An efficient strategy to screen an effective catalyst for NOx-SCR by deducing surface species using DRIFTS

Abstract

Hypothesis: Transition metal supported TiO₂ is one of the hottest catalysts in the field of selective catalytic reduction (SCR) of nitrogen oxides. Various formulas have been put forward for an enhanced activity. However, seldom work emphasizes on easy and fast screening of an effective catalyst.

Experiments: In this work, Diffuse Reflection Fourier Transform Infrared (DRIFTS) screened catalyst by analyzing intermediates during SCR.

Findings: TiO₂ provided main adsorption sites for NH₃ and the "Eley-Rideal" mechanism dominated the catalysis. The transition metals served as the bridge of electron transport. Moreover, the area reduction rate of adsorbed NH₃ and NH₄⁺ species in DRIFTS represented the electron-transfer rate as well as catalytic activity. In other words, a faster area reduction indicated a better SCR activity. Therefore, this work supplied a fast strategy to screen the most effective catalyst among different materials even without using a nitrogen oxides detector. At the same time, less ammonia and nitrogen oxides were used or discharged.

Keywords: DRIFTS; Screening; Selective catalytic reduction; TiO(2); Transition metal.