The electrochemical behaviors of single-, few- and multi-layer graphene, graphene oxides, reduced graphene oxides, CVD graphene and three-dimensional graphene are discussed and critically evaluated, ...providing an up-to-date summary on the progress of the field.
•The electrochemistry of single-, few- and multi-layer graphene•The electrochemistry of graphene oxides, reduced graphene oxides•The electrochemistry of CVD graphene and three-dimensional graphene
Two dimensional (2D) materials exhibit highly useful materials properties. Graphene, single sheet transition metals dichalcogenides found plethora applications in various fields, including analytical ...chemistry. Layered black phosphorus and its single sheet variation (phosphorene) became popular material very recently due to its monoelemental composition, biocompatibility, electrochemical properties, tunable bandgap and resulting optical properties. Here we describe progress which was made towards analytical applications of black phosphorus and its single sheet counterpart, phosphorene.
•Layered black phosphorus and phosphorene show biocompatibility.•Phosphorene has interesting electrochemical properties, optical properties and tunable bandgap.•The analytical applications of black phosphorus are overviewed.
This Perspective illustrates how impurities in nanomaterials affect their electrocatalytic properties. The focus is on 1D and 2D nanomaterials, starting with carbon nanotubes, through graphene and ...transition metal dichalcogenides to black phosphorus, and closing the circle with graphene in 3D-printed materials. Through these examples, we show that detailed materials characterization is paramount prior to assigning catalytic properties to specific functionality. We show that while metallic impurities in nanocarbons and black phosphorus are often a source of perceived electrocatalysis of these materials, the different phase and valency impurities are often sources of electrocatalysis in transition metal dichalcogenides. These impurities should not be viewed negatively because if their amount is controlled, then they become dopants and can be beneficial for the intended applications of these nanomaterials.
Electrocatalytic or not? Carbon nanotubes (CNTs; see figure) are at the forefront of electrochemical research, but care should be taken when describing the electrochemistry, which is often caused by ...defects or impurities. A discussion on this aspect of their chemistry as well as important applications of CNTs for sensing and energy storage are presented.
Carbon nanotubes (CNTs) are in the forefront of electrochemical research. It has become clear that an understanding of the fundamental reasons for the electrochemical activity of CNTs is essential for further progress in the field. This review provides a critical discussion of the fundamental reasons behind the electrochemical and “electrocatalytic” activity of CNTs as well as on important applications of CNTs for sensing, biosensing, and energy storage systems.
Electrocatalytic or not? Carbon nanotubes (CNTs; see figure) are at the forefront of electrochemical research, but care should be taken when describing the electrochemistry, which is often caused by defects or impurities. A discussion on this aspect of their chemistry as well as important applications of CNTs for sensing and energy storage are presented.
While the electrochemistry of redox-active ions or molecules has been studied for decades, the electrochemistry of individual nanoparticles remains largely unexplored. In this issue of ACS Nano, ...Stuart et al. report the direct electrochemical detection of impacting carbon C60 nanoparticles in a non-aqueous solution. This study opens up the possibility of detecting and counting various redox-active inorganic, organic, and carbon-based nanoparticles, one by one, in colloids and suspensions by a simple and highly sensitive technique. The method developed by Stuart et al. enables the determination of the type, size, and concentration of the nanoparticles. One can foresee a wide scope of potential applications, ranging from the environmental monitoring of nanoparticles to the detection of self-propelled autonomous nano- and micromachines.
In the past few years, we have witnessed rapid developments in the realization of the old nanotechnology dream, autonomous nanosubmarines. These nanomachines are self-powered, taking energy from ...their environment by electrocatalytic conversion of chemicals present in the solution, self-propelled by flux of the electrons within the submarine and the hydronium ions on the surface of the nanosub, powering it in the direction opposite to that of the flux of the hydronium. These nanosubmarines are responsive to external fields, able to follow complex magnetic patterns, navigate themselves in complex microfluidic channels, follow chemical gradients, carry cargo, and communicate with each other. This minireview focuses on a discussion of the fundamentals of the electrophoretic mechanism underlying the propulsion of this sort of nanosub, as well as a demonstration of the proof-of-concept capabilities of nanosubmarines.
Top‐down methods are of key importance for large‐scale graphene and graphene oxide preparation. Electrochemical exfoliation of graphite has lately gained much interest because of the simplicity of ...execution, the short process time, and the good quality of graphene that can be obtained. Here, we test three different electrolytes, that is, H2SO4, Na2SO4, and LiClO4, with a common exfoliation procedure to evaluate the difference in structural and chemical properties that result for the graphene. The properties are analyzed by means of scanning transmission electron microscopy (STEM), Raman spectroscopy, and X‐ray photoelectron spectroscopy. We then tested the graphene materials for electrochemical applications, measuring the heterogeneous electron transfer (HET) rates with a Fe(CN)63−/4− redox probe, and their capacitive behavior in alkaline solutions. We correlate the electrochemical features with the presence of structural defects and oxygen functionalities on the graphene materials. In particular, the use of LiClO4 during the electrochemical exfoliation of graphite allowed the formation of highly oxidized graphene with a C/O ratio close to 4.0 and represents a possible avenue for the mass production of graphene oxide as valid alternative to the current laborious and dangerous chemical procedures, which also have limited scalability.
Which electrolyte? Three different electrolytes, H2SO4, Na2SO4, and LiClO4, are tested with a common exfoliation procedure to evaluate the difference in structural and chemical properties that result for graphene and graphene oxide. Use of LiClO4 during the electrochemical exfoliation of graphite allowed the formation of highly oxidized graphene with a C/O ratio close to 4.0 and represents a possible avenue for the mass production of graphene oxide as valid alternative to the current laborious and dangerous chemical procedures with limited scalability.
3D printing has attracted the attention of analytical chemists. 3D printing possesses the merits of fast and low-cost fabrication of geometrically complex 3D structures and has been employed in the ...fields of microfluidic devices, electrochemical sensors and biosensors, separation sciences, sample pretreatment, and wearable sensors. We focus on the applications and materials of 3D printing in microfluidic devices, separation sciences, and extraction over the last three years and we offer outlook. It is clear that the 3D printing in separation science is here to stay and with new materials development, to develop to on demand fabrication of separation tools.
•3D printing techniques show attractive merits in analytical chemistry.•Applications of 3D printing in microfluidic, separation sciences and extraction devices were summarized.•Materials for 3D printing in analytical chemistry were highlighted.•Future perspectives of 3D printing in analytical chemistry were discussed.
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