Phase-separated Ce-Co-O catalysts for CO oxidation

As a major gas pollutant, the control of CO gas emission from chemical industry and vehicle exhausts has aroused global attention in the past years and it is extremely essential to develop efficient, low-cost and environmental friendly catalysts for CO conversion and removal. In this work, we report the facile synthesis of Ce-Co-O catalysts through a simple ultrasonic spray pyrolysis process and investigate their application for low-temperature CO oxidation. The Ce-Co-O catalysts comprising of separated CeO2 and Co3O4 phases show superior CO oxidation capability below 473 K (200 degrees C) without the assistance of any other co-catalyst or noble metal. With the increase of Co3O4 concentration, the CO oxidation temperature of Ce-Co-O catalysts decreases quickly and reaches a complete conversion temperature of 410 K (137 degrees C) in the case of the optimized Co content. Microstructure analysis using high-resolution transmission electron microscope reveals that the tiny CeO2 and Co3O4 phases assembled into porous particles are well crystallized and show high chemical purity. The porous feature of Ce-Co-O catalysts synthesized from feasible ultrasonic spray pyrolysis makes them more competitive and promising towards gaseous environmental pollution processing including CO oxidation, TWCs, SCR, etc. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.