(Invited) 2D Nitride Mxenes with Unusual Chemistries for Carbon-Neutral Energy

Abstract

The large-scale shift towards renewable energy technology requires the ability to reliably convert and store electrochemical energy. This technology is still limited in terms of performance, cost, and/or ease of utilization. In recent years, two-dimensional (2D) materials have been explored as low-cost, high-performing catalysts and electrodes for the reliable conversion and storage of electrochemical energy. Of these 2D materials, a special class of carbides and nitrides, known as MXenes, have gained popularity due to their high tunability, conductivity, and high surface area-to-volume ratio. From these carbide and nitride MXenes, the nitrides have received less attention due to a lack of reliable synthesis methods, despite being theorized to outperform their carbide counterparts. In this presentation, I will present on the oxygen-assisted molten salt fluoride synthesis method developed in my group to produce phase-pure nitride MXenes. Along with this, I will provide evidence of the enhanced capabilities of the nitride family of MXenes compared to carbides, sulfides, and oxides, when applied in the nitrogen reduction reaction (NRR), hydrogen evolution reaction (HER), and supercapacitor applications. In each of these fields, the enhanced performance is investigated using in-situ/operando spectroelectrochemical techniques. I will wrap up by discussing the future directions in the field of MXenes that require further attention for the full exploitation of their properties in electrochemical energy storage and conversion systems to attain carbon-neutral energy.