Deterioration mechanism of selective catalytic oxidation of NH3 to N2 over CeZrO4 by incorporation of alkali metals and calcium

Highly Efficient RuOx/NbOx-ZrOx Catalysts for Ammonia Removal via Tuning Acidic Active Species

“…Note that a new peak of amide (−NH 2 ) appeared at 1568 cm −1 starting from 100 °C. 79,85 At the same time, the peak at 1265 cm −1 was red-shifted and a peak associated with −NH 2 also appeared at 1250 cm −1 . 75,86 The intensity of these peaks progressively increased in 100−200 °C and subsequently decreased after 200 °C.…”

“…This illustrated that for R/Z, the ammonia adsorption on the Lewis acid site was more stable than on the Bro̷nsted acid site. Note that a new peak of amide (−NH 2 ) appeared at 1568 cm –1 starting from 100 °C. , At the same time, the peak at 1265 cm –1 was red-shifted and a peak associated with −NH 2 also appeared at 1250 cm –1 . , The intensity of these peaks progressively increased in 100–200 °C and subsequently decreased after 200 °C. This might be due to the activation of NH 3 species adsorbed on Lewis and Bro̷nsted acid sites below 200 °C, which dissociates H and thus generated −NH 2 intermediate species (eq ).…”