The synthesis of CoS/MnCo2O4-MnO2 nanocomposites for supercapacitors and energy-saving H2 production

In this study, CoS/MnCo 2 O 4 -MnO 2 (CMM) nanocomposites were synthesised by hydrothermal + electrochemical deposition and their electrochemical properties were systematically investigated for supercapacitors and energy-saving H 2 production. As an electrode material for supercapacitor, CMM achieves a specific capacitance of 2320 F g -1 at 1 A g -1 , and maintains a specific capacitance of 1216 F g -1 at 10 A g -1 . It also shows good cycling stability (72.8 % capacitance retention after 8000 cycles). The aqueous asymmetric supercapacitor (CMM//AC ASC) assembled from CMM electrodes (positive) and AC electrodes (negative) exhibited high energy storage capacity (887.86 F g -1 specific capacitance at a current density of 1 A g -1 ), good rate performance and cycling stability. In addition, CMM shows excellent UOR and MOR performances energy-saving H 2 production. compared to OER (1.635 V) at 20 mA cm -2 , The potentials was reduced by 213 mV for UOR and 233 mV for MOR, respectively. MMC electrodes maintain a stable catalytic current for 100 h and 55 h, respectively. Furthermore, As a bifunctional catalyst for both UOR (MOR) and HER, CMM exhibits excellent catalytic and stability performances.Therefore, this study shows the promising practical applications of CMM nanocomposites for energy storage and energy-saving H 2 production. • CoS/MnCo 2 O 4 -MnO 2 (CMM) nanocomposites were synthesised by hydrothermal and then electrochemical deposition. • CMM achieves a specific capacitance of 2320 F g -1 at 1 A g -1 , and maintains a specific capacitance of 1216 F g -1 at 10 A g -1 . It also shows good cycling stability (72.8 % capacitance retention after 8000 cycles). • The aqueous asymmetric supercapacitor (CMM//AC ASC) assembled from CMM electrodes (positive) and AC electrodes (negative) exhibited high energy storage capacity (887.86 F g -1 specific capacitance at a current density of 1 A g -1 ). • CMM shows excellent UOR and MOR performances energy-saving H 2 production. compared to OER (1.635 V) at 20 mA cm -2 , The potentials was reduced by 213 mV for UOR and 233 mV for MOR, respectively. In this study, CoS/MnCo 2 O 4 -MnO 2 (CMM) nanocomposites were synthesized by hydrothermal and then electrochemical deposition. Their electrochemical properties were systematically investigated for supercapacitors and energy-saving H 2 production. As an electrode material for supercapacitor, CMM demonstrates a specific capacitance of 2320 F g -1 at 1 A g -1 , and maintains a specific capacitance of 1216 F g -1 at 10 A g -1 . It also shows 72.8 % capacitance retention after 8000 cycles. The aqueous asymmetric supercapacitor exhibited high energy storage capacity (887.86 F g -1 specific capacitance at a current density of 1 A g -1 ), good rate performance and cycling stability. Besides, CMM shows outstanding urea oxidation reaction(UOR) and glycol oxidation reaction (MOR) performances for H 2 production. Compared to oxygen evolution reaction (OER) (1.635 V) at 20 mA cm -2 , the potentials were reduced by 213 mV for UOR and 233 mV for MOR, respectively. Therefore, this study shows the promising practical applications of CMM nanocomposites for energy storage and energy-saving H 2 production.