Flame synthesized nanoscale catalyst (CuCeWTi) with excellent Hg⁰ oxidation activity and hydrothermal resistance

In view of poor hydrothermal resistance of impregnation prepared catalysts (Cu5Ce5W9Ti-I), this paper aims to enhance thermal and hydrothermal resistance of Cu/Ce based catalysts for Hg⁰ oxidation via flame synthesis technology. The result found that the flame synthesis method could form nanoscale Cu10Ce10W9Ti-F particles with smaller lattice size (8-25 nm), more stable carrier structure and more oxygen vacancies. The inter-doping and inter-substitution of Ce, Cu and Ti oxides created more oxygen vacancies (Ce³⁺) and L-sites (O^2-). Furthermore, the carrier TiO₂ of Cu10Ce10W9Ti-F existed in form of highly thermostable rutile rather than anatase. High Hg⁰ oxidation efficiency (MOE) of 83.9-99.7% at 100-450 °C proved excellent oxidation activity of Cu10Ce10W9Ti-F catalyst. Moreover, the thermal and hydrothermal treatment (700 °C) only decreased MOE by less than 5% since L-sites kept fine thermostability of Cu10Ce10W9Ti-F. The flame synthesis was proven to be a promising catalyst preparation method to enhance thermal and hydrothermal resistance.