Thermally Oxidized MoS$_2$-Based Hybrids as Superior Electrodes for Supercapacitor and Photoelectrochemical Applications

Abstract: High electronic transport and reasonable chemical stability of molybdenum disulfide (MoS$_2$) make it very suitable for electrochemical applications. However, its energy storage capacity is still low compared with other nanostructures. In this work, pristine and thermally oxidized MoS$_2$ (O@MoS$_2$) based hybrids are introduced by a simple method with enhanced capacitive performance thanks to the contribution of synergistic effects. Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), elemental mapping, UV-Visible, and Raman analyses are employed to investigate the morphological and crystalline structure of the introduced hybrids. In detail, the highest gravimetric capacitance of ~205.1 Fg-1 is achieved for the MoS$_2$:O@MoS$_2$ hybrid with a mass ratio of 2:1 compared to pristine and other electrodes. This electrode is also accompanied by the longest discharging time and excellent cyclic stability of ~%113 after 2000 continuous charge-discharge cycles. In addition, photoelectrochemical testing of the introduced electrode leads to a ~63% increase in carrier photogeneration compared to MoS$_2$ due to the effective charge separation within the hybrid, which makes it suitable for water splitting and hydrogen production applications.