Selenium-enriched MoSe2 as an effective electrode material for supercapacitors and a photocatalyst for dye degradation

In this research, we synthesized 2D-corrugated sheet-like nanostructure of MoSe2 (MS) and selenium-enriched MoSe2 (MS-S) using a hydrothermal method to evaluate the electrochemical and photocatalytic performance. Electrochemical assessments revealed that MS-S exhibits an outstanding specific capacitance of 275 F g−1 at a scan rate of 10 mV s−1, showcasing its suitability as a symmetric supercapacitor. Particularly noteworthy is the outstanding energy density observed in MS-S, reaching 36.72 Wh kg−1, a value nearly seven times higher than that of MS (5.33 Wh kg−1). Furthermore, MS-S demonstrated remarkable capacitance retention, retaining 68 % of its initial capacitance even after 2000 cycles. In contrast, MS exhibited only 17 % retention over the same cycle count. Additionally, we evaluated the photocatalytic efficacy of the MS and MS-S samples in degrading rhodamine B (RhB) dye in a solution utilizing a 30 W white LED light source. Impressively, after 50 minutes of light exposure, MS-S displayed an outstanding degradation efficiency of up to 86 %, significantly surpassing the performance of MS. These results emphasize the immense potential of MS-S as a highly promising material suitable for a range of applications, including supercapacitors and dye degradation. [Display omitted] •Selenium-enriched MoSe2 nanoflower has been prepared using a hydrothermal method.•It delivered specific capacitance of 275 F g−1 at a scan rate of 10 mV s−1.•It exhibited an energy density of 36.72 Wh kg−1 at a power density of 400 W kg−1.•It showed an 86 % rhodamine B dye degradation rate with 50 minutes of illumination.•The higher k (0.034 min−1) is observed for Se excess MoSe2 than MoSe2 (0.025 min−1).