The structure–activity relationships of Rh/CeO2–ZrO2 catalysts based on Rh metal size effect in the three-way catalytic reactions
Dongming Chen, Weixin Zhao, Zihao Xu, Zheng Zhao, Juanyu Yang, Yongke Hou, Yongqi Zhang, Zongyu Feng, Meisheng Cui, Xiaowei Huang
Abstract
With the continuous tightening of automotive emission regulations and the increasing promotion of energy-efficient hybrid vehicles, new challenges have arisen for the low-temperature performance of three-way catalysts (TWCs). To guide the design of next-generation TWCs, it is essential to further develop our understanding of the relationships between microstructure and catalytic performance. Here, Rh/CeO 2 –ZrO 2 catalysts were synthesized with different Rh metal dispersion by using a combination of the wet impregnation method and reduction treatment. These catalysts included Rh single-atom catalysts, cluster catalysts, and nanoparticle catalysts. The results showed that the Rh nanoparticle catalyst, with an average size of 1.9 nm, exhibited superior three-way catalytic performance compared to the other catalysts. Based on the catalytic activity in a series of simple reaction atmospheres such as CO + O 2 , NO + CO, and hydrocarbons (HCs) + O 2 and operando infrared spectroscopy, we found that metallic Rh sites on Rh nanoparticles are the key factor responsible for the low-temperature catalytic performance.