MnOx fabrication with rational design of morphology for enhanced activity in NO oxidation and SO2 resistance

This paper synthesized MnOx based catalysts with rational design of morphology to investigate the improvement in NO oxidation and SO2 resistance. SEM and TEM characterizations illustrated the fabrication of hollow morphology and irregular rod-like morphology. Significant enhancement in NO oxidation by O-2 was attained comparing with MnO2-C, especially at low temperature. Ce and Fe were selected as the second metal to modify H-MnO2 and MnO2-R catalysts. Notably, H-MnFeO2 equipped with rambutan-like morphology, further improved NO conversion, i.e., 89.8% at 220 degrees C (84.0% for H-MnO2). These catalysts with rational design of morphology displayed high BET surface area that was larger than 100 m(2)/g. For SO2 resistance, H-MnO2 exhibited the best 20 ppm SO 2 tolerance and maintained its initial NO conversion within 360 min rather than deactivation immediately as MnO2-C. The Ce and Fe addition on MnO2-R moderately improved the SO2 resistance within the whole 480 min test. Overall, the hollow cavity structure of H-MnO2 could provide shuttle space for oxidation and improved mass adsorption and transformation, thereby attaining the better NO conversion and SO2 resistance. Finally, the mechanism for NO oxidation was proposed according to in-situ DRIFTS results.