Boosting the low-temperature NH3-SCR performance via metals co-doping with inequality Mn/Ce ratios in the carbon-based catalyst prepared by Cr-containing leather waste

Abstract

The resource utilization of Cr-containing leather waste is still a great challenge. In this work, waste from leather production as raw material was attempted to be used to synthesize activated carbon, a series of MnxCe1-xZr0.5/AC composite catalysts were prepared via loading three metal elements onto activated carbon by impregnation method, the NH3-SCR performance was measured in a low temperature range of 50 ∼ 200 °C. Among them, the catalyst Mn0.7Ce0.3Zr0.5/AC displays the optimal low-temperature SCR activity, excellent resistance to GHSV, H2O and SO2. The characterization results indicated that increasing the Mn/Ce inequality ratios within a certain range would promote the electron transfer between the active metal components, thereby enhancing the synergistic effect and the redox capacity of the catalysts, and it also could significantly improve the concentration of Lewis acid sites to accelerate the adsorption and activation of NH3, resulting in different catalytic activities. The in situ DRIFTS results prove that the Lewis acid site plays a vital role in the “fast SCR” reaction, and the whole reaction process conforms to the Langmuir-Hinshelwood (L-H) mechanism.