Enhanced catalytic combustion of complex VOCs over Ru/Ni-HAP catalyst: Insights into the synergic effects of Ru and Ni species

In this study, Ni was severed as a promoter and impregnated on hydroxyapatite (HAP) to prepare a Ni-doped HAP support, and then Ru was highly dispersed onto the Ni-HAP through urea precipitation method. The synergistic effects between Ru and Ni caused a reduction in the particle size of Ru nanoparticles and an increased Ru⁴⁺/Ru⁰ ratios, which was primarily attributed to the strong interaction between the active components and functional groups of OH^- and PO₄^3-. Meanwhile, Ru/Ni-HAP possessed the highest amount of medium-strength acid sites and relatively low reduction temperatures, indicating the critical balance between acidity and redox capability. Ru/Ni-HAP exhibited superior activity with complete conversion of toluene at 280 °C and DCM at 400 °C, respectively, and such high activity can be maintained throughout the stability tests. Besides, optimal catalytic performance was observed under 600 ppm concentrations of toluene and DCM with a space velocity of 40,000 mL(g·h)^-1. These findings can provide valuable insights for the development of chlorine-resistant catalysts with promising application prospects.