MXene‐based materials play an important role in the field of energy storage devices, owing to their layered structure with gravimetric/volumetric capacitances higher than that of graphene. However, owing to their tendency to bond to hydrogen or due to van der Walls forces, their performance is often reduced by the restacking of layers and subsequent reduction of their active surface area. In this work, we investigate the charge storage capacitance enhancement after inserting 1T‐phase WS2 nanospacers into the matrix of MXene Ti3C2 through a simple sonication‐assisted procedure, forming a 2D stack structure. We demonstrated that each exfoliation step enhances the capacitive behavior when compared to the starting MAX phase (Ti3AlC2). This new sandwich material shall have profound influence on the construction of 2D materials‐based supercapacitors.

Group 6 transition metal dichalcogenides (TMDs), such as MoS2 and WS2 have been extensively studied for various applications while few studies have delved into other TMDs such as platinum dichalcogenides. In this work, layered crystalline and amorphous platinum disulfide (PtS2) were synthesized, characterised and their fundamental electrochemical properties were investigated. Both materials exhibited inherent oxidation and reduction reactions which would limit their operating potential window for sensing applications. Amorphous phase materials are considered to be promising electrocatalysts due to the porous, and nanostructured morphology with high concentration of unsaturated active sites. The electrocatalytic performances towards oxygen reduction (ORR) and hydrogen evolution reactions (HER) of crystalline and amorphous PtS2 were analysed. Amorphous PtS2 was found to exhibit superior electrocatalytic performances towards ORR and HER as compared to crystalline PtS2. For HER, amorphous and crystalline PtS2 have overpotential values of 0.30 V and 0.70 V (vs. RHE) at current density of 10 mA cm−2, respectively. The influence of electrochemical reduction pre‐treatment on their catalytic behaviours was also investigated. Electrochemical reduction pre‐treatment on both crystalline and amorphous PtS2 removed the oxidized sulfate groups and increased the proportion of Pt0 oxidation state which exposed more catalytic sites. As such, these materials were activated and displayed improved ORR and HER performances. Electrochemically reduced amorphous PtS2 outperformed the untreated counterparts and exhibited the best HER performance with overpotential of 0.17 V (vs. RHE) at current density of −10 mA cm−2. These findings provide insights into the electrochemical properties of noble metal PtS2 in both crystalline and amorphous states which can be activated by electrochemical reduction pre‐treatment.

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Graphene oxide (GO) foils were modified by irradiation using 1.0 MeV Au+ ions, and their elemental composition before and after the ion irradiation was investigated using Rutherford back‐scattering spectroscopy (RBS). The surface morphology was studied using SEM, and changes in elemental composition and structure of GO in shallow subsurface were characterized by various spectroscopy techniques including X‐ray photoelectron spectroscopy and Raman spectroscopy. Electrical properties were determined using standard 2‐point method. The analyses indicate that the Au irradiation up to 1.0 × 1015 cm−1 results in removal of oxygen functionalities and growth of graphene domains, leading to a surface conductivity increase dependent on the applied ion fluence. The Au irradiation with excessive ion fluencies leads to the amorphization of GO foil structure.

Layered AIIIBVI chalcogenides represent an interesting class semiconductors, where most of adopting 2D structures. Unlike the typical sandwiched structure of transition metal dichalcogenides (TMDs), layered AIIIBVI chalcogenides like InSe and GaSe are composed of X−M−M−X motif where M is gallium/indium and X is sulfur/selenium/tellurium. The exception is InS, which adopt an orthorhombic 3D structure. Herein, we studied and compared the inherent electrochemical properties as well as the electrocatalytic performances towards hydrogen evolution (HER), oxygen evolution (OER) and oxygen reduction reaction (ORR) of indium monochalcogenides (InS, InSe and InTe). Inherent electrochemistry studies in phosphate buffered saline electrolyte showed that InS did not exhibit any inherent electrochemical signals when compared to bare glassy carbon electrode. However, InSe showed a reduction peak at −1.6 V while InTe had an oxidation peak at 0.2 V. The heterogeneous electron transfer (HET) rates of indium monochalcogenides were measured with [Fe(CN)6]3−/4− redox probe using cyclic voltammetry (vs. Ag/AgCl) at the scan rate of 100 mV s−1. It was found that InTe exhibited the best electrochemical performance with the fastest HET rate with highest obtained (3.7×10−3 cm s−1). InS showed the best electrocatalytic performance for HER with the lowest overpotential value of 0.92 V at current density of −10 mA cm−2. However, the performances of indium monochalcogenides were almost comparable to that of bare glassy carbon electrode and do not exhibit any improvements in electrocatalytic capabilities. This study provides insights into the electrochemical properties and electrocatalytic performances of layered AIIIBVI indium monochalcogenides which would influence potential applications.

