Composite titanate cathode enhanced with in situ grown nickel nanocatalyst for direct steam electrolysis

Abstract

This paper investigates the reversible exsolution of a Ni nanocatalyst anchored on the surface of La_0.3Sr_0.7TiO_3−δ (LSTO) for enhancing the electrocatalytic activity of the composite cathode. The metallic Ni nanoparticles significantly enhance the electrode performance and elevate the current efficiency of the electrode in high-temperature steam electrolysis. The combination of XRD, SEM, EDS and XPS results confirms that the exsolution and dissolution of the Ni nanoparticles are completely reversible in redox cycles. The electrical conductivities of the Ni-loaded samples accordingly improved as well. The synergetic effects of the Ni nanocatalyst and redox-stable titanate contribute to the excellent stability and improved performance for direct steam electrolysis. The current efficiencies with Ni-anchored LSTO can be accordingly enhanced by 20% in contrast to the bare cathode with or without reducing gas flowing over the cathode under the applied voltage of 2.0 V at 800 °C.