Chemically driven BaTiO3–CoFe2O4 nanocomposite with strong dielectric and low leakagecharacteristics for electrocatalytic water splitting reaction.

The switchable electronic properties at the surface of ferroelectric nanomaterials offer possibilities for electrocatalytic hydrogen and oxygen evolution reactions, HER and OER respectively. Here, 0.5(BaTiO 3)-0.5(CoFe 2 O 4) (abbreviated as BTCF0.5) are prepared chemically. The material shows a high dielectric constant in the order of 107. Nyquist plot is consistent with non-Debye-type and negative temperature coefficient of resistance (NTCR) characteristics with low leakage current. BTCF0.5 shows superior electrocatalytic HER and OER with a low overpotential of ∼156 and ∼284 mV at current density10 mA/cm2 along with Tafel slopes of 43.37 mV/dec and 41.52 mV/dec respectively. The stability of the electrocatalyst is checked through a chronoamperometry test and up to 1000 cycles of CV both for HER and OER operations. The non-traditional behavior of the nanocomposite may make it highly desirable for usage in numerous renewable and sustainable energy-related applications in the present-day scenario. [Display omitted] • 0.5BaTiO 3 -0.5CoFe 2 O 4 nanocomposite sample was synthesized by chemical route. • A high dielectric constant in the order of 104 - 107 was observed at room temperature. • An impedance study was performed which confirmed the non-Debye type relaxation. • HER, OER showed 156 mV and 284 mV overpotential at 10 mA cm−2 current density. • The electrocatalyst showed ∼1.65 V cell voltage for overall water splitting. [ABSTRACT FROM AUTHOR]