Materials with few layers have been subjected to extensive research for the last few decades owing to their remarkable properties as for example catalysts, optical and electrical devices, or sensors. ...The properties and electronic structure of these materials can be tailored by the introduction of substituents. In the case of more reactive species, the modification also can improve stability, which is also an important factor with respect to device fabrication. This review focuses on monoelemental layered materials of Group 15 elements (pnictogens) and in particular their modification, leading to better ambient stability and/or different properties by covalent and non‐covalent modifications. The future modification and application of pnictogens are outlined.
2D‐Pniktogene: Schichtförmige Materialien zeigen bemerkenswerte Eigenschaften, z. B. als Katalysatoren, in optischen und elektrischen Funktionseinheiten und als Sensoren. Dieser Kurzaufsatz diskutiert aktuelle Fortschritte bei der Exfoliation und Modifikation von 2D‐Schichtmaterialien aus Elementen der Gruppe 15.
In article number 1900994, Martin Pumera and co‐workers report a new approach for fabricating desired, active electrodes for electrochemical energy applications involving metal 3D‐printing and atomic ...layer deposition (ALD). By combining 3D‐printing and ALD, tailored electrodes with conformed catalyst layers on 3D‐printed bases, with any shape, can be achieved. Stainless steel 3D‐printed electrodes are modified with TiO2 by ALD and their photoelectrochemical properties are investigated to illustrate proof‐of‐concept.
Abstract The magnetic phase transition is explored in CrSBr flakes through non‐magnetic ion irradiation, revealing a novel method for magnetic control in two‐dimensional (2D) materials. The rise and ...fall of the ferromagnetic phase is observed in antiferromagnetic CrSBr with increasing the irradiation fluence. The irradiated CrSBr shows ferromagnetic critical temperature ranging from 110 to 84 K, well above liquid N 2 temperature. Raman spectroscopy reveals phonon softening, suggesting the formation of defects. These findings not only highlight CrSBr's potential in spintronics, but also present ion irradiation as an effective tool for tuning magnetic properties in 2D materials, opening new avenues for the development of spintronic devices based on air‐stable van der Waals semiconductors.
Abstract
Layered A
III
B
VI
chalcogenides represent an interesting class semiconductors, where most of adopting 2D structures. Unlike the typical sandwiched structure of transition metal ...dichalcogenides (TMDs), layered A
III
B
VI
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 A
III
B
VI
indium monochalcogenides which would influence potential applications.
MXenes, a family of two-dimensional (2D) transition metal carbides, have been discovered as exciting candidates for various energy storage and conversion applications, including green hydrogen ...production by water splitting. Today, these materials mostly remain interesting objects for in-depth fundamental studies and scientific curiosity due to issues related to their preparation and environmental stability, limiting potential industrial applications. This work proposes a simple and inexpensive concept of composite electrodes composed of molybdenum- and titanium-containing MAX phases and MXene as functional materials. The concept is based on the modification of the initial MAX phase by the addition of metallic Ni, tuning Al- and carbon content and synthesis conditions, followed by fluoride-free etching under alkaline conditions. The proposed methodology allows producing a composite electrode with a well-developed 3D porous MAX phase-based structure acting as a support for electrocatalytic species, including MXene, and possessing good mechanical integrity. Electrochemical tests have shown a high electrochemical activity of such electrodes towards the hydrogen evolution reaction (HER), combined with a relatively high areal capacitance (up to 10 F cm
−2
).
The MAX phase/MXene/Ni composite with 3D porous structure prepared was assessed for energy conversion and storage application, using the hydrogen evolution reaction under alkaline conditions as a model system.
