Synergistic Catalysis of Rh Single-Atom and Clusters Supported on TiO2 Nanosheet Array for Highly Efficient Removal of CO and NOx

Abstract

Developing an efficient catalyst is the key to selective catalytic reduction (SCR) of NO_x by CO (CO-SCR) to simultaneously address the pollution of toxic NO_x and CO. Herein, a novel Rh/TiO₂/Ti monolithic catalyst is designed and synthesized, featuring Rh species in the form of single atoms (Rh₁) and clusters (Rh_n). This catalyst overcomes the inhibitory effects of oxygen, achieving low-temperature NO conversion. The investigation substantively contributes insights into the strategic manipulation of active metal components, emphasizing the potential of single-atom/cluster catalysts to enhance efficiency. The Rh/TiO₂/Ti catalyst has demonstrated exceptional catalytic efficacy, achieving 100% NO conversion at a low temperature of 190 °C in the presence of oxygen. Additionally, it exhibits remarkable stability and water resistance for practical applications. Moreover, comprehensive characterization confirms that Rh clusters and single-atom sites play an important role in the selective adsorption of NO and CO molecules, promoting the formation of –N₂O species and ultimately resulting in the complete conversion of NO and CO to N₂ and CO₂. This study not only provides valuable guidance for designing high-performance CO-SCR catalysts but also underscores the potential of single atoms/clusters catalytic systems in both fundamental research and industrial catalysis.