Improved resistance to water poisoning of Pd/CeO2 monolithic catalysts by heat treatment for ozone decomposition

Abstract

Durability is a crucial requirement in heterogeneous catalysis; however, many catalysts suffer from severe deactivation in humid conditions due to water poisoning. Ozone, as a significant air pollutant, should be efficiently removed through catalytic decomposition, making it imperative to develop a water-tolerant monolithic catalyst for practical air purification. In this study, we present highly durable Pd/CeO2 monolithic catalysts resistant to water poisoning achieved through a simple heat treatment of the ceria support. The heat treatment controlled the ceria surface properties, including oxygen vacancy defects, surface oxygen, and basicity, thereby improving resistance to water poisoning. When Pd/CeO2 monolithic catalysts were used in bench-scale ozone decomposition under humid conditions, the catalyst heat-treated at 900 °C exhibited superior performance without experiencing deactivation due to water poisoning. Modulating the ceria surface properties plays a pivotal role in enhancing water resistance, and heat-treated Pd/CeO2 monolithic catalysts stand as a promising candidate for practical ozone decomposition in air purification applications.