Multifunctional Co3O4/Ti3C2Tx MXene nanocomposites for integrated all solid-state asymmetric supercapacitors and energy-saving electrochemical systems of H2 production by urea and alcohols electrolysis

Co3O4/Ti3C2Tx MXene nanocomposites have been fabricated by vacuum filtration and hydrothermal-annealing methods, and their electrochemical performance were investigated for energy storage and conversion, systematically. As electrode materials, Co3O4/Ti3C2Tx MXene nanocomposites in 6 M KOH solution demonstrated the specific capacitance of 240.1 F g−1 at 0.1 A g−1 and the long-term cycle stability. The solid-state asymmetric supercapacitors exhibited an operating potential window of 1.4 V, a specific capacitance of 97.9 F g−1at 0.25 A g−1, an energy density of 95.9 Wh kg−1 at a power density of 630.4 W kg−1, and excellent long-term durability. Furthermore, the connected solid-state asymmetric supercapacitors inseries and parallels presented the promising practical applications. Besides, Co3O4/Ti3C2Tx nanocomposites displayed outstanding catalytic behaviors for energy-saving H2 generation by urea and alcohols electrolysis. The electrolyzer in KOH + CH3CH2OH electrolyte required only 1.33 V potential to deliver the current density of 0.5 A g−1. Especially, the elctrochemical system of H2 production by The electrolyzer and the powered solid-state asymmetric supercapacitors based on Co3O4/Ti3C2Tx nanocomposites was constructed, demonstrating outstanding properties of H2 production. Therefore, this study not only shows enormous potential of Co3O4/Ti3C2Tx nanocomposites as a portable power supply but also indicates its great opportunities in energy-saving H2 production in practical applications.