Design and internal structure analysis of submicron aggregated and porous three-way catalyst particles synthesized...

The development of efficient three-way catalysts (TWCs) is crucial for reducing vehicle emissions and addressing environmental concerns. However, the widespread application of TWCs is limited by their reliance on expensive precious metals and challenges in optimizing catalytic performance at low temperatures. To address these limitations, this study presents a novel approach to designing and characterizing submicron spherical aggregated TWC particles and porous structured TWC particles, which were synthesized using a spray drying method. The objectives of this research focus on optimizing the particle size of aggregated TWC particles, analyzing the internal porous architecture of porous TWC particles, and evaluating their catalytic performance in CO conversion. The synthesis process allowed precise control over the particle size of aggregated TWC particles by adjusting the concentration of colloidal TWC nanoparticles, revealing that smaller aggregated particles (520 nm) exhibited superior CO conversion efficiency compared to larger particles (1,180 nm) due to enhanced gas accessibility. Cross-sectional and three-dimensional elemental mapping analyses of porous TWC particles provided insights into the homogeneity of elemental distribution and interconnected pore networks, critical for efficient gas transport. Furthermore, the effect of CO gas flow rate on catalytic performance was systematically investigated, demonstrating that lower gas flow rates enhanced CO conversion efficiency at reduced temperatures due to prolonged gas-catalyst contact time. This work demonstrates a clear correlation between particle size of aggregated TWC particles and their catalytic efficiency, as well as highlights the influence of gas flow rates on the catalytic activity of porous TWC particles.