N Nature Chemical Engineering · Dec 03, 2025 Selective partitioning and uphill transport enable effective Li/Mg ion separation by negatively charged membranes Efficient separation of lithium (Li+) and magnesium (Mg2+) is critical for enhancing sustainable lithium extraction from natural brines, which is vital for battery production and renewable energy technologies. Here we present a method for highly selective Li+/Mg2+separation driven by concentration gradients across negatively charged membranes with high charge densities. In contrast to typical electric field-driven transport in negatively charged membranes, where divalent cations generally permeate faster than monovalent cations, Li+ions in our system permeate the membrane at substantially higher rates than Mg2+ions. This unexpected selectivity stems from the selective ion partitioning properties of the membrane and the uphill transport of Mg2+ions against their external concentration gradient. We demonstrate the efficacy of this separation approach through bench-scale dialysis experiments using a model Atacama brine solution, achieving efficient separation of monovalent and divalent cations. The high separation efficiency observed in this study suggests a promising approach for monovalent/divalent ion separations, offering higher selectivity compared to current technologies. Chemical engineering Polymers
N Nature Chemical Engineering · Nov 27, 2025 Passive direct air capture via evaporative carbonate crystallization Direct air capture of CO2is needed to mitigate past emissions and those of persistent and difficult-to-abate sources. Current liquid-sorbent-based direct air capture relies on large-scale air handling and coupled sorbent–solid chemical loops, but the complexity and cost of this approach are barriers to scaling. Here we report a departure from established capture mechanisms in which ultraconcentrated KOH solutions (>9 M) achieve rapid CO2-to-carbonate crystallization at the air interface. On the basis of this finding, we develop a carbonate crystallizer that leverages evaporation to concentrate KOH on a wicking substrate, enabling the stable, passive capture of atmospheric CO2directly into a solid form. This approach achieves a capture flux over sixfold that of conventional systems, with regeneration demonstrated via a subsequent electrochemical step. A module with 100 such crystallizers achieved an average capture flux over threefold that of conventional contactors, with sustained operation over seven cycles and 25 days. This passive, single-chemical-loop approach has the potential to reduce capital and levelized costs by approximately 42% and 32%, respectively, compared with conventional liquid-based direct air capture systems. Carbon capture and storage Chemical engineering
N Nature Chemical Engineering · Nov 19, 2025 An industrial automated laboratory for programmable protein evolution Current methods for protein engineering are constrained by limited understanding of sequence–function relationships, the difficulty of designing complex properties by artificial intelligence methods and labor-intensive directed evolution. Here, to enable continuous and scalable protein evolution and systematic exploration of protein adaptive landscapes, we established an industrial-grade automation platform featuring high throughput, high efficiency, enhanced reliability and minimal human intervention (operational for ~1 month). We then developed new genetic circuits for the OrthoRep continuous evolution system to achieve growth-coupled evolution for proteins with diverse and complex functionalities. This included improving lactate sensitivity of LldR via dual selection and increasing operator selectivity for LmrA using the NIMPLY circuit. We integrated these components into an all-in-one laboratory, iAutoEvoLab, and evolved proteins from inactive precursors to fully functional entities, such as a T7 RNA polymerase fusion protein CapT7 with mRNA capping properties, which can be directly applied to in vitro mRNA transcription and mammalian systems. Our system represents a versatile tool for protein engineering and expands the scope for investigating the origins and evolutionary trajectories of protein functions. Biomedical engineering Biotechnology Proteins
