Heterostructured Monolayer MoS₂ Nanoparticles toward Water-Dispersible Catalysts

MoS2 is a 2D semiconductor where exfoliation to a single layer results in improved catalytic properties. However, its high surface energy can lead to extensive aggregation, resulting in degraded catalytic performance and stability. Combined with a lack of dispersibility in water, this represents a pitfall for catalysis in the aqueous phase. Herein, we present the use of nanoscopic layered silicates pillared with a cationic surfactant to template the growth of MoS2 in the interlayer space. This provides heterostructured layered nanoparticles ∼25 nm wide by 3–8 nm thick containing isolated MoS2 layers. The resulting nanohybrids retain the disc-like morphology and surface chemistry of the clays, providing good aqueous stability, while also providing access to the catalytic edge-sites of the MoS2 layer. In addition to significant enhancement of catalytic dye degradation, molecular aggregation on the highly charged clay interface is comparable to unmodified clays. These particles are ideal for studies of charge-transport properties in confined semiconductor layers, as well as hierarchical self-assembly into functional materials. This study paves the way to colloidal synthesis of nanoparticulate heterostructures with other functional layered materials, particularly where particle exfoliation, covalent modification, and aqueous stability are concerns

Achieving High-Temperature Stable Structural Color through Nanostructuring in Polymer-Derived Ceramics

Structural colors offer a myriad of advantages over conventional pigment-based colors, which often rely on toxic chemical substances that are prone to UV degradation. To take advantage of these benefits in demanding environments, there is growing interest in producing structural colors from ceramics. Polymer-derived ceramics (PDCs) emerge as a compelling choice, presenting two distinct advantages: their enhanced shape ability in their polymeric state associated with impressive temperature resistance once converted to ceramics. This study pioneers the fabrication of noniridescent structural colors from silicon oxycarbide (SiOC) PDC, enabled by the nanostructuring of an inverse photonic glass within the PDC material. This design, a functionally graded material with an inverse photonic glass (FGM-PhG) structure, leverages the innate light-absorbing properties of SiOC, yielding a vivid structural color that maintains its saturation even in white surroundings. This study elucidates the process–structure–properties relationship for the obtained structural colors by investigating each layer of the functionally graded material (FGM) in a stepwise coating deposition process. To further emphasize the exceptional processing flexibility of PDCs, the three-step process is later transferred to an additive manufacturing approach. Finally, the FGM-PhG structural colors are demonstrated to have remarkable thermal stability up to 1000 °C for 100 h, possibly making them the most thermally stable ceramic structural colors to date