Ultrathin ternary metal oxide Bi₂MoO₆ nanosheets for high performance asymmetric supercapacitor and gas sensor applications

Two dimensional (2-D), unstacked Bi₂MoO₆ nanosheets are directly grown on nickel foam and prepared as powder via easy, template-free hydrothermal route. The prepared material was systematically characterized using techniques viz XRD, Cs-TEM, HRTEM, FESEM, XPS, elemental mapping, EDS. Bi₂MoO₆ nanosheets grown on Nickel foam employed for supercapacitor application, whereas powder form was utilized to fabricate ethanol sensor. The electrochemical characteristics viz cyclic voltammetry (CV), galvanic charging-discharging (GCD), and electrochemical impedance spectroscopy (EIS) were investigated for Bi₂MoO₆ nanosheets grown nickel foam in 1 M KOH aqueous solution within −0.2 to 0.8 V potential window. The areal capacitance of 655.5 mF/cm² was achieved at 1 mA/cm² current density with the energy density of 22.76 × 10⁻³ Wh/cm² and 347.18 × 10⁻³ W/cm² power density. The 5000 charge–discharge cycles were performed with excellent capacitance retention. The Bi₂MoO₆ sensor was tested for 10–100 ppm ethanol. A high response of 82% was noted for 100 ppm ethanol concentration at 275 °C. The dynamic resistance response, selectivity, and sensor's stability were tested and analysed.