Structural effects of LaNiO3 as electrocatalyst for the oxygen reduction reaction

Abstract

LaNiO perovskite is a promising electrocatalyst for the oxygen reduction reaction (ORR). In this work we study the effects of several key structural and morphological features on the performance of LaNiO perovskites for the ORR. We have prepared a series of LaNiO oxides via soft chemistry and calcined the final materials at different temperatures from 500 to 1000 °C. With the aim of obtaining morphological and structural information relevant to their performance the prepared oxides have been thoroughly characterized by BET, Power Neutron Diffraction (PND), XRD, HRTEM, STEM-HAADF and XPS. We have analysed the effect of extrinsic (surface area and particle size) and intrinsic factors (formation of oxygen vacancies, Ni oxidation states and occupancy of the e levels) on the current densities and specific activity, respectively, of several samples of LaNiO. The catalysts with higher catalytic activity are those in which the perovskite structure is properly formed, but display high surface areas.