N Nature Chemical Engineering · Nov 17, 2025 Water dissociation efficiencies control the viability of reverse-bias bipolar membranes for CO2electrolysis Bipolar membranes operated under reverse-bias (r-BPM) provide the only potential route to use anodes free of platinum group metals in CO2electrolyzers when paired with the oxygen evolution reaction. Under 100% water dissociation efficiency (WDE) conditions, the OH−generated by a r-BPM fully replenishes the OH−consumed by the oxygen evolution reaction, maintaining an alkaline anolyte. However, unwanted co-ion crossover leads to <100% WDEs, gradually causing anolyte acidification and nickel-based anodes to corrode over time. Here we experimentally measured the WDE of r-BPMs in a membrane–electrode assembly configuration as a function of the current density, anolyte concentration and cation identity, finding that the highest measured WDE of 98% is insufficient to maintain an alkaline environment over extended operation. We further highlight through modeling that WDEs >99.8% are required to operate for >10,000 h with reasonable anolyte volumes. Our results show that r-BPMs CO2electrolyzers require additional strategies, such as reverting to platinum group metal anodes or regenerating the anolyte, to operate stably at an industrial scale. Chemical engineering Electrocatalysis
N Nature Chemical Engineering · Oct 21, 2025 Ultrafast ammonia decomposition using an electrified tungsten wire lightbulb reactor Ammonia decomposition is a key reaction in the green hydrogen economy because ammonia is an important carbon-free hydrogen carrier. In contrast to the prevalent focus on developing active catalysts to address the reaction’s slow kinetics at low temperatures, we introduce a tungsten wire lightbulb reactor that operates at unconventionally locally high temperatures while maintaining enhanced efficiency. Near the wire, the local temperature reaches up to 1,800 K, enabling ultrafast ammonia decomposition with rate constants much higher than those of leading catalysts under typical reaction conditions. Concurrently, the sharp temperature decrease along the radial direction allows for low power input, thus enhancing energy efficiency. The lightbulb reactor also realized up to 99.995% conversion at enhanced power input without the use of additional separation steps. We further propose a scaled-up reactor design that is two to three orders of magnitude smaller than current state-of-the-art reactors and highlight its potential applications within the emerging hydrogen economy. Chemical engineering Hydrogen energy
N Nature Chemical Engineering · Oct 14, 2025 Closed-loop recycling of polyethylene to ethylene and propylene via a kinetic decoupling–recoupling strategy Conversion of polyethylene (PE) into ethylene and propylene will enable closed-loop recycling of plastics. Conventional catalytic cracking of PE is restricted by kinetic entanglement between the formation of main products and by-products, limiting ethylene and propylene yields to less than 25%. Here we address this challenge with a kinetic decoupling–recoupling (KDRC) strategy, achieving yields of ethylene and propylene up to 79% from PE conversion using a tandem reactor with dual zeolite catalysts. Reaction kinetics analysis, synchrotron-based vacuum ultraviolet photoionization mass spectrometry and in situ neutron powder diffraction reveal that KDRC decouples kinetics of PE cracking to intermediates (butenes and pentenes) in the first stage and synchronizes this process with dimerization–β-scission reactions in the second stage. This synchronization minimizes by-products and enhances ethylene and propylene production substantially. Combined with high catalytic stability, this KDRC strategy represents a robust pathway to combating plastic pollution via a circular economy. Catalysis Chemical engineering
N Nature Chemical Engineering · Oct 07, 2025 Growing functional artificial cytoskeletons in the viscoelastic confinement of DNA synthetic cells Intracellular structures, such as cytoskeletons, form within a crowded cytoplasm with viscoelastic properties. While self-assembly in crowding is well studied, the effects of coupled viscoelastic environments remain elusive. Here we engineer all-DNA synthetic cells (SCs) with tunable viscoelastic interiors to investigate this phenomenon. We introduce facile DNA barcode engineering to selectively enrich DNA tiles with adjustable concentrations into SCs to form artificial cytoskeletons coupled to their interior. Distinct mechanistic differences in assembly occur compared with solution or simple crowding. Furthermore, we develop light, molecular and metabolic switches to direct structure formation and create self-sorted SC populations with distinct artificial cytoskeletons. These cytoskeletons strengthen SCs and support stable contacts with mammalian cells. By bridging molecular-scale DNA nanotube assembly with mesoscale condensate structures, our SCs provide a versatile platform to investigate self-assembly under viscoelastic confinement and to harness subcellular architectures for emerging applications. Engineering structurally and functionally complex synthetic cells remains a key challenge. Here DNA condensate synthetic cells combine phase separation and DNA nanostructures to reveal how switchable artificial cytoskeletons assemble in viscoelastic confinements. These cytoskeletons improve the mechanical properties of synthetic cells and enable stable mechano-interfaces with mammalian cells. Bioinspired materials DNA nanotechnology Self-assembly Soft materials
