Black phosphorus (BP) is a new rediscovered layered material, which has attracted enormous interests in the field of electrocatalysis. Recent investigations reveal that bulk BP is a promising electrocatalyst for oxygen evolution reactions (OER), whereas its bulk crystal structure restricts sufficient active sites for achieving highly efficient OER catalytic performances. Toward this end, few‐layer BP nanosheets prepared by facile liquid exfoliation are applied as electrocatalysts and exhibit preferable electrocatalytic OER activity in association with structural robustness; subsequently, the dependence of current density and applied bias potential on the concentration of OH− has also been uncovered. Most importantly, we are aware that reduction in the thickness of BP nanosheets would generate extra active sites from the ultrathin planar structure and complimenting to the electrocatalytic activities. It is further anticipated that the current work might provide further implementation about the OER performance of BP nanosheets, thereby, offering extendable availabilities for BP‐based electrocatalysts in constructing high‐performance OER devices.

Large-size 2D black phosphorus (BP) nanosheets have been successfully synthesized by a facile liquid exfoliation method. The as-prepared BP nanosheets are used to fabricate electrodes for a self-powered photodetector and exhibit preferable photoresponse activity as well as environmental robustness. Photoelectrochemical (PEC) tests demonstrate that the current density of BP nanosheets can reach up to 265 nA cm −2 under light irradiation, while the dark current densities fluctuate near 1 nA cm −2 in 0.1 M KOH. UV-vis and Raman spectra are carried out and confirm the inherent optical and physical properties of BP nanosheets. In addition, the cycle stability measurement exhibits no detectable distinction after processing 50 and 100 cycles, while an excellent on/off behavior is still preserved even after one month. Furthermore, the PEC performance of BP nanosheets-based photodetector is evaluated in various KOH concentrations, which demonstrates that the as-prepared BP nanosheets may have a great potential application in self-powered photodetector. It is anticipated that the present work can provide fundamental acknowledgement of the performance of a PEC-type BP nanosheets-based photodetector, offering extendable availabilities for 2D BPbased heterostructures to construct high-performance PEC devices.

Self‐powered photodetectors are considered as a new type of photodetectors enabling self‐powered photodetection without external power. The excellent photoresponsivity, fast photoresponse rate, low dark current, and large light on/off ratio of these photodetectors have attracted wide interest among scholars. 2D materials are widely used in self‐powered photodetectors due to their excellent optical and electrical properties, unique 2D structures, and their capabilities to exhibit excellent photodetection performance. According to the self‐driving mechanism of 2D material‐based self‐powered photodetectors, they are divided into three categories: p–n junction photodetectors, Schottky junction photodetectors, and photoelectrochemical photodetectors. From these three perspectives, the research progress of 2D material‐based self‐powered photodetectors is summarized in detail here. Research reports indicate that 2D material‐based self‐powered photodetectors have excellent self‐powered photoresponse behavior, good light on/off characteristics, and wideband spectral response ranges. The excellent photoresponse performance of 2D material‐based self‐powered photodetectors facilitates their potential applications in the field of optoelectronic devices. In particular, self‐powered photodetectors have great potential as novel emerging self‐driven optoelectronic devices. Finally, directions for the further development of 2D material‐based self‐powered photodetectors are anticipated.

The band gap of few‐layered 2D material is one of the significant issues for the application of practical devices. Due to the outstanding electrical transport property and excellent photoresponse, 2D InSe has recently attracted rising attention. Herein, few‐layered InSe nanosheets with direct band gap are delivered by a facile liquid‐phase exfoliation approach. We have synthesized a photoelectrochemical (PEC)‐type few‐layered InSe photodetector that exhibits high photocurrent density, responsivity, and stable cycling ability in KOH solution under the irradiation of sunlight. The detective ability of such PEC InSe photodetector can be conveniently tuned by varying the concentration of KOH and applied potential suggesting that the present device can be a fitting candidate as an excellent photodetector. Moreover, extendable optimization of the photodetection performance on InSe nanosheets would further enhance the potential of the prepared InSe in other PEC‐type devices such as dye‐sensitized solar cells, water splitting systems, and solar tracking equipment.

We have fabricated a novel sunlight photo-detector based on a MoS 2 /graphene heterostructure. The MoS 2 /graphene heterostructure was prepared by a facile hydrothermal method along with a subsequent annealing process followed by a substrate-induced high selective nucleation and growth mechanism. The microstructures and morphologies of the two-dimensional MoS 2 /graphene heterostructure can be experimentally confirmed by x-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and a UV-vis absorption spectrometer. Photoresponse investigations performed by a photoelectrochemical (PEC) measurement system indicate that the synthesized MoS 2 /graphene heterostructure shows superior photoresponse activities under the illumination of sunlight in contrast with bare MoS 2 and graphene. The improved photoresponsivity can be attributed to the enhanced light absorption, strong lightmatter interaction and the extremely efficient charge separation of the heterostructure. The structure and performances of the MoS 2 /graphene heterostructure suggest promising applications in the field of photonics and optoelectronics. RECEIVED

A convenient hydrothermal intercalation/exfoliation method for large-scale manufacturing of bismuth telluride (Bi 2 Te 3 ) nanosheets is reported here. Lithium cations can be intercalated between the layers of Bi 2 Te 3 using the reducing power of ethylene glycol in the common hydrothermal process, and high quality Bi 2 Te 3 nanosheets with thickness down to only 3-4 nm are obtained by removing lithium in the following exfoliating process. Scanning electron microscopy, transmission electron microscopy and Raman spectrum characterizations confirm that the high yield of Bi 2 Te 3 nanosheets with good quality were successfully achieved and the sizes of the immense nanosheets reached 200 nm width and 1 mm length. This hydrothermal intercalation/exfoliation method is general, as it has been extended to other layered materials, such as Bi 2 Se 3 and MoS 2 . Our results suggest a simple route for the large-scale production of thin and flat Bi 2 Te 3 nanosheets, which may be beneficial to further electronic and spintronics applications.

A novel binder-free electrode material of NiMoO4@CoMoO4 hierarchical nanospheres anchored on nickel foam with excellent electrochemical performance has been synthesized via a facile hydrothermal strategy. Microstructures and morphologies of samples are characterized by X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Besides, the effect of Ni/Co molar ratios of raw materials on electrochemical behaviors is also investigated by cyclic voltammetry, galvanostatic charge-discharge measurements, cycling tests and electrochemical impedance spectroscopy methods. Remarkably, the resulting NiMoO4@CoMoO4 hierarchical nanospheres with a Ni/Co molar ratio of 4 : 1 exhibit greatly enhanced capacitive properties relative to other components and display a high specific capacitance of 1601.6 F g(-1) at the current density of 2 A g(-1), as well as better cycling stability and rate capability. Moreover, a symmetric supercapacitor is constructed using NiMoO4@CoMoO4 nanospheres as the positive and negative electrodes with one piece of cellulose paper as the separator, which shows good electrochemical performance. Such enchanced capacitive properties are mostly attributed to the synergistic effect of nickel and cobalt molybdates directly deposited on the conductive substrate and their novel hierarchical structure, which can provide pathways for fast diffusion and transportation of ions and electrons and a large number of active sites. The results imply that the NiMoO4@CoMoO4 hierarchical nanospheres could be promising candidates for electrochemical energy storage.

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