Exfoliation in a low boiling point solvent and electrochemical applications of MoO₃

Abstract

MoO3 is a versatile two-dimensional transition metal oxide having applications in areas such as energy storage devices, electronic devices and catalysis. To efficiently utilize the properties of MoO3 arising from its two-dimensional nature exfoliation is necessary. In this work, the exfoliation of MoO3 is carried out in 2-butanone for the first time. The achieved concentration of the dispersion is about 0.57 mg·mL−1 with a yield of 5.7%, which are the highest values reported to date. These high values of concentration and yield can be attributed to a favorable matching of energies involved in exfoliation and stabilization of MoO3 nanosheets in 2-butanone. Interestingly, the MoO3 dispersion in 2-butanone retains its intrinsic nature even after exposure to sunlight for 24 h. The composites of MoO3 nanosheets were used as an electrode material for supercapacitors and showed a high specific capacitance of 201 F·g−1 in a three-electrode configuration at a scan rate of 50 mV·s−1.

Design Principles and Insights into the Liquid-Phase Exfoliation of Alpha-MoO3 for the Production of Colloidal 2D Nano-inks in Green Solvents

“…In previous works, different conditions for the LPE of α-MoO 3 were reported, employing different solvents such as NMP, various alcohols, , and water/surfactant mixtures. , It is possible to predict the LPE suitability of a solvent by resorting to several models, such as by considering the surface tension compatibility and the Hildebrand parameters . However, the mostly used and reliable way is to apply the Hansen solubility parameter (HSP) theory, commonly employed in polymer chemistry to predict the solubility, but demonstrated to work well also for LPE 2D materials. − The HSP theory states that the smaller is the interaction radius between the material and the solvent, the better will be the stability (eq ) where δ d2 is the dispersive component for the material chosen, δ d1 is the dispersive component for the solvent, δ p2 and δ p1 are the polar components for the material and the solvent, respectively, and δ h2 and δ h1 are the hydrogen bonding contribution of the two.…”

“…In previous works, different conditions for the LPE of α-MoO 3 were reported, employing different solvents such as NMP, 52 various alcohols, 14,53 and water/surfactant mixtures. 54,55 It is possible to predict the LPE suitability of a solvent by resorting to several models, such as by considering the surface tension compatibility and the Hildebrand parameters. 56 However, the mostly used and reliable way is to apply the Hansen solubility parameter (HSP) theory, commonly employed in polymer chemistry to predict the solubility, but demonstrated to work well also for LPE 2D materials.…”

Recent advances in the fabrication of 2D metal oxides

“…Sricharan et al. reported an exfoliation of MoO 3 in a low boiling point solvent, which was carried out in 2-butanone for the first time and achieved the highest yield ( Sricharan et al., 2020 ). Additionally, the MoO 3 dispersions in 2-butanone exhibited ultrahigh stability and did not undergo any chemical transformation even upon light exposure.…”

Progress on two-dimensional binary oxide materials

“…Some researchers have used the top-down liquid-phase stripping method, 32 while others have used the bottom-up solvent method to grow ultra-thin nanosheets. 26 We present a comparison of the preparation methods, applications and corresponding performance 38,[271][272][273][274] of 2D SnO 2 and MoO 3 , as shown in Table 1. In fact, in addition to considering the final performance of the material, it also needs to consider issues such as cost, environmental protection, and time.…”