Adsorption and electrochemical properties of deep eutectic solvent-functionalized oxidized hydrogen-substituted graphyne and its composites with multi-walled carbon nanotubes

Abstract

Oxidized hydrogen-substituted graphyne (O-HsGY) was modified with eight kinds of choline chloride-based deep eutectic solvents (DESs), and the adsorption and electrochemical properties of the material were enhanced by dual driving of N-doping and DES modification. The resulting materials were composited with multi-walled carbon nanotubes (MWCNTs) to overcome the limitations of individual carbon nanomaterial applications. The structure and properties of the materials were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, Brunauer Emmett Teller and UV–Vis diffuse reflection spectroscopy, and the adsorption and electrochemical properties of the materials were studied. Characterization results showed that the obtained materials had wide interlayer spacing (0.403 nm), abundant pore structure, and large forbidden band width (1.68 eV). The modification of DESs severely affected the π-π conjugation of graphyne, thereby enhanced the adsorption capacity of myricetin. The cyclic voltammetry curve showed that DESs modification and composite with MWCNTs could effectively improve the specific capacitance of the materials, and the composite electrode had obvious redox potential peak, which indicate that it introduced pseudocapacitance to the materials. In addition, electrochemical impedance spectroscopy and galvanostatic charge–discharge curves also showed that the electrodes prepared by these materials had small resistance value and good electrochemical reversibility. Therefore, it provided a reference for the development of new carbon nanomaterials and their applications in the fields of separation analysis, adsorption and energy storage.