the development of alkaline anion exchange membrane water electrolyzers (AEMWEs). Here, we uncover a unique support protection mechanism in which lattice-confined ruthenium (Ru) single atoms offer robust protection for the spinel Co3O4 support, realizing outstanding stability in AEMWEs. Theoretical calculations and structural characterizations reveal that lattice confinement promotes the formation of robust Ru–O–Co bridges by simultaneously shortening the Co–O and Ru–O bond lengths, thereby suppressing Co dissolution and optimizing the electronic structure for efficient catalysis. Furthermore, in situ electrochemical analysis demonstrates that the lattice confinement of Ru atoms accelerates OER kinetics through facilitated proton-coupled electron transfer (PCET) steps and partially activated lattice oxygen. As a result, the RuLCA-Co3O4 dominated by the adsorbate evolution mechanism (AEM) exhibits a lower overpotential of 260 mV at 10 mA cm–2, which is lower than that of RuSCA-Co3O4 dominated by the lattice oxygen mechanism (LOM) pathway. Meanwhile, the lattice-confined RuLCA-Co3O4 exhibits nearly 9-fold lower Co dissolution compared to surface-coordinated RuSCA-Co3O4 after an accelerated durability test (ADT). Moreover, RuLCA-Co3O4 maintains an outstanding stability for over 1000 h in an AEMWE system with a low degradation rate of 88.1 μV h–1, outperforming RuSCA-Co3O4. This work establishes lattice confinement as an effective strategy to decouple activity-stability trade-offs in alkaline OER and provides a viable design principle for durable AEMWE anodes.

Limited proton conductivity within the catalyst layer induces severe ohmic polarizations and constrains power output at high hydrogen-to-electricity efficiencies in proton exchange membrane fuel cells. We demonstrate that proton transfer can be boosted by constructing Brønsted acid–Lewis base interfaces through integrating organic open frameworks with Nafion. These confined interfaces mediate low-barrier relay pathways, disrupt hydrogen bonding to expedite water network reorganization, facilitate consecutive proton transfer, and enrich protons locally. Compared with Nafion, the complexes exhibit an order-of-magnitude increase in proton self-diffusion coefficient, a 6.5-fold rise in proton conductivity, and a 55% reduction in activation energy. When integrated with commercial platinum on carbon, they deliver a fourfold increase in rated power output relative to the baseline, outperforming representative state-of-the-art membrane electrode assemblies with advanced catalysts under similar conditions.

Constructing functional materials on cell surfaces offers a promising strategy to enhance cellular robustness and functionality; however, most existing approaches rely on static shells that are incompatible with the dynamic nature of biological interfaces. This mismatch imposes an inherent trade-off between sustained protection and cellular proliferation. Inspired by natural membranes that integrate covalently structured functional units within dynamic, noncovalent matrices, we developed a hydrogen-bonding-mediated, growth-coupled assembly strategy to engineer adaptive porous membranes on living cells. Nanosized hydrogen-bonded organic framework (HOF) particles act as dynamic reservoirs of building units that, together with multivalent interfacial interactions, promote surface enrichment, reorganization, and crystallization into continuous membranes. This dynamic assembly mechanism accommodates cellular proliferation while maintaining structural integrity, cytoprotection, and selective molecular transport. Furthermore, the adaptive membranes impart photoactivity that couples with cellular metabolism, allowing light-driven cofactor regeneration and boosting triterpenoid betulinic acid production by 4.8-fold in engineered yeast while maintaining stress tolerance. This study establishes a design principle for integrating adaptive functional artificial membranes with living cells.

