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Molybdenum disulfide, as an electronic highly-adjustable catalysts material, tuning its electronic structure is crucial to enhance its intrinsic hydrogen evolution reaction (HER) activity. Nevertheless, there are yet huge challenges to the understanding and regulation of the surface electronic structure of molybdenum disulfide-based catalysts. Here we address these challenges by tuning its electronic structure of phase modulation synergistic with interfacial chemistry and defects from phosphorus or sulfur implantation, and we then successfully design and synthesize electrocatalysts with the multi-heterojunction interfaces (e.g., 1T0.81-MoS2@Ni2P), demonstrating superior HER activities and good stabilities with a small overpotentials of 38.9 and 95 mV at 10 mA/cm2, a low Tafel slopes of 41 and 42 mV/dec in acidic as well as alkaline surroundings, outperforming commercial Pt/C catalyst and other reported Mo-based catalysts. Theoretical calculation verified that the incorporation of metallic-phase and intrinsic HER-active Ni-based materials into molybdenum disulfide could effectively regulate its electronic structure for making the bandgap narrower. Additionally, X-ray absorption spectroscopy indicate that reduced nickel possesses empty orbitals, which is helpful for additional H binding ability. All these factors can decrease Mo-H bond strength, greatly improving the HER catalytic activity of these materials.

energy, including solar energy, wind energy, water energy, and bioenergy. Triboelectric nanogenerator (TENG), based on contact electrification and electrostatic induction, was emerging in 2012, [1] which has arisen enormous interest in recent years owing to its ability to harvest energy and convert the energy to electrical energy from human everyday activities, [2,3] the environment of nature, [4][5][6] and similar mechanical motions. TENG shows a wide range of potential applications, such as identified keyboard, [7] sensor power for monitoring driver behavior, [8] smart seat as signal generator, [9] or even the power source for implantable devices, [10] and wearable electronics. [11] Among various kinds of triboelectric materials, poly(dimethylsiloxane) (PDMS) is a kind of ideal negative friction layer candidate due to its high electronegativity, good transparency, and flexibility. [12] Although there are so many advantages of PDMS, there is still a long way to improve the output characteristics of PDMS-based TENG, which can better satisfy the energy needs of various devices in the future. Many researchers have proposed diverse methods such as increasing actual triboelectric area by the preparation of surface micro-nanostructures using photolithography templates, [13][14][15] and surface physical/chemical treatments. [14,16] Unfortunately, these methods often require complicated processes or delicate instruments. In addition, dielectric materials [17,18] or conductive materials [19,20] can be doped in PDMS to build micro-capacitance structures to improve output characteristics. However, these often deteriorate the transparency and flexibility of TENG. Although the PTFE material has attracted much attention due to high electronegativity for TENG applications, [21][22][23][24][25][26][27] its transparence is still far from satisfactory. Here it should be noted that the integration of flexible and transparent characteristics has attracted much attention, and various kinds of novel optoelectronic and electronic devices have been developed in recent years, including artificial skins, [28,29] various sensors, [30,31] and transistors. [32,33] In this study, one simple and low-cost method was demonstrated to modify the PDMS film as the negative friction layer of TENG without degrading its transparency and flexibility, and meanwhile the output performance was obviously improved.

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The triboelectric nanogenerator (TENG), based on triboelectrification and electrostatic induction, has been proven to be an ideal power supply device which converts all kinds of mechanical energy into electrical energy. However, high cost of fabrication and modification prevents wide application. In this work, we demonstrated a simple, cost-effective but efficient method, in which the friction pair materials, i.e., copper electrode and polydimethylsiloxane (PDMS), were both patterned by using sandpaper templates. The copper electrode and PDMS were patterned with sandpaper-like morphology and sandpaper-complementary-like morphology, respectively. Compared with TENG devices with nonpatterned or single-sided patterned friction layer, TENG devices with two-sided patterned friction layers have better output properties when the sandpaper templates used for the PDMS and copper electrode have the same large grit sizes (above 2000) because of closer contact and more sufficient friction. When the sandpaper templates used for the PDMS and copper electrode have the same grit size of 10 000, the maximum output short-circuit current density, open-circuit voltage, transfer charge quantity, and power density of as-prepared TENG devices are 3.89 mA/m2, 200 V, 76 nC, and 4.36 W/m2, respectively. Overall, patterning microstructure morphology and corresponding complementary morphology on the respective two sides of friction pair shows efficient improvement for the performance of the TENG device, providing a good guidance for its modification.

Selenide-rich bimetallic selenide spheres with core–shell nanostructure were rationally designed and synthesized towards superior battery-supercapacitor hybrid device as the cathode electrode by selenizing hydrothermal-derived Ni–Co spheres.

New 2D bismuth oxychalcogenide nanosheets have excellent theoretical properties such as high electronic mobility and excellent oxidation resistance, which have good application prospective for optoelectronic devices. In this paper, during the synthesis process via mild hydrothermal route, ammonium bismuth citrate (C6H13BiN2O7·H2O) is selected as Bi source. Both Bi2O2S and Bi2O2Se nanosheets (lateral size: over 2.0 µm, thickness: ≈ 5.0 nm) are synthesized successfully using thiourea (CH4N2S) as S source, and sodium selenite (Na2O3Se) as Se source, respectively. The as‐synthesized Bi2O2S and Bi2O2Se materials have desirable nanosheet‐like morphologies. After adding C6H13BiN2O7·H2O, [(NH3)2C6H7O7]3‐ can intercalate between the interlayers of Bi2O2S or Bi2O2Se, limiting the growth along c‐axis direction, so that 2D sheets can be obtained. Finally, the photodetectors are fabricated based on Bi2O2S and Bi2O2Se films coated by thermal spraying. The experimental results show that the maximum responsivity and detectivity of Bi2O2S‐based photodetector are 0.059 A W‐1 and 6.77 × 109 Jones, respectively. As to Bi2O2Se‐based photodetector, the maximum responsivity and detectivity can reach 75.14 A W‐1 and 3.95 × 1012 Jones, respectively. The mild hydrothermal synthesis using ammonium bismuth citrate as Bi source is a universal and facile method to obtain Bi2O2S and Bi2O2Se nanosheets for optoelectronic applications.

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