Selective catalytic reduction of NOx with NH3 on Mn, Co-BTC-derived catalysts: Influence of thermal treatment temperature

Abstract

The paper presented facile method for preparing Mn, Co-BTC (BTC ​= ​1,3,5-benzenetricarboxylic acid) derived catalyst with honeycomb structure through direct decomposition of Mn and Co based metal-organic framework (MOF) Mn, Co-BTC in air. Also, the correlation between catalytic performance of MOF (metal organic framework) derivatives for the selective catalytic reduction (SCR) of NOx with ammonia and annealing temperature have been investigated. The catalytic activity test results indicated that annealing temperature had the clear promoting effects on catalytic performance. The X-ray photoelectron spectroscopic (XPS), X-ray diffraction (XRD), Thermogravimetric (TG), Scanning electron microscopy (SEM), Temperature programmed reduction of H2 (H2-TPR) and Fourier-transform infrared (FTIR) spectra were employed to characterize Mn, Co-BTC and its derived catalysts. Based on SEM, FTIR and XRD analytical results, Mn, Co-BTC with nanoneedle structure turned into (Co, Mn) (Co, Mn)2O4 spinel compound with honeycomb structure accompanied by decomposition of organic linkers through direct annealing process. The XPS and H2-TPR results showed that Mn, Co-BTC-500 (Mn, Co-BTC annealed at 500 ​°C) had the greatest interaction between Mn and Co, resulting in high catalytic performance for NH3-SCR of NOx, which were consistent with catalytic performance test results. Finally, based on the in-situ DRIFT experiments, it was suggested that the SCR process of NOx with NH3 over Mn, Co-BTC-500 followed both Langmuir–Hinshelwood (L–H) mechanism and Eley-Rideal (E-R) mechanism.