Controlling Chelation and Esterification in Pechini Synthesis for Enhancing Chemical Looping Steam Methane Reforming Using LaFeO <sub>3</sub> Perovskite
Yikyeom Kim, Eui-Chul Jeong, Hyeon Seok Kim, Jae Wook Lee
Abstract
Abstract The properties of an oxygen carrier, such as crystalline structure, textural properties, and surface chemical species, significantly influence the redox performance in thermochemical redox applications. This study presents the synthesis of various lanthanum orthoferrite (LaFeO 3 ) perovskites by adjusting Pechini synthesis parameters, including chelating agent ratio, calcination temperature, and solution pH. A larger surface area emerged as a dominant factor contributing to improved redox performance. The porosity of the polyester resin proves crucial in achieving a large surface area and a small particle size for the oxygen carrier. This goal could be attained by controlling the pH of the precursor solution. A low degree of chelation or precipitation may lead to uneven cation distribution, resulting in the enrichment of trace hydroxide impurities. These impurities can suppress the reducibility of particles during the looping experiment. Various investigations, using XRD, XPS, XAS, SEM, and N 2 physisorption, revealed that porosity and crystallinity can be controlled by altering the synthesis parameters.