A redox-stable chromate cathode decorated with in situ grown nickel nanocatalyst for efficient carbon dioxide electrolysis

Abstract

The redox-stable La_0.75Sr_0.25Cr_0.5Mn_0.5O_3−δ (LSCM) ceramic can be utilized as a solid oxide electrolyzer cathode for direct carbon dioxide electrolysis; nevertheless, the insufficient electro-catalytic activity of ceramic LSCM restricts the electrode performance and current efficiency. In this paper, catalytically active nickel nanoparticles are anchored on the surface of an LSCM substrate through an in situ growth process to improve the electrode performance. The combination of XRD, TEM, XPS, SEM and EDS analyses demonstrate the reversible in situ growth of the nickel catalyst by transforming A-site deficient and B-site rich (La_0.75Sr_0.25)_0.9(Cr_0.5Mn_0.5)_0.9Ni_0.1O_3−δ (LSCMN) into LSCM and nickel in redox cycles. The conductivities of LSCM and LSCMN are investigated and correlated with electrode performance in symmetrical cells and electrolysis cells. A significant improvement in electrode polarization resistance is observed for the LSCMN cathode. The current efficiency is considerably improved by 30% for LSCMN in contrast to the bare LSCM cathode for direct carbon dioxide electrolysis at 800 °C.