To overcome the limited visible-light absorption and scarce active sites of Bi2WO6, Nd-doped Bi2WO6 (4%Nd-BWO) was synthesised via a hydrothermal method. Nd doping induced lattice distortion, narrowed the bandgap, and increased surface roughness while maintaining a mesoporous structure. Consequently, through visible-light photocatalysis, 4%Nd-BWO achieved a 90.3% degradation rate for tetracycline, a 14% enhancement over pure Bi2WO6. Quenching experiment identified •O2− and h+ as the primary active species. This study demonstrates that defect engineering and lattice regulation effectively boost bismuth-based photocatalysts for antibiotic wastewater remediation.
NaSICON is referred to a family of crystalline structures with the common property of an easy migration of sodium ions inside the crystal channels, a peculiarity that allows these materials to be employed in solid-state cells as electrolytes or even electrodes. Here we report the results of the investigation of the sodium migration process by means of density functional theory calculations on models of the non-stoichiometric NaSICON material Na3.31Zr1.67(SiO4)1.84(PO4)1.16. The size of the supercell used in this work should soften the spurious effects of periodicity on the final results, i.e. the activation energies corresponding to the migration of the Image 1001 ion between two topologically distinct sodium sites. Different local environments were investigated to highlight the dependence both on type and presence of atomic nuclei in the channel, thus obtaining the activation barriers of the migration process in the presence of single or multiple local Image 1002 substitutions, and in the presence of a Image 1003 ion vacancy. Concurrently, a structural analysis of the NaSICON cavities mainly involved in the process was carried out. The results obtained shed light on the effects of the alterations of the NaSICON local composition on the Image 1004 migration that, other than having an intrinsic interest per se, can be used as a starting point for statistical simulations.
Two-dimensional systems have recently emerged as a vital frontier for exploring quantum phases. Within this context, this work investigates the monolayer silver dichloride AgCl2, revealing its intrinsic topological character through first-principles analysis. Its simple electronic structure gives rise to ideal Dirac nodal points. Symmetry analysis and edge-state spectroscopy confirm the topological origin and experimental accessibility. Besides, the mechanical anisotropy is characterized, and strain-induced modulations of topological structures are explored. With its demonstrated superior stability and intrinsic topological phase, the AgCl2 monolayer constitutes a compelling platform for advancing both fundamental understanding and technological applications in the rapidly evolving two-dimensional quantum materials.
In this letter, we present computational results on positron binding to glyoxal (C2H2O2). Results are reported using Hartree–Fock, configuration interaction, and diffusion Monte Carlo methods, the latter employing both single- and multi-configurational trial wavefunctions. We find that a positron binds to the cis isomer but not to the trans isomer. Our best estimate of the positron affinity for the cis isomer is 131 ± 22 meV. This is approximately seven times larger than the binding of an excess electron in the dipole field of cis-glyoxal.
In this study, carbon layer-protected FeS2@C-TiO2 heterojunction photocatalyst was synthesized via MIL-125 pyrolysis and subsequent in-situ growth of FeS2 nanoparticles. The optimized 1.5FST (where 1.5 represents the feeding molar ratio of Na2S to FeCl3) sample possesses hierarchical micro-mesoporous structure, a narrowed bandgap of 2.17 eV and strong visible-light absorption. The synergistic photocatalysis and PMS activation restrain charge recombination and accelerate Fe3+/Fe2+ redox cycling. The 1.5FST/PMS/Vis system achieves 94.66% TC degradation and 57.95% mineralization, exhibiting wide pH adaptability, anti-interference capacity and stable recyclability. Mechanism studies prove 1O2 and O2− are dominant species, and mung bean germination tests confirm efficient toxicity reduction.
