Impact of Potassium Doping on a Two-Dimensional Kagome Organic Framework on Ag(111).

Alkali element doping has significant physical implications for two-dimensional materials, primarily by tuning the electronic structure and carrier concentration. It can enhance interface electronic interactions, providing opportunities for effective charge transfer at metal-organic interfaces. In this work, we investigated the effects of gradually increasing the level of K doping on the lattice structure and electronic properties of an organometallic coordinated Kagome lattice on a Ag(111) surface.

On-Surface Synthesis of Two-Dimensional Carbon-Based Networks via Hierarchical Ullmann Coupling Reactions.

The recent developed bottom-up on-surface synthesis offers unprecedent opportunities for the fabrication of two-dimensional (2D) carbon-based networks with atomic precision. Hierarchical coupling approach has been proposed as an efficient strategy for improving the corresponding reaction selectivity and quality of target structures. Herein, we report the synthesis of a nitrogen-doped carbon-based network on Ag(100) utilizing a hierarchical Ullmann coupling strategy.

Indoor air quality in subway microenvironments: Pollutant characteristics, adverse health impacts, and population inequity.

Rapidly increasing urbanization in recent decades has elevated the subway as the primary public transportation mode in metropolitan areas. Indoor air quality (IAQ) inside subways is an important factor that influences the health of commuters and subway workers. This review discusses the subway IAQ in different cities worldwide by comparing the sources and abundance of particulate matter (PM and PM) in these environments.

Recent progress in on-surface synthesis of nanoporous graphene materials.

Nanoporous graphene (NPG) materials are generated by removing internal degree-3 vertices from graphene and introducing nanopores with specific topological structures, which have been widely explored and exploited for applications in electronic devices, membranes, and energy storage. The inherent properties of NPGs, such as the band structures, field effect mobilities and topological properties, are crucially determined by the geometric structure of nanopores. On-surface synthesis is an emerging strategy to fabricate low-dimensional carbon nanostructures with atomic precision.

On-Surface Synthesis of Novel Kagome Lattices Coordinated via Four-Fold N-Ag Bonding.

The Kagome lattice structures based on metal-organic coordination have garnered widespread interest because of their topologically Dirac/flat bands and other exotic electronic structures. However, the experimental fabrication of large-area two-dimensional (2D) Kagome lattice structures of metal-organic frameworks (MOFs) via on-surface synthesis remains limited. Herein, we successfully construct two kinds of large-scale 2D Kagome-type lattices stabilized by 4-fold N-Ag coordination on the Ag(111) surface.

Synthesis of a Porous [14]Annulene Graphene Nanoribbon and a Porous [30]Annulene Graphene Nanosheet on Metal Surfaces.

The electrical and mechanical properties of graphene-based materials can be tuned by the introduction of nanopores, which are sensitively related to the size, morphology, density, and location of nanopores. The synthesis of low-dimensional graphene nanostructures containing well-defined nonplanar nanopores has been challenging due to the intrinsic steric hindrance. Herein, we report the selective synthesis of one-dimensional (1D) graphene nanoribbons (GNRs) containing periodic nonplanar [14]annulene pores on Ag(111) and two-dimensional (2D) porous graphene nanosheet containing periodic nonplanar [30]annulene pores on Au(111), starting from a same precursor.

Selective synthesis of Kagome nanoporous graphene on Ag(111) an organometallic template.

Kagome nanoporous graphenes (NPGs) are fascinating due to their exotic electronic and magnetic properties. The emerging on-surface synthesis (mostly on metal surfaces) provides a new opportunity to fabricate Kagome NPGs with atomic resolution. Previously the Kagome NPGs synthesized on surfaces were largely heteroatom-doped and suffer from morphological defects (evidently on metal surfaces).

Recent Progress in Emerging Two-Dimensional Transition Metal Carbides.

As a new member in two-dimensional materials family, transition metal carbides (TMCs) have many excellent properties, such as chemical stability, in-plane anisotropy, high conductivity and flexibility, and remarkable energy conversation efficiency, which predispose them for promising applications as transparent electrode, flexible electronics, broadband photodetectors and battery electrodes. However, up to now, their device applications are in the early stage, especially because their controllable synthesis is still a great challenge. This review systematically summarized the state-of-the-art research in this rapidly developing field with particular focus on structure, property, synthesis and applicability of TMCs.