N Nature Chemical Engineering · Oct 03, 2025 Interpretable machine learning-guided plasma catalysis for hydrogen production Low-carbon ammonia decomposition via nonthermal plasma is a promising method for on-site hydrogen production, but finding optimal catalysts is challenging. Here we use multiscale simulations to link catalytic activity to nitrogen adsorption energy (EN) and identify the best catalysts for conventional heating and nonthermal plasma: Ru and Co, respectively. With an idealENof −0.51 eV for plasma catalysis, we applied machine learning to screen 3,300+ catalysts and designed efficient, earth-abundant alloys such as Fe3Cu, Ni3Mo, Ni7Cu and Fe15Ni. Plasma catalytic experiments at 400 °C further validated that the above alloys achieved higher conversions than the individual metals, and they also have comparable performance to Co. Our techno-economic analysis demonstrated potential economic benefits of plasma catalytic ammonia decomposition over Ni3Mo, highlighting a H2production cost below the US$1 per kg H2target and a low carbon footprint of ~0.91 kg of CO2per kg H2. Catalytic mechanisms Chemical engineering Computational methods Computational science Hydrogen storage
N Nature Chemical Engineering · Sep 11, 2025 Spin-on deposition of amorphous zeolitic imidazolate framework films for lithography applications Amorphous zeolitic imidazolate framework (aZIF) films have been recently introduced as resists for electron beam and extreme ultraviolet lithography. aZIFs are also being considered for separation applications, including thin film membranes. However, the reported methods for aZIF deposition are currently based on highly empirical trial-and-error approaches that hinder control of film composition, thickness and uniformity as well as scale-up and transferability to different coating geometries. This work presents a method for depositing aZIF films with controllable thickness using dilute precursors mixed immediately before encountering the substrate. Importantly, the method is amenable to quantitative analysis by computational fluid dynamics to extract intrinsic deposition rates and limiting reactant transport diffusivities, enabling predictive physics-based modeling of the deposition process. This allows the deposition method to be adapted for spin coating on silicon wafers to prepare high-quality aZIF films with consistently controlled thickness. Using this approach, high-resolution resist performance and wafer-scale use for beyond extreme-ultraviolet lithography of aZIF films is demonstrated. Chemical engineering
N Nature Chemical Engineering · Sep 11, 2025 Rapid solid-phase synthesis of highly crystalline covalent organic framework platelets Covalent organic frameworks (COFs) have demonstrated superior performance in wide-ranging applications, yet their practical deployment has been long hindered by their inconvenient synthesis protocols. Toxic solvents, tedious procedures and long reaction times are typically involved in their synthesis, and microcrystalline powders are commonly obtained, which are unfavorable in practical use. Unfortunately, newly developed methods aiming to resolve these challenges often lead to deteriorated COF crystallinity and porosity. Here we develop a solid-phase hot-pressing method to fabricate 15 types of highly crystalline COF platelet of various linkage types, including imine-, hydrazone-, β-ketoenamine- and imide-linked COFs. Moreover, COF platelets with complex chemical structures, including a COF with three-dimensional geometry and a COF with multiple monomer components, have been successfully obtained. In particular, all COF platelets can be obtained within a short processing time of 0.5–5 min, with high crystallinity and porosity. Finally, as a proof-of-concept application, a β-ketoenamine-linked COF platelet is directly assembled into an atmospheric water harvesting device, demonstrating excellent water collecting performance. Chemical engineering Materials chemistry
N Nature Chemical Engineering · Sep 08, 2025 Closed-loop recycling of mixed polyesters via catalytic methanolysis and monomer separations A sustainable plastics future will require high recycling rates and the use of biogenic feedstocks, which together are catalyzing interest in replacing fossil fuel-derived, noncircular polyolefin packaging materials with bio-based, chemically recyclable polyesters. Here we present a catalytic methanolysis process capable of depolymerizing both fossil fuel- and bio-based polyesters, including polyethylene terephthalate (PET), polylactic acid, polybutylene adipate terephthalate and polybutylene succinate in one reactor under mild conditions with high monomer yields. We scaled this process to 1 kg and integrated separations engineering using activated carbon, crystallization, extraction and distillation to remove contaminants and recover individual monomers from depolymerized mixed polyesters with high yield and purity. PET synthesized from monomers isolated from postconsumer materials showed comparable mechanical and thermal properties to PET from commercial monomers. Techno-economic analysis and life cycle assessment show that this process is economically viable and exhibits lower environmental impacts than primary production of respective polymers. Biopolymers Catalysis Chemical engineering Polymers
