Precise design and synthesis of sub-nano scale catalysts with controllable electronic and geometric structures are pivotal for enhancing the hydrogen evolution reaction (HER) performance of molybdenum sulfide (MoS₂) and unraveling its structure-activity relationship. By leveraging transition molybdenum polysulfide clusters as functional units for multi-level ordering. Here, we successfully designed and synthesized MoS_x nanowire networks derived from [Mo₃S₁₃]²⁻ clusters via evaporation-induced self-assembly, which exhibit enhanced HER activity attributed to a high density of active sites and dynamic evolution behavior under cathodic potentials. MoS_x nanowire networks electrode yields a current density of 100 mA cm⁻² at 142 mV in 0.5 M H₂SO₄. This work provides an attractive prospect for optimizing catalysts at the sub-nano scale and offers insights into a strategy for designing catalysts in various gas evolution reactions.

Injectability empowers conductive hydrogels to transcend traditional limitations, unlocking a realm of possibilities for innovative medical, wearable, and therapeutic applications that can significantly enhance patient care and quality of life. Here, we report an injectable, self-healable, and reusable hydrogel obtained by mixing the concentrated poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) suspension (~ 2 wt.% solid content), polyvinyl alcohol (PVA), and borax. Leveraging the presence of reversible borax/hydroxyl bonds and multiple hydrogen bonds, this PEDOT:PSS/PVA hydrogel exhibits notable shear-thinning behavior and self-healing capabilities, enabling it to be injected as a gel fiber from a syringe. As-prepared injectable hydrogel also demonstrates an ultra-low modulus (~ 2.5 MPa), reduced on-skin impedance (~ 45% of commercial electrodes), and high signal-to-noise ratio (SNR) (~ 15–22 dB) in recording of electrocardiography (ECG), electromyography (EMG), and electroencephalogram (EEG) signals. Furthermore, the injectable hydrogels can be remolded and reinjected as the reusable electrodes, maintaining nearly identical electrophysiological recording capabilities and brain–computer interface (BCI) performance compared to commercial wet electrodes. With their straightforward fabrication, excellent material properties and electronic performance, ease of cleaning, and remarkable reusability, our injectable PEDOT:PSS/PVA hydrogels hold promise for advancements in BCI based electronics and wearable bioelectronics.

The weak van der Waals gap endows two dimensional transition metal dichalcogenides (2D TMDs) with the potential to realize guest intercalation and host exfoliation. Intriguingly, the liquid intercalation and exfoliation is a facile, low-cost, versatile and scalable strategy to modulate the structure and physiochemical property of TMDs via introducing foreign species into interlayer. In this review, firstly, we briefly introduce the resultant hybrid superlattice and disperse nanosheets with tailored properties fabricated via liquid intercalation and exfoliation. Subsequently, we systematically analyze the intercalation phenomenon and limitations of various intercalants in chemical or electrochemical methods. Afterwards, we intensely discuss diverse functionalities of resultant materials, focusing on their potential applications in energy conversion, energy storage, water purification, electronics, thermoelectrics and superconductor. Finally, we highlight the challenges and outlooks for precise and mass production of 2D TMDs-based materials via liquid intercalation and exfoliation. This review enriches the overview of liquid intercalation and exfoliation strategy, and paves the path for relevant high-performance devices.

As a clean, efficient, and sustainable energy, hydrogen is expected to replace traditional fossil energy. A series of studies focusing on morphology regulation, surface modification, and structural reconstruction have been devoted to improving the intrinsic catalytic activity of non-noble metal catalysts. However, complex system structure design and the mutual interference of various chemical components would hinder the further improvement of hydrogen evolution performance. In recent years, external field assisted hydrogen evolution reaction (HER) has become a new research hotspot. Herein, we systematically summarize the promoting effects of various external fields on catalytic hydrogen production from the aspects of system design and catalytic mechanism, including electric field, thermal field, optical field, magnetic field, and acoustic field. Ultimately, we discuss the key challenges facing this external field regulation strategy and put forward the prospect of future research topics. We sincerely expect that this review could not only provide a new insight into the basic mechanism of external-assisted catalysis, but also promote further research on improving HER performance from a more diverse and comprehensive perspective.

Amorphous materials are one kind of nonequilibrium materials and have become one of the most active research fields. Compared with crystalline solids, the theory of amorphous materials is still in infancy because their characteristic of atomic arrangement is more like liquid and has no long-range periodicity. Recently, as the representative of amorphous materials, amorphous molybdenum sulfide (a-MoS_x) with unique physical and chemical properties has been studied extensively. However, considerable debate surrounds the structure–property relationships of a-MoS_x owing to its diverse Mo-S motifs. Herein, we summarize recent discoveries and research results regarding a-MoS_x, whose structural characteristics, synthetic strategies, formation criteria, and comprehensive applications are discussed in detail. Finally, this review is ended with our personal insights and critical outlooks over the development of a-MoS_x.

Heteroatom doping is a promising approach to enhance catalytic activity by modulating physical properties, electronic structure, and reaction pathway. Herein, we demonstrate that appropriate Ni-doping could trigger a preferential transition of the basal plane from 2H (trigonal prismatic) to 1T′ (clustered Mo) by inducing lattice distortion and S vacancy (SV) and thus dramatically facilitate its catalytic hydrogen evolution activity. It is noteworthy that the unique catalysts did possess superior catalytic performance of hydrogen evolution reaction (HER). The rate of photocatalytic hydrogen evolution could reach 20.45 mmol·g⁻¹·h⁻¹ and reduced only slightly in the long period of the photocatalytic process. First-principles calculations reveal that the distorted Ni-1T′-MoS₂ with SV could generate favorable water adsorption energy (E_ad(H₂O)) and Gibbs free energy of hydrogen adsorption (∆G_H). This work exhibits a facile and promising pathway for synergistically regulating physical properties, electronic structure, or wettability based on the doping strategy for designing HER electrocatalysts.

Defect engineering is one of the effective strategies to optimize the physical and chemical properties of molybdenum disulfide (MoS₂) to improve catalytic hydrogen evolution reaction (HER) performance. Dislocations, as a typical defect structure, are worthy of further investigation due to the versatility and sophistication of structures and the influence of local strain effects on the catalytic performance. Herein, this study adopted a low-temperature hydrothermal synthesis strategy to introduce numerous dislocation-strained structures into the in-plane and out-of-plane of MoS₂ nanosheets. Superior HER catalytic activity of 5.85 mmol·g⁻¹·h⁻¹ under visible light was achieved based on the high-density dislocations and the corresponding strain field. This work paves a new pathway for improving the catalytic activity of MoS₂ via a dislocation-strained synergistic modulation strategy.