Conspectus: Biological membranes constitute the fundamental scaffolding of life, serving as sophisticated interfaces that drive cellular function through the spatial compartmentalization of functional units. They integrate enzymatic catalysis, molecular recognition, and regulated transport within finely tuned microenvironments, ensuring exceptional efficiency, selectivity, and resilience in biological conversion networks. Translating these advantages beyond native biological contexts remains a central objective in chemical manufacturing, biotechnology, and biomedicine. However, the inherent fragility of enzymes and living cells outside physiological environments, combined with the mismatch between the survival-oriented nature of biological systems and the performance-driven requirements of industrial manufacturing, hinders their broader application. Therefore, bridging the biological sophistication with industrial rigor necessitates the development of programmable synthetic platforms capable of re-encoding these membrane-inspired principles into robust and functional material architectures. Covalent organic frameworks (COFs), featuring long-range-ordered structures, finely tunable nanochannels, high porosity, and chemically tailorable frameworks, offer a compelling platform to address this challenge. Their molecular-level programmability enables precise control over pore sizes and interfacial chemistry, allowing for the construction of confined microenvironments commensurate with biomacromolecules. Beyond serving as immobilization supports, the structural precision of COFs enables function-driven biomimetic engineering. Deeper investigations into biointegration strategies and membrane-mimetic design within COFs are essential for advancing next-generation catalytic, energy, and biomedical materials. In this Account, we summarize our group’s efforts to bridge biological function with COF design along two complementary directions. First, we develop COF-based biointegrated confined microreactors that engineer membrane-inspired catalytic environments for enzymes and living cells. By tailoring confinement dimensions, engineering hydration-like microenvironments, and modulating covalent anchoring interactions, COFs create protective yet tunable nanoscale compartments that stabilize biomacromolecules and optimize their conformations. The assembly of selective transport channels at biointerfaces further enables efficient substrate exchange while excluding detrimental species, extending biocatalysis into harsh or non-native environments. Importantly, these confined architectures further support functional expansion toward continuous-flow operation, multienzyme, and chemoenzymatic cascade systems, transforming isolated biological components into versatile, integrated catalytic platforms. Second, moving beyond biointegration, we demonstrate that COFs can be designed to emulate core structural and functional attributes of biological membranes. Through hydrophilicity-gradient nanochannels, adaptive linkage chemistries, and spatially defined binding pockets, COFs can encode directional transport, hydration regulation, and selective molecular recognition directly into crystalline porous frameworks. Finally, we discuss current challenges and outline future opportunities toward intelligent, adaptive biomimetic architectures. It is expected that this Account would provide an understanding of structure–function relationships in membrane-inspired COF engineering and inspire the development of next-generation biointerfaces for catalysis, energy conversion, environmental remediation, and biomedical technologies.

Polyamide membranes are essential for lithium extraction from salt-lake brines, yet optimizing their ion-sieving efficiency remains difficult. Herein, we report an ultrathin polyamide membrane (∼10 nm thick) with a low surface roughness (R_a = 1.18 nm) and an engineered asymmetric charge distribution. The membrane combines a positively charged upper layer, a negatively charged lower layer, and an interfacial region with narrower pores formed via interlayer interpenetration. This architecture promotes differential dehydration of Mg²⁺ and Li⁺ at the upper layer and amplifies selectivity through the interfacial region. Passage through the positive layer increases ion charge exposure, enhancing diffusion selectivity within the negatively charged interior and raising the transmembrane energy barrier for Mg²⁺ relative to Li⁺. The membrane achieves a Li⁺/Mg²⁺ selectivity of 69 and a water permeation flux of 12 L m^-2 h^-1 bar^-1, surpassing commercial benchmarks. Its ultrasmooth surface and high hydrophilicity minimize fouling, maintaining a flux recovery above 90% under high contaminant loads. Scaled-up modules using a three-stage nanofiltration process reduced the Mg²⁺/Li⁺ ratio in a concentrated brine simulant (25 g L^-1) from 50 to 0.2, highlighting strong potential for industrial lithium recovery.

A TPB-centered framework reveals how coupled oxygen, proton, and water transport, together with ionomer-induced interfacial effects, govern PEMFC cathode performance.

In proton exchange membrane fuel cells (PEMFCs), ionomers in the catalyst layer tend to align lamellar to the catalyst surface, impeding the formation of continuous ionic domains essential for efficient proton transport. This alignment also obstructs oxygen diffusion to the catalyst‐liquid‐gas three‐phase boundary (TPB), which critically limits the PEMFC's power density. Here, we introduce porous graphene‐based nanosheet@Nafion composite ionomers that reconfigure ion transport domains and gas channels at the nanoscale within the catalyst layer. These composite ionomers dramatically enhance proton transport (5.0‐fold) and oxygen diffusion (3.3‐fold), increasing rated power density by 1.70 times and peak power density by 1.48 times compared to Nafion‐based fuel cells. Furthermore, they demonstrate significant durability improvements during accelerated stress tests. This strategy provides an effective approach to optimizing microstructures and constructing efficient multi‐species transport pathways at the TPB, highlighting their potential for maximizing the performance of advanced high‐activity electrocatalytic materials in PEMFCs.

In proton exchange membrane fuel cells (PEMFCs), ionomers in the catalyst layer tend to align lamellar to the catalyst surface, impeding the formation of continuous ionic domains essential for efficient proton transport. This alignment also obstructs oxygen diffusion to the catalyst‐liquid‐gas three‐phase boundary (TPB), which critically limits the PEMFC's power density. Here, we introduce porous graphene‐based nanosheet@Nafion composite ionomers that reconfigure ion transport domains and gas channels at the nanoscale within the catalyst layer. These composite ionomers dramatically enhance proton transport (5.0‐fold) and oxygen diffusion (3.3‐fold), increasing rated power density by 1.70 times and peak power density by 1.48 times compared to Nafion‐based fuel cells. Furthermore, they demonstrate significant durability improvements during accelerated stress tests. This strategy provides an effective approach to optimizing microstructures and constructing efficient multi‐species transport pathways at the TPB, highlighting their potential for maximizing the performance of advanced high‐activity electrocatalytic materials in PEMFCs.