Circumventing thermodynamic limitations in converting carbon dioxide into carbon nanotubes via tandem catalysis

August 3, 2026| Source: PNAS

Carbon nanotubes (CNTs) are important materials for electronics and structural composites, but their production still relies on hydrocarbon-based chemical vapor deposition, an energy-intensive and fossil-dependent process, limited by rapid catalyst deactivation. Using CO 2 as a carbon feedstock offers a sustainable route for CNT synthesis, yet direct CO 2 conversion to CNTs is thermodynamically unfavorable and existing CO 2 -to-carbon pathways mainly yield amorphous or weakly graphitized solids. Here, we demonstrate a tandem electrochemical–thermochemical (EC-TC) strategy that overcomes these limitations. CO 2 is first electrochemically reduced to a tunable mixture of C 2 H 4 and CO, which is directly fed into a thermochemical reactor and converted into CNTs with controllable morphology and high CNT-to-metal mass ratios (~200) over NiFe catalysts at 750 °C. In situ synchrotron-based characterization and density functional theory calculations reveal that CO dissociation and C 2 H 4 decomposition on NiFe alloys cooperatively promote CNT nucleation and sustained growth. This EC-TC strategy establishes a modular route for converting CO 2 into value-added carbon nanomaterials.

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Widespread plasma jets in the Martian magnetosheath revealed by dual-spacecraft observations.

Plasma jets in planetary magnetosheaths are transient, high dynamic pressure structures capable of strongly perturbing downstream magnetospheres and modulating solar wind energy transfer. Although recently identified at Mars, their formation mechanisms and global occurrence remain poorly constrained. Using dual-spacecraft observations from Mars Atmosphere and Volatile EvolutioN and Tianwen-1, we show that magnetosheath jets occur throughout the Martian magnetosheath, in striking contrast to Eart

EnvironmentNovember 3, 2026

Defining and measuring proximity to criticality based on univariate time series.

Diverse social, engineered, and biological systems are made up of multiple interacting dynamical components; to work properly, certain components must be carefully regulated so that their dynamics avoid instability. However, many desirable properties, like optimized computation and control, emerge close to the tipping point between stability and instability, i.e., near criticality. Claims that such dynamical systems operate near criticality have been controversial because it is difficult to asse

EnvironmentNovember 3, 2026

Orexin and pupillary modulation for hunger control.

Fasting-based interventions improve metabolic health and are also explored as adjuncts in other clinical settings, but hunger remains a barrier to adherence. Fasting activates AgRP/NPY neurons (ANs), a hunger-promoting population whose inhibition reduces eating in hungry animals. Here we identify hypocretin/orexin neurons (HONs), classically associated with arousal, as rapid suppressors of AN activity. HON ablation increased AN population activity, whereas HON optostimulation rapidly suppressed

EnvironmentNovember 3, 2026

Environmental RNA improves detection and surveillance of schistosomiasis transmission.

Environmental diagnosis of schistosomiasis, a disease affecting over 250 million people globally, remains challenging, thereby limiting efficient eradication efforts. Current methods, including environmental DNA (eDNA), cannot distinguish between infectious parasite life stages present in the environment. Here, we develop and validate an environmental RNA (eRNA) approach that enables detection and quantification of Schistosoma mansoni miracidia (infective to snails) and cercariae (infective to h

EnvironmentNovember 3, 2026

Mechanism of catalytic regulation by an allosteric hot spot in dihydrofolate reductase.

Allostery is central to catalysis and regulation, yet how distal perturbations control enzyme activity remains unresolved. Here we elucidate how a distal allosteric hot spot regulates catalysis in dihydrofolate reductase, a benchmark enzyme exhibiting latent allostery. We combine enhanced conformational sampling, reactive free-energy calculations of the chemical step, and perturbation-induced nonequilibrium molecular dynamics with evolutionary analysis and experimental kinetics to obtain a compr