N Nature Chemical Engineering · Aug 20, 2025 Boundary-sensing mechanism in branched microtubule networks The self-organization of cytoskeletal biopolymers, such as microtubules (MTs), depends on mechanosensing and adaptation to confined spaces such as cellular protrusions. Understanding how these active biopolymers coordinate their formation under confinement leads to advances in bioengineering. Here we report the self-organization of branched MT networks in channels with narrow junctions and closed ends, mimicking cellular protrusions. We find that branching MT nucleation occurs in the post-narrowing region only if this region exceeds a minimum length, determined by MT dynamic instability at the closed end and the timescale for nucleation at a distant point. We term this feedback ‘boundary sensing’. Increasing the amount of branching factor TPX2 in the system accelerates MT nucleation and adjusts this minimum length, but excess TPX2 stabilizes MTs at the closed end, disrupting network formation. We performed experiments and simulations to study how this tunable feedback, wherein growing MTs navigate confinement and create nucleation sites, shapes MT architecture. Our findings impact the understanding of MT self-organization during axonal growth, dendrite formation, plant development, fungal guidance and the engineering of biomaterials. Biological physics Mechanical engineering Molecular self-assembly Polymers Proteins
N Nature Chemical Engineering · Aug 19, 2025 Scalable metal–organic framework-based electrodes for efficient alkaline water electrolysis Renewable electricity-driven water splitting is essential for decarbonizing high-emission industries and transportation. Metal–organic frameworks (MOFs) have shown great promise as catalytic materials for water splitting, but substantial gaps remain between fundamental research and practical application. Here we report the scalable and rapid synthesis of CoCe MOFs for alkaline water-splitting electrolyzers, achieving low energy consumption (4.11 kWh Nm−3H2) and long-term stability (5,000 h). Experiments indicate that the advantageous physiochemical properties of CoCe MOFs such as lattice distortion and large specific surface area enhance catalytic activity, facilitate water and gas transport and improve electrolyte accessibility to catalytic interfaces in practical devices. Preliminary techno-economic analysis shows that the cost of hydrogen produced from the CoCe MOF-based electrolyzer is US$2.71 kg−1, which is close to the target cost set by the US Department of Energy, and a life cycle assessment indicates that green hydrogen has up to 84.5% lower life cycle carbon emissions than traditional gray hydrogen production pathways. Chemical engineering Hydrogen energy
N Nature Chemical Engineering · Aug 15, 2025 Hydrogen evolution and dynamics in hydrogel electrochemical cells for ischemia–reperfusion therapy Molecular hydrogen (H2) protects organs from reactive oxygen species damage associated with ischemia–reperfusion (I/R) injury. Existing H2delivery methods, such as gas inhalation and H2-rich water consumption, target the entire body and experience leakage during administration. Here we engineer a portable hydrogel electrochemical cell that enables on-demand H2production via the hydrogen evolution reaction. The system enables H2controlled generation, localized storage and sustained diffusion to the tissue–device interface, with better controllability and sustainability. We conduct a thorough study of H2evolution and dynamics in the hydrogel system, evaluating the influence of hydrogel polymer composition on the hydrogen evolution reaction kinetics, bubble morphologies and storage. We validate its protective effects (1) in vitro with cardiomyocytes and keratinocytes, (2) ex vivo in I/R hearts and (3) in vivo in skin I/R pressure ulcers. These findings demonstrate the potential of the hydrogel electrochemical cell design for efficient and sustainable H2delivery in I/R therapy, which could be broadly applied in other gas-based therapies and drug delivery research. Biomedical engineering Chemical engineering Energy science and technology Mechanical engineering
