Activating the Basal Plane of 2H-MoS2 by Doping Phosphor for Enhancement in the Photocatalytic Degradation of Organic Contaminants

Enhancing the photocatalytic efficiency of two-dimensional aluminum nitride materials through strategic rare earth doping

Two-dimensional (2D) materials demonstrate promising potential as high-efficiency photocatalysts. However, the intrinsic limitations of aluminum nitride (AlN), such as inadequate oxidation capacity, a high carrier recombination rate, and limited absorption of visible light, pose considerable challenges. In this paper, we introduce a novel co-doping technique with dysprosium (Dy) and carbon (C) on a 2D AlN monolayer, aiming to enhance its photocatalytic properties. Our first-principles calculations reveal a reduction in the bandgap and a significant enhancement in the visible light absorption rate of the co-doped Al24N22DyC2 structure. Notably, the distribution of the highest occupied molecular orbital and the lowest unoccupied molecular in proximity to Dy atoms demonstrates favorable conditions for carrier separation. Theoretical assessments of the hydrogen evolution reaction and oxygen evolution reaction activities further corroborate the potential of Al24N22DyC2 as a competent catalyst for photocatalytic reactions. These findings provide valuable theoretical insights for the experimental design and fabrication of novel, high-efficiency AlN semiconductor photocatalysts.

Atomic-Scale Surface Engineering for Giant Thermal Transport Enhancement Across 2D/3D van der Waals Interfaces

Heat dissipation in two-dimensional (2D) material-based electronic devices is a critical issue for their applications. The bottleneck for this thermal issue is inefficient for heat removal across the van der Waals (vdW) interface between the 2D material and its supporting three-dimensional (3D) substrate. In this work, we demonstrate that an atomic-scale thin amorphous layer atop the substrate surface can remarkably enhance the interfacial thermal conductance (ITC) of the 2D-MoS₂/3D-GaN vdW interface by a factor of 4 compared to that of the untreated crystalline substrate surface. Meanwhile, the ITC can be broadly manipulated through adjusting substrate surface roughness. Phonon dynamic and heat flux spectrum analyses show that this giant enhancement is attributed to the increased phonon densities and channels at the interfaces and enhanced phonon coupling. The slight surface fluctuation in MoS₂ and the increased diffuse interfacial scattering facilitate energy transfer from MoS₂'s in-plane phonons to its out-of-plane phonons and then to the substrate. In addition, it is further found that the substrate and its surface topology can dramatically influence the thermal conductivity of MoS₂ due to the reduction of phonon relaxation time, especially for low-frequency acoustic phonons. This study elucidates the effects of the amorphous surface of the substrate on thermal transport across 2D/3D vdW interfaces and provides a new dimension to aid in the heat dissipation of 2D-based electronic devices via atomic-scale surface engineering.