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

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.