Phase‐Engineering of 1T/2H Molybdenum Disulfide by Using Ionic Liquid for Enhanced Electrocatalytic Hydrogen Evolution

Carbon-doped defect MoS2 co-catalytic Fe3+/peroxymonosulfate process for efficient sulfadiazine degradation: Accelerating Fe3+/Fe2+ cycle and 1O2 dominated oxidation

In order to accelerate Fe³⁺/Fe²⁺ cycle and boost singlet oxygen (¹O₂) generation in peroxymonosulfate (PMS) Fenton-like system, a co-catalyst of defect MoS₂ was prepared by C doping and C2-MoS₂/Fe³⁺/PMS system was structured. The removal efficiency of sulfadiazine (SDZ) antibiotics was nearly 100 % in 10 min in the system under the appropriate conditions ([co-catalysts] = 0.2 g/L, [PMS] = 0.1 mM, [Fe³⁺] = 0.4 mM, pH 3.5), and the reaction rate constant was 4.6 times that of Fe³⁺/PMS system. C doping MoS₂ could induce phase transition, yield more sulfur defects, and expedite electron transfer. Besides, exposed Mo⁴⁺ sites on C2-MoS₂ could significantly enhance the regeneration and stability of Fe²⁺ and further promote the activation of PMS. ·OH, SO₄·^-, and ¹O₂ were responsible for SDZ degradation in the system. Notably, ¹O₂ generation was efficiently promoted by sulfur defects and CO sites on C2-MoS₂, and ¹O₂ played the main role in SDZ degradation. Therefore, this co-catalytic system exhibited great anti-interference and stability, and organic contaminants could be efficiently and stably degraded in a 14-day long-term experiment. This work provides a new approach for improving the co-catalytic performance of MoS₂ for Fe³⁺ mediated Fenton-like technology, and offers a promising antibiotic pollutant removal strategy.

Functions and performance of ionic liquids in enhancing electrocatalytic hydrogen evolution reactions: a comprehensive review

As a green and renewable energy source, hydrogen can be produced by the electrolysis of water via the hydrogen evolution reaction (HER). Nevertheless, this method requires efficient and low-cost electro-catalysts to improve hydrogen production efficiency. Ionic liquids (ILs), with a unique combination of such superior properties as low vapor pressure, high electrical conductivity, high electrochemical stability, and a wide variety of functional groups, have found applications in electrochemical systems designed for efficient HER. Herein, we provide a comprehensive and updated review on the functions and performance of ILs used in electrochemical systems to enhance the HER. As the name suggests, ILs have been employed either as electrolytes by themselves, or as electrolyte additives. They also played many functional roles in the synthesis of HER electrocatalysts, including as the synthesis reaction solvent, reaction precursor as well as single/dual ion sources, binder and structure-directing agents of the catalysts. With the assistance of ILs, HER efficiency of electrocatalysts was improved significantly, resulting in decreased overpotentials in the range of 16–385 mV @ 10 mA cm⁻² and increased Tafel slopes in the range of 30–210 mV dec⁻¹. Lastly, the problems and challenges of ILs in electrocatalytic water electrolysis and HER are also discussed and their prospects considered.

Ionic liquids play multi-functions in synthesizing catalysts for HER such as electrolytes/electrolyte additives, reaction solvents, precursors, single/dual ion sources, binders, or morphological structure/phase structure directing agents.

Crystal facet and phase engineering for advanced water splitting

This review covers the principles and recent advances in facet and phase engineering of catalysts for photocatalytic, photoelectrochemical, and electrochemical water splitting. It suggests the basis of catalyst design for advanced water splitting.

Effect of morphology and phase engineering of MoS2 on electrochemical properties of carbon nanotube/polyaniline@MoS2 composites

This paper rationally designs the morphology and phase structure of carbon nanotube/polyaniline@MoS₂ (CNT/PANI@MoS₂) composites, with MoS₂ conductive wrapping growing vertically on the outer layer of the composites via hydrothermal method. The crystalline nature and chemical properties are characterized by X-ray diffraction (XRD), Flourier transformation infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS). Morphology and microstructures are determined by Scanning electric microscopy (SEM), Transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET). The developed composites possess excellent electrochemical properties (the specific capacitance is substantially increased by ~119%, reaching 700.0 F g^-1 after wrapping by MoS₂) and good cycling stability (after over 5000 cycles retains 80.8% capacitance) in three-electrode systems, which indicating that the unique morphology of MoS₂ shells endow the channels to composites for rapid charge transport and ionic diffusion. Furthermore, symmetric supercapacitors devices assembled with the CNT/PANI@MoS₂ composites achieve specific capacitance of 459.7 F g^-1 at 1 A g^-1, capacitance retention is 97.4% after 10,000 cycles and reach superior energy density of 40.9 Wh kg^-1 at the power density of 400 W kg^-1. This strategy of three-dimensional wrapping method may open up a new potential to relieve the dilemma of degraded performance of supercapacitor, while improving the capacitance and stability for supercapacitors.