Enhanced low-temperature activity of Rh-Pt alloy clusters supported on TiO2/Ti nanosheets for selective catalytic reduction of NO by CO

Achieving high catalytic activity at low temperatures in the selective catalytic reduction of NO by CO (CO-SCR) remains a significant challenge, primarily due to the inhibitory effect of O₂, which hampers the NO reduction process. In this study, we designed Rh-Pt alloy clusters supported on TiO₂ nanosheets to optimize the CO-SCR performance. Among the catalysts investigated, Rh1Pt1/TiO₂/Ti demonstrated exceptional low-temperature catalytic performance. Under 0.15 % O₂ conditions, the Rh1Pt1/TiO₂/Ti catalyst achieved complete NO conversion at 180 °C, outperforming both Rh1/TiO₂/Ti and Pt1/TiO₂/Ti catalysts. Characterization results revealed the strong interaction between Rh, Pt and TiO₂ optimizes electron transfer, enhances overall catalytic activity and promotes efficient adsorption and activation of both CO and NO. Specifically, Rh facilitates the adsorption and dissociation of NO, while Pt enhances CO adsorption and transformation. Based on in-situ FTIR experiments and DFT calculations, a possible reaction mechanism for the Rh-Pt/TiO₂/Ti catalyst in CO-SCR was proposed. This study provides valuable insights for the exploration and development of CO-SCR catalysts towards industrial application.