Hydrothermal tolerance towards different temperature conditions over two typical Cu/CHA catalysts

Understanding the Water Effect for Selective Catalytic Reduction of NOx with NH3 over Cu-SSZ-13 Catalysts

“…Generally, detrimental effects on Cu-SSZ-13 catalysts were consistently observed in the presence of water with high-temperature treatment. It would lead to degradation of the zeolite support structure, conversions of [Cu­(OH)] + to CuO x clusters, loss of acid sites, and affected diffusion and adsorption of different reactants. − In addition, an inhibitory effect of water vapor to the reduction half-cycle from Cu II to Cu I was also detected, which hindered the NH 3 -SCR performance of Cu-SSZ-13 in a low-temperature regime . It was also observed that one major category of copper chabazite catalysts, Cu-SAPO-34, was probably susceptible to water vapor deactivation with massive hydrolysis of the framework. , The low-temperature hydrolysis would cause isolated Cu to detach and form Cu­(OH) 2 , further with terminal Al to generate inactive complexes .…”