In this work, a feasible one-pot approach to synthesize manganese oxide/graphene composites, the so-called plasma-enhanced electrochemical exfoliation process (PE³P), has been developed. Herein, a composite of graphene decorated with manganese oxide nanoparticles was prepared via PE³P from a KMnO₄ solution and graphite electrode under a voltage of 70 V in an ambient environment. By controlling the initial KMnO₄ concentration, we obtained distinct MnO₂/graphene samples. The prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy. The electrochemical measurements of the MnO₂/graphene composites revealed that the specific capacitance of the samples is approximately 320 F g^–1 at a scan rate of 10 mV s^–1, which is comparably very high for manganese oxide/carbon-based supercapacitor electrode materials. Considering the simple, low-cost, one-step and environmentally friendly preparation, our approach has the potential to be used for the fabrication of MnO₂/graphene composites as the electrode materials of supercapacitors.

The research community has witnessed an exceptional increase in exploring graphene related two-dimensional materials (GR2Ms) in many innovative applications and emerging technologies. However, simple, low-cost, sustainable, and eco-friendly methods to manufacture large quantities and high-quality GR2Ms still remain an unsolved challenge. To address limitations of conventional wet chemical-based exfoliation methods using graphite resources, the top-down irradiation approach has proven to be an ultrafast, effective, and environmentally friendly technology for scalable exfoliation, production, and processing of GR2Ms providing new properties for emerging applications. Significant advancements have been made for preparation of broad range of GR2Ms from graphite, such as graphene, graphene oxide, and reduced graphene oxide, and their doped, functionalized and modified forms over the past two decades, thanks to the availability of photon and ion irradiation techniques, such as microwave, infrared, ultraviolet, solar, x-ray, gamma, laser, and plasma. This review presents recent advances on the application of these various irradiation techniques and highlights their mechanism, differences in properties of prepared GR2Ms, and their advantages and disadvantages in comparison with other conventional methods. The review provides an insight into the irradiation strategies and their prospective applications to produce, at a large scale, low-cost, high-quality GR2Ms for practical applications in transparent electrodes, optoelectronic devices, sensors, supercapacitors, protective coatings, conductive inks, and composites.

We herein present an alternative geometry of nanostructured carbon cathode capable of obtaining a low turn-on field, and both stable and high current densities. This cathode geometry consisted of a micro-hollow array on planar carbon nanostructures engineered by femtosecond laser. The micro-hollow geometry provides a larger edge area for achieving a lower turn-on field of 0.70 V/µm, a sustainable current of approximately 2 mA (about 112 mA/cm²) at an applied field of less than 2 V/µm. The electric field in the vicinity of the hollow array (rim edge) is enhanced due to the edge effect, that is key to improving field emission performance. The edge effect of the micro-hollow cathode is confirmed by numerical calculation. This new type of nanostructured carbon cathode geometry can be promisingly applied for high intensity and compact electron sources.

Carbon Nanotube and Graphene Aerogels (CNTAs & GAs)- the world’s lightest 3D materials (GA isseven times lighter than air - a cubic meter weighs just 160 grams) attracted widespread attention due to their excellent mechanical compressible properties, high temperature and thermal stability, recyclable and highly efficient organic pollutants adsorption capability (GA can absorb up to 900 times its own weight in oil and do so quickly, with one gram of Aerogel able to absorb up to 68.8 grams of organics per second). In this review, we present briefly recent progress in synthesis methods for fabrication of 3D CNTAs andGAs and their emerging applications in the field of environmental protection such as removingoil, organic pollutants, arsenic ions and other toxic metalsfrom water. Furthermore, to assist advanced research for practical applications of these 3D materials, the technical challenges are discussed, and future research directions are proposed.

In our work, MoS₂/graphene/MOF hybrid materials were synthesized via a two-step process consisting of the plasma-assisted electrochemical preparation of MoS₂/graphene and the wet formation of Cu-based metal-organic framework (MOF). The hybrid materials were characterized with Field Emission Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, X-ray Diffraction and Raman Spectroscopy. Furthermore, some initial results on their electrochemical properties for hydrogen evolution and oxygen evolution reactions were also presented, showing the potential to be a bi-functional catalyst.