Sol‐Gel Preparation of Perovskite Oxides Using Ethylene Glycol and Alcohol Mixture as Complexant and Its Catalytic Performances for CO Oxidation

Abstract

We reported an updated sol‐gel method for the preparation of perovskite oxide using ethylene glycol and alcohol mixture as complexant. Relative to that prepared by sol‐gel method using citric acid as complexant, the sample prepared by this updated method showed porous structure, higher surface area, more oxygen vacancies and stronger reducibility, due to a two‐step combustion process. By comparing the phase transformation temperature of perovskite oxides using different transition metals, it was inferred that the electron distribution in the 3d orbit is a crucial factor influencing the formation of perovskite structure. The easier the electrons to be excited, the easier the perovskite structure to be formed. Catalytic results showed that the sample (e. g., LaCoO3‐EM) prepared by the updated method is more active for CO oxidation than that prepared by citric acid method, with full CO conversion obtained at 135 °C and no activity loss is observable either by long‐term (30 h) or by cycling (3 times) stability tests. Effect of the chain length of alcohols on the properties of LaCoO3 was also studied.

Perovskite Oxides: Syntheses and Perspectives on Their Application for Nitrate Reduction

“… Schematic representation of sol–gel synthesis method for LaCoO 3 perovskite oxide. 75 Reprinted with permission from ref ( 75 ). Copyright 2018 John Wiley & Sons Ltd. …”

LaMnxCo1‐xO3 (x=0, 0.25) Perovskites: Novel Nano Catalysts for Removal of Thiophene compounds in Fuels by Catalytic and Ultrasound‐assisted Oxidative Desulfurization

“…Different types of catalysts have been investigated in the UAOD process [19a,b,c] . One of the catalysts that show the high activity of oxidation processes [16c,d,20–22] but have not been studied in the desulfurization process is Perovskite type oxides. They mixed metal oxides with the general formula of ABO 3 .…”

“…However, lanthanide elements are expensive to some extent but play a crucible role in the catalytic activity and stability of perovskites. The element in B‐site in the perovskite structure determined the catalytic activity and usually in the stable and active perovskites, the transition metals such as Mn and Co occupy the B‐sites [16c,d,23–25] . So, in this work, LaCoO 3 and LaMn 0.25 Co 0.75 O 3 perovskites were synthesized and developed as novel nanocatalysts for catalytic oxidative desulfurization (CODS) processes.…”

“…They mixed metal oxides with the general formula of ABO 3 . In these compounds, the cation in A‐site is usually an element in lanthanide series such as La, Ce and Sm [16c,d,23–25] . However, lanthanide elements are expensive to some extent but play a crucible role in the catalytic activity and stability of perovskites.…”