Magnetic excitations in layered magnetic materials that can be thinned down to the twodimensional (2D) monolayer limit are of high interest from a fundamental point of view and for applications ...perspectives. Raman scattering has played a crucial role in exploring the properties of magnetic layered materials and, even-though it is essentially a probe of lattice vibrations, it can reflect magnetic ordering in solids through the spin-phonon interaction or through the observation of magnon excitations. In bulk CrSBr, a layered A type antiferromagnet (AF), we show that the magnetic ordering can be directly observed in the temperature dependence of the Raman scattering response i) through the variations of the scattered intensities, ii) through the activation of new phonon lines reflecting the change of symmetry with the appearance of the additional magnetic periodicity, and iii) through the observation, below the Néel temperature (TN) of second order Raman scattering processes. We additionally show that the three different magnetic phases encountered in CrSBr, including the recently identified low temperature phase, have a particular Raman scattering signature. This work demonstrates that magnetic ordering can be observed directly in the Raman scattering response of bulk CrSBr with in-plane magnetization, and that it can provide a unique insight into the magnetic phases encountered in magnetic layered materials.
Molybdenum disulfide (MoS
) is at the forefront of materials research. It shows great promise for electrochemical applications, especially for hydrogen evolution reaction (HER) catalysis. There is a ...significant discrepancy in the literature on the reported catalytic activity for HER catalysis on MoS
. Here we test the electrochemical performance of MoS
obtained from seven sources and we show that these sources provide MoS
of various phase purity (2H and 3R, and their mixtures) and composition, which is responsible for their different electrochemical properties. The overpotentials for HER at -10 mA cm
for MoS
from seven different sources range from -0.59 V to -0.78 V vs. reversible hydrogen electrode (RHE). This is of very high importance as with much interest in 2D-MoS
, the use of the top-down approach would usually involve the application of commercially available MoS
. These commercially available MoS
are rarely characterized for composition and phase purity. These key parameters are responsible for large variance of reported catalytic properties of MoS
.
Molybdenum disulfide (MoS sub(2)) is at the forefront of materials research. It shows great promise for electrochemical applications, especially for hydrogen evolution reaction (HER) catalysis. There ...is a significant discrepancy in the literature on the reported catalytic activity for HER catalysis on MoS sub(2). Here we test the electrochemical performance of MoS sub(2) obtained from seven sources and we show that these sources provide MoS sub(2) of various phase purity (2H and 3R, and their mixtures) and composition, which is responsible for their different electrochemical properties. The overpotentials for HER at -10mAcm super(-2) for MoS sub(2) from seven different sources range from -0.59V to -0.78V vs. reversible hydrogen electrode (RHE). This is of very high importance as with much interest in 2D-MoS sub(2), the use of the top-down approach would usually involve the application of commercially available MoS sub(2). These commercially available MoS sub(2) are rarely characterized for composition and phase purity. These key parameters are responsible for large variance of reported catalytic properties of MoS sub(2). Origin is important to HER: A comparison study was carried out on various commercial and natural MoS sub(2) samples, highlighting numerous differences in phase composition, purity, and particle size. These differences were evaluated for their impact on the rather variable performances the MoS sub(2) samples showed as a catalyst for the hydrogen evolution reaction.
Metallic 1T‐phase transition metal dichalcogenides have been recognized for their desirable properties like high surface‐to‐volume ratio, high conductivity, and capacitive behavior, making them ...outstanding for catalytic and sensing applications. Herein, a hydrogen peroxide (H
2
O
2
) biosensor is constructed by the immobilization of hemoglobin (Hb) on 1T‐phase WS
2
(1T‐WS
2
) sheets, and entrapment by glutaraldehyde. 1T‐WS
2
not only displays electrocatalytic activity toward the reduction of H
2
O
2
but also provides a high surface‐to‐volume ratio and conductive platform for the immobilization of Hb and facilitation of its electron transfer to the electrode surface. The advantageous role of 1T‐phase WS
2
is further demonstrated for the construction of a heme‐based H
2
O
2
biosensor compared to its 1T‐phase MoS
2,
MoSe
2
, and WSe
2
counterparts. Synergistic interactions between 1T‐WS
2
and Hb result in a H
2
O
2
biosensor with high analytical performance in terms of wide range, sensitivity, selectivity, reproducibility, repeatability, and stability. These findings have profound impact in the research fields of electrochemical sensing and biodiagnostics.
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