Structural and compositional modification of 2D materials as graphene or graphene oxide (GO) are topical objects of nowadays due to their many technological applications. Ion irradiation of graphene based materials, as a method for improvement of their surface properties started recently. Ion mass, energy, and fluence are crucial for forming of GO electrical, optical, and mechanical properties. In this work, the GO films are irradiated with 500 keV He and Ga ions to different fluences. The ions with different masses and electronic/nuclear stopping power ratios, are chosen with the aim to examine mechanisms of radiation defect creation. The elemental composition of the GO is investigated using Rutherford back‐scattering (RBS) and elastic recoil detection analysis (ERDA) techniques. The structural and chemical changes are characterized by X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy and the electrical properties are determined by two‐point method. The RBS and ERDA analyses indicate deoxygenation and dehydrogenation of the irradiated GO surface. The thickness and the degree of O and H depletion depend on the ion mass. XPS and Raman spectroscopy show removal of oxygen functionalities and structural modifications leading to a decrease in the surface resistivity.

The influence of low fluence high‐energy ion irradiation on the modification of the ZnO surface structure and optical properties has been studied. ZnO samples of various orientations, namely, c‐plane (0001), a‐plane (11–20) and m‐plane (10–10), have been implanted with 30‐MeV Au ions with fluences ranging from 5 × 109 to 5 × 1011 cm−2. Rutherford backscattering spectrometry in the channelling mode (RBS‐C) and Raman spectroscopy has shown the distinct damage accumulation in the irradiated surface layer about 1 μm depending on the ZnO facet being to larger extent evidenced in the m‐plane ZnO. Contrary, the a‐plane ZnO has been exhibited the lowest Zn disorder. Using atomic force microscopy (AFM), a complex morphology was detected on the irradiated samples containing grains and exhibiting increased roughness, both growing with the Au implantation fluence mainly in m‐plane ZnO. Positron annihilation spectroscopy (PAS) has shown distinct defect accumulation at the Au‐ion fluence of 5 × 1011 cm−2, where RBS‐C and Raman spectroscopy indicated sudden disorder increase in the irradiated layers, probably the creation of more complex clusters of Zn and O vacancies 4VZn + 8VO initiated in connection with an overlap of individual ion impacts. Photoluminescence measurements have shown a distinct near‐band‐edge (NBE) luminescence, developing with the increasing Au‐ion fluence in various ZnO orientations. The m‐plane ZnO had the most progressively suppressed NBE in comparison with the other orientations.

Naturally available microclays are well-known materials with great adsorption capabilities that are available in nature in megatons quantities. On the contrary, artificial nanostructures are often available at high cost via precision manufacturing. Such precision nanomanufacturing is also typically used for fabrication of self-propelled micromotors and nanomachines. Herein, we utilized naturally available Cloisite microclays to fabricate autonomous self-propelled microrobots and demonstrated their excellent performances in pesticide removal due to their excellent adsorption capability. Six different modified Cloisite microrobots were investigated by sputtering their microclays with platinum (Pt) for the fabrication of platinum–Cloisite (Pt–C) microrobots. The obtained microrobots displayed fast velocities (v > 110 μm/s) with fast and efficient enhanced removal of the pesticide fenitrothion, which is also considered as improvised nerve agent. The fabricated Pt–C microrobots exhibited low cytotoxicity even at high concentrations when incubated with human lung carcinoma epithelial cells, which make them safe for human handling.