An Sufeng,Wang Peng,Wang Kuanling,Wang Xuehai,Li Baozhong,Guo Xinwen
The M/SSZ-39 catalysts (M = In, Co, Cu, Fe) with different metal species and metal loadings were synthesized using the wet impregnation method on a small-pore SSZ-39 molecular sieve. X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-dehydrogenation and hydrogen temperature program reduction (H2-TPR) were employed to characterize the effects of various metal components and metal loadings on the performance of CH4 selective catalytic reduction of NO reaction (CH4-SCR). The characterization results showed that the In/SSZ-39 catalyst exhibited significantly higher catalytic activity compared to the Cu-, Co-, and Fe/SSZ-39 catalysts, suggesting that indium (In) is a more suitable active ingredient for the CH4-SCR reaction. The xIn/SSZ-39 (x = 1, 2, 3, x represents the In loadings of 1.0 wt%, 2.0 wt% and 3.0 wt%) catalysts, with different In loadings, all present excellent CH4-SCR performance. By varying the In loadings, the type of In species present in the catalyst can be regulated, thus enhancing DeNOx activity and CH4 selectivity in the CH4-SCR reaction. At a low temperature of 400 °C and a low CH4/NO feed ratio (CH4/NO = 1), the 3In/SSZ-39 catalyst, featuring highly active InOx clusters, achieves the best low-temperature CH4-SCR performance, with a high NO conversion rate of up to 90% and a CH4 selectivity of up to 74.2%.
Jiuhu Zhao,Huiying Li,Yungang Wang,Rongshu Zhu,Senlin Sun,Jingwen Zhang,Chaolin Li,Mei Hong
Mesoporous In/Hβ-X series catalysts were prepared by desilication method with tetrapropylammonium hydroxide (TPAOH) and indium incorporation for selective catalytic reduction of NO with methane (CH 4 -SCR). The post desilication treatment conditions for preparing In/Hβ-X were optimized. Etching time is the most important desilication parameter influencing the resulting CH 4 -SCR performance of the catalyst. The In/Hβ-3 sample which was etched for 3 h presents the highest NO x conversion, 22% higher than In/H-Beta counterparts using commercial microporous beta. Obvious analysis reveals that besides generating mesopores, controlled desilication can modulate the proportion of InO + active sites and surface oxygen species, allowing more active sites to be exposed.
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