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Theory-guided discovery of ion-exchanged poly(heptazine imide) photocatalysts using first-principles many-body perturbation theory
No full textPoly(heptazine imides) (PHI) show strong promise in photocatalysis, but limited control over electronic properties continues to constrain their full potential. We modulated PHI’s photocatalytic activity to overcome this limitation by incorporating mono-, di-, and trivalent metal cations into its framework. We employed calculations based on many-body perturbation theory─a highly accurate approach for electronic structure calculations─which provides improved accuracy in quasiparticle energy predictions compared to conventional density functional theory, particularly for band gaps and excitonic properties, to elucidate the underlying mechanisms. The coupling between exchanged metals and the resulting optoelectronic properties is often nontrivial: Pd, Pt, and Cu1+, for example, produce favorable band structures but show limited photocatalytic activity due to optically forbidden intra-atomic d–d transitions. Our analysis identified several metal-doped PHI systems with electronic structures well suited for hydrogen and oxygen evolution, CO2 reduction, and H2O2 production. Guided by these theoretical insights, we synthesized a subset of M-PHI materials (where M is either K, Na, Li, Ca, Mg, or Zn) predicted to enhance photocatalytic reactivity. Photocatalytic measurements confirm substantial increases in H2O2 generation rates─up to 4.5-fold higher than undoped PHI─for these candidates, underscoring the effectiveness of our design strategy. These findings offer molecular-level insights into tailoring M-PHI interactions, paving the way for next-generation photocatalysts
Bernoulli’s principle-mediated Cl<sub>2</sub> electrosynthesis
No full textExisting technologies for chlorine (Cl2) synthesis are generally suffered from low productivity or high production cost. Guided by Bernoulli’s principle, here we report an efficient yet cost-effective electrochemical system for Cl2 electrosynthesis, which is composed of anodic chlorine evolution reaction (CER) connected to gas chamber by triple-phase gas diffusion layer. The key is to modulate gas diffusion layer by Bernoulli’s principle, wherein the pressure difference at triple-phase boundary drives oriented Cl2 migration directly into gas chamber, thus preventing the crossover of anodic/cathodic products. By further joining with a pH-tolerant catalyst, a standalone prototype device is built for high-rate Cl2 production, operating at the Faradaic efficiencies of 96.3% ~ 87.6% in the current density range of 0.1 ~ 1.14 A cm−2, having superior Cl2 synthesis performance. Further technical-economic evaluations of our synthetic scheme demonstrate reduced Cl2 production cost, saving 6.75% (1.17 million dollar per year) as comparison to conventional chlor-alkali design. We expect these findings offer broader opportunities to develop industrially production processes for other chemical commodities
Simultaneous delayed fluorescence and phosphorescence in organic luminescent material employing multiple excited states
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Two lock-in amplifiers based 3ω technique: A practical guide for thermal conductivity experiments in bulk samples
No full textThe accurate determination of thermal conductivity κ(T) in bulk materials at room temperature and above is crucial for evaluating their compatibility for specific applications. The 3ω technique is an established methodology for studying the thermal conductivity of thin films, becoming particularly suitable in the case of bulk specimens for T ≳ 300 K, where standard stationary techniques require significant corrections for radiative losses. Although this method has been employed in several works, it remains not widely adopted because its implementation demands considerable sophistication, including experiment design, thin film deposition techniques, and choices of the geometry of the current/heat transducer, electronics, and analytical treatment of the signals. Based on a critical review of the technique's key technical aspects, this work provides practical support for a rapid and user-friendly implementation, from the design phase through to execution and analysis. We release a Python-based graphical user interface that supports a quantitative estimation of the investigated temperature profiles based on the geometrical parameters (width/length) of the deposited transducer (heater/thermometer metal line) before an experiment, guaranteeing an optimal design of the experimental conditions for each given material under scrutiny. © 2026 Author(s). Published under an exclusive license by AIP Publishing
New Estimate for the Cosmic Ray-Induced H2 Photodissociation Rate in the Interstellar Medium
No full textAcid-Catalyzed Synthesis of Si-Stereogenic Silanes
No full textThe importance of Si-stereogenic silanes has been recognized in many fields of chemical science. Consequently, numerous catalytic enantioselective methods for their synthesis have been developed. Despite these advances, such methods have traditionally relied on transition-metal catalysts, predominantly rhodium and palladium. Recently, Brønsted acid catalysts have emerged as powerful alternatives to transition-metal catalysts. In particular, imidodiphosphorimidate (IDPi) and chiral phosphoric acid (CPA) catalysts have enabled access to structurally diverse Si-stereogenic silanes, including silyl ethers, silacycles, and disiloxanes, that were not previously attainable. In this review, we describe the recent advances made in Brønsted acid catalysis for the synthesis of Si-stereogenic silanes. We also discuss the relevant background and reaction mechanisms. We hope that this review will suggest future research directions in this emerging area
Rapid formation of a very massive star (>50000 M⊙), and subsequently, of an IMBH, from runaway collisions Direct N-body and Monte Carlo simulations of dense star clusters
No full textContext. We present simulations of a massive young star cluster using the codes Nbody6++GPU and MOCCA. The cluster is initially more compact than previously published models. It contains one million stars and has a total mass of 5.86 x 10(5) M-circle dot and a half-mass radius of 0.1 pc. Aims. We analyzed the formation and growth of a very massive star (VMS) through successive stellar collisions and investigated the subsequent formation of an intermediate-mass black hole (IMBH) in the core of a dense star cluster. Methods. We used direct N-body and Monte Carlo simulations that incorporated updated stellar evolution prescriptions for single and binary stellar evolution (SSE and BSE) tailored to massive stars and VMSs. These include revised treatments of stellar radii, rejuvenation, and mass loss during collisions. While the prescriptions represent reasonable extrapolations into the VMS regime, the internal structure and thermal state of VMSs that formed through stellar collisions remain uncertain, and future work may require further refinement. Results. Runaway stellar collisions in the cluster core produce a VMS that exceeds 5 x 10(4) M-circle dot within 5 Myr that subsequently collapses into an IMBH. We stress that further work on stellar astrophysics is needed, particularly in the context of VMS formation. The VMS formation currently represents strong uncertainties. Conclusions. Our model suggests that dense stellar environments may enable the formation of VMSs and massive black hole seeds through runaway stellar collisions. These results provide a potential pathway for early black hole growth in star clusters and offer a theoretical context for interpreting recent observations with the James Webb Space Telescope of young compact clusters at high redshift