Fabrication of carbon-coated chromium nitride (CrN@C) and chromium oxynitride (CrON) nanoparticles by a thermal plasma technique for supercapacitor applications

Abstract

Across recent decades, escalating natural resource exploitation has precipitated amplified global warming, terrestrial contamination, and shifts in climatic patterns. Concurrently, the global energy demand has surged precipitously, driven by escalating urbanization, industrialization, and population expansion. Given these circumstances, the imperative to innovate novel materials becomes apparent. These materials stand as pivotal components in the progression of energy storage and conversion technologies, simultaneously may mitigating natural resource consumption. Transition metal carbide and nitride materials have recently been utilized for such applications due to their superior chemical stability, elevated melting points, resistance to non-oxidizing acids, thermal and electrical conductivities, and other advantageous properties. The current study focuses on the synthesis of carbon-coated chromium nitride (CrN@C) nanoparticles (NPs) via a one-step process by the thermal plasma arc discharge (TPAD) method. The TPAD technique is one of the physical methods for large-scale synthesis requiring short time to prepare several metal oxides, nitrides and alloy nanoparticles from different sources. Experiments were carried out in nitrogen (N2) and ammonia (NH3) gas environments at different plasma input powers. Other experiments were conducted in a nitrogen atmosphere with mixed phases such as chromium nitride and chromium oxide, respectively. It was named chromium oxynitride (CrON). The phase analysis and elemental compositions of the prepared NPs were examined using X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) results. The prepared CrN@C NPs have nearly spherical and core–shell (Core–CrN and Shell–carbon) morphologies, which were determined by transmission electron microscopy (TEM) analysis. The CrN@C NPs show superior electrochemical pseudocapacitive behavior with a higher specific capacitance of 481.3 F g−1 at a current density of 1 A g−1. The CrN@C NP electrode exhibited higher cycling stability with 88.2% capacitance retention after 5000 cycles at a current density of 10 A g−1. These results indicated that the plasma-prepared core shell CrN@C NPs are potential electrode materials for supercapacitor applications.