Haiming Huang

The dissociative dynamics of H2 on Pd1/Ag(111) and Cu1/Ag(111) single-atom alloy (SAA) surfaces were systematically investigated via full-dimensional quantum dynamical calculations. Two high-fidelity machine learning potential energy surfaces were constructed with root-mean-square errors (RMSEs) below 5.0 meV. Density functional theory calculations revealed significantly reduced static barriers of 0.22 eV for Pd1/Ag(111) and 0.73 eV for Cu1/Ag(111), compared to 1.22 eV for pristine Ag(111). Both SAA surfaces exhibited dramatically higher dissociation probabilities than Ag(111). However, this enhancement demonstrated strong energy dependence, with enhancement factors decreasing from ∼1000 at 1.0 eV to about 1.1 at 2.0 eV, indicating diminished SAA effects at elevated energies. Site-specific analysis revealed that Pd/Cu dopants selectively enhanced reactivity at bridge and fcc sites while suppressing reactivity at the top-Ag site. Remarkably, the vibrational excitation, rotational alignment, and rotational excitation effects remained qualitatively consistent with those observed on Ag(111) and Au1/Ag(111). These results demonstrate that SAAs quantitatively tune reactivity through localized electronic modifications while preserving the fundamental dynamical characteristics of H2 dissociation.

Exploring switching strategies for intrinsically chiral plasmonic nanoparticles is crucial for unlocking their potential in the dynamic manipulation of light polarization states. Conjugated polymers, such as polyaniline (PANI), represent highly promising material candidates for this pursuit, owing to their combination of intrinsic structural flexibility, tunable optical characteristics, and multistimuli responsiveness. Herein, we demonstrate chiroptical switching on PANI-encapsulated chiral gold nanorods (cAuNRs) by controlling proton doping of PANI, and reveal that the morphology of PANI within the nanogaps of cAuNRs results in abnormal spectral shifting, which is in contrast with those in previous studies. Moreover, we elucidate that the near-infrared absorption of doped PANI reduces the chiroptical response intensity, leading to splitting in the circular dichroism spectra. Our study provides valuable insights into the interaction between conjugated polymers and chiral plasmonic nanoparticles, supporting potential applications in nanoscale chiroptical switches for on-chip devices.

The dissociative dynamics of molecular H2 on the Au1/Ag(111) single-atom alloy (SAA) surface was systematically investigated through full-dimensional quantum dynamical calculations. A neural network-derived potential energy surface with a 4.2 meV root-mean-square error was employed to ensure high-fidelity simulations. Density functional theory calculations identified a reduced static dissociation barrier of 1.08 eV for the SAA system, compared to the 1.22 and 1.25 eV values for pristine Ag(111) and Au(111) surfaces, respectively. Despite this energetic advantage, the six-dimensional quantum dynamical analysis revealed that the dissociation probabilities for H2 in the vibrational ground (v = 0) state exceeded those on Ag(111) only at kinetic energies below 1.33 eV. This reactivity suppression at elevated energies was attributed to the site-specific modulation induced by the Au dopant, which selectively enhanced reactivities at the top-Au, hcp, and fcc sites while inhibiting those at bridge and top-Ag sites. Furthermore, the vibrational excitation, rotational alignment, and rotational excitation effects were found to closely resemble those observed for H2 dissociation on pristine Ag(111), demonstrating that the fundamental dynamical characteristics of the reaction remain qualitatively preserved despite SAA modification. These findings provide critical insights into the interplay between local electronic structure modification and global reaction dynamics in SAA systems.

Graphyne-family monolayers exhibit increasing complexity of anisotropic Raman properties with more acetylene units. Wavelength-dependent non-polarized Raman spectra of graphyne-family materials are correlated with their light absorbance differences.

Dielectric polymer materials are capable of storing energy stably and are utilized in numerous fields such as modern electronic devices and power systems. Thus far, the unappealable discharged energy density of the current dielectric polymer film has mainly been caused by insufficient breakdown strength and lower discharged efficiency. Herein, multilayer dielectric films consisting of polyethersulfone (PESU) as the outer layer and poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) doped with Ni-MOF as the middle layer were constructed. The PESU layer could block charge injection and effectively disperse the electric field strength of the single-layer film; moreover, the PESU with multiple active sites facilitates restricting the motion of carriers. Consequently, an elevated breakdown strength of 824 MV m⁻¹ is exhibited in multilayer nanocomposites, which is 164.8% that of PESU films, concomitant with a surged efficiency of 87.3%, which is 24.9% higher than that of pure P(VDF-HFP), and a superior discharged energy density of 20.8 J cm⁻³ is achieved. The multilayer dielectric material provides a feasible example for fabricating energy storage devices with the coupling of ultrahigh breakdown strength and efficiency.

Flexible dielectric and electronic materials are widely employed in emerging fields. Dielectric energy storage technologies and materials are needed to simultaneously cope with stringent requirements, such as high-stability and compact-size energy storage. Nonetheless, many mainstream polymer dielectrics prematurely fail under the coupling of rising electric field strength and space charge accumulation. Herein, we constructed a one-dimensional core–shell heterogeneous filler (BiFeO₃@Al₂O₃) and added it to wide HOMO–LUMO gap cyanoethyl cellulose, achieving ultrahigh breakdown strength (∼801 MV m⁻¹) and dielectric constant (∼17.3), thus obtaining a substantial discharged energy density of ∼31.3 J cm⁻³, accompanied by stabilized cyclic charge/discharge of 10⁵. The superior energy storage performance is ascribed to the shell (Al₂O₃) having a higher work function, forming built-in electric fields with core (BiFeO₃), simultaneously decreasing the density of state and increasing the bandgap of nanofibers. This research provides an optimization technique for crafting advanced polymer dielectrics, catering to the evolving demands of modern energy storage applications.