Engineering Macroporous Structure Towards Enhancing Mass Transfer and Catalytic Performance of Three-Way Catalyst Particles

The increasing emission of pollutants from gasoline-power vehicles has prompted concerns regarding human health and the environment. To address this issue, researchers have focused on developing novel technologies to mitigate their adverse effects, and a three-way catalyst (TWC) has emerged as a crucial technique in this area since the 1970s. However, the TWC materials are composed of large amounts of costly and rare elements, including Rhodium (Rh), Palladium (Pd), and Platinum (Pt), which considerably increases their manufacturing expenses. Consequently, it is necessary to reduce the consumption of TWCs as their demand increases due to the global outbreak of transportation vehicles over the years. The promising method to overcome this challenge is to enhance their catalytic performance by appending the porous structure. Catalyst particles endowed with macroporous architectures have gained considerable attention due to their superior molecular diffusion capabilities and catalytic activities.<br/>In this study, the macroporous TWC particles with interconnected macropore networks were synthesized via a template-assisted spray process. The synthesis of macroporous TWC particles requires precise control over various parameters. Furthermore, the mass transfer coefficients of the macroporous TWC particles were then investigated by measuring the CO₂ adsorption rate, allowing us to understand the influence of macroporous structure on internal mass transfer. The results demonstrate a significant enhancement in the mass transfer coefficient upon introducing macropores into the TWC particles compared to conventional aggregate TWC particles. However, a decline in the mass transfer coefficient was observed as the macropore size exceeded a certain threshold due to the presence of an extensive framework. To explore the practical implications of these macroporous TWC particles in the catalysis field, we conducted catalytic performance assessments using CO oxidation reaction as the model. Remarkably, the macroporous samples exhibited superior catalytic performance compared to their aggregate counterparts. These results demonstrate the critical role of macroporous structure in enhancing the catalytic performance of TWC particles.<br/>In conclusion, our comprehensive study highlights the significance of macroporous structures in catalyst particles and their potential to revolutionize TWC efficiency. The profound improvements in mass transfer coefficients and catalytic performance provide valuable insights for designing advanced TWC materials that exhibit enhanced pollutant conversion capabilities.