Considerable efforts have been devoted to enhancing the photocatalytic activity and solar energy utilization of photocatalysts. The fabrication of type II heterostructures plays an important role in photocatalysts modification and has been extensively studied. In this review, we briefly trace the application of type II heterostructured semiconductors in the area of environmental remediation and water splitting, summarize major fabrication methods, describe some of the progress and resulting achievements, and discuss the future prospects. The scope of this review covers a variety of type II heterostructures, focusing particularly on TiO2 and ZnO based visible light driven type II 0D and 1D heterostructured photocatalysts. Some other low dimensional nanomaterials which have shown high-performance photocatalysis are also presented. We expect this review to provide a guideline for readers to gain a clear picture of fabrication and application of type II heterostructures.

The exponentially growing works on 2D materials have resulted in both high scientific interest and huge potential applications in nanocatalysis, optoelectronics, and spintronics. Of especial note is that the newly emerged and promising family of metal phosphorus trichalcogenides (MPX 3 ) contains semiconductors, metals, and insulators with intriguing layered structures and architectures. The bandgaps of the members in this family range from 1.3 to 3.5 eV, significantly enriching the application of 2D materials in the broad wavelength spectrum. In this review, emphasizing their remarkable structural, physicochemical, and magnetic properties, as well as the numerous applications in various fields, the innovative progress on layered MPX 3 crystals is summarized. Different from other layered materials, these crystals will advance a fascinating frontier in magnetism and spintronic devices with their especially featured atomic layered nanosheets. Thus, their crystal and electronic structures, along with some related researches in magnetism, are discussed in detail. The assortments of growth methods are then summarized. Considering their potential applications, the prominent utilization of these 2D MPX 3 nanoscrystals in catalysis, batteries, and optoelectronics is also discussed. Finally, the outlook of these kinds of layered nanomaterials is provided. Metal Phosphorus Trichalcogenidesions. Friedel [17] and Ferrand [18,19] discovered them in the late 1800s. Based on the interesting structure of these materials, significant research works were reported in the early 2000s. As expected, 2D MPX 3 phases share most of the abovementioned specific properties of 2D TMDs. According to the theoretical and experimental results, MPX 3 compounds are the most sought functional materials for their intermediate bandgaps ranging from 1.3 to 3.5 eV, [20,21] indicating their enhanced light absorption efficiency as compared to the TMD materials. In addition, their unusual intercalation-substitution or intercalation-reduction behavior as well as the incipient ionic conductivity promote their usage in Li-ion batteries, [22,23] gas storage, [24] and photo-electrochemical reactions. [25] Unlike TMDs, several MPX 3 materials show intrinsic anti-ferromagnetism below the Neel temperatures of 78 K for MnPS 3 , 116 K for FePS 3 , and 155 K for NiPS 3 . [26,27] Recently, Li et al. [28] predicted that transformation from the anti-ferromagnetism to ferromagnetism for exfoliated MnPSe 3 nanosheet will be reduced by carrier doping. And the Monte Carlo simulation reveals the Curie temperature of the doped MnPSe 3 nanosheets can reach 206 K, rendering it with potential for utilizations in spintronic devices at high temperature. Therefore, the members in the MPX 3 family have the abovementioned properties along with structural flexibility stemming from their van der Waals nature; thus, it is reasonable to assume that they will contribute to the next major frontier in 2D vdW layered materials.Herein, we emphasize on reviewing the impressive recent progress...

Owing to the excellent potential for fundamental research and technical applications in optoelectronic devices and catalytic activity for hydrogen evolution reaction (HER), transition metal dichalcogenides have recently attracted much attention. Transition metal sulfide nanostructures have been reported and demonstrated promising application in transistors and photodetectors. However, the growth of transition metal selenide nanostructures and their applications has still been a challenge. In this work, we successfully synthesized high-quality WSe2 nanotubes on carbon fibers via selenization. More importantly, through optimizing the growth conditions, ternary WS2(1–x)Se2x nanotubes were synthesized and the composition of S and Se can be systematically controlled. The as-grown WS2(1–x)Se2x nanotubes on carbon fibers, assembled as a working electrode, revealing low overpotential, high exchange current density, and small series resistance, exhibit excellent electrocatalytic properties for hydrogen evolution reaction. Our study provides the experimental groundwork for the synthesis of low-dimensional transition metal dichalcogenides and may open up exciting opportunities for their application in electronics, photoelectronics, and catalytic electrochemical reactions.

The desire for sustainable and clean energy future continues to be the concern of the scientific community. Researchers are incessantly targeting the development of scalable and abundant electro- or photo-catalysts for water splitting. Owing to their suitable band-gap and excellent stability, an enormous amount of transition-metal dichalcogenides (TMDs) with hierarchical nanostructures have been extensively explored. Herein, we present an overview of the recent research progresses in the design, characterization and applications of the TMD-based electro- or photo-catalysts for hydrogen and oxygen evolution. Emphasis is given to the layered and pyrite-phase structured TMDs encompassing semiconducting and metallic nanomaterials. Illustrative results and the future prospects are pointed out. This review will provide the readers with insight into the state-of-the-art research progresses in TMD based nanomaterials for water splitting.