Determining influence of catalyst-reductant morphology on two different mechanisms of SCR by MOFs

The micro-morphology of catalyst played an important role in the selective catalytic reduction of nitrogen oxide. For the first time, this work investigated the relationship among catalytic activity, catalyst–catalyst distance, and catalyst–reductant distance. Three metal–organic frameworks with different morphologies were applied in the catalysis. When catalyst–catalyst distance was decreased from 3.436 to 2.890 A, the activity was increased from 59.5 to 92.3% at 250 °C. Even without ammonia reductant, when catalyst–reductant distance was decreased from 3.033 to 2.620 A, the activity was increased from 7.5 to 78.1% at 350 °C. In this case, organic/carbon played as the reductant. Moreover, the relationship successfully predicted the activity of a catalyst with a known catalyst–reductant​ distance. A shorter catalyst–catalyst and catalyst–reductant​ distances facilitated electron and material transfers between reductant and nitric oxide, thus increasing the activity. After all, main results of this work helped to understand the interaction on interface between catalyst and reductant, which was in favor of catalyst design and application.