Effect of surface morphology on catalytic activity for NO oxidation of SmMn2O5 nanocrystals

Abstract

SmMn2O5 has been reported to be a promising alternative to substitute the current commercial Pt-based catalysts for NO oxidation. In this work, single-crystalline orthorhombic SmMn2O5 nanorods and nanoparticles are successfully synthesized through a tunable hydrothermal route. The pH value of the precursor solution is a decisive factor for morphology control of SmMn2O5 nanocrystals, with decreasing pH value the morphology of SmMn2O5 nanocrystals converts from nanoparticles to nanorods. The nanoparticles exhibit a better catalytic activity for NO oxidation than the nanorods, because they can efficiently convert NO at lower temperature. By the analysis of X-ray photoelectron spectrum and high-resolution transmission electron microscope, the oxidation activity is found to be dependent on the high specific surface area and surface crystal planes of SmMn2O5 nanocrystals, which widens and deepens the oxygen chemistry and NO oxidation mechanism on the surfaces of SmMn2O5. This work could not only provide new insights into the morphology control of SmMn2O5 nanocrystals, but also pave a new way for the crystal planes modification of SmMn2O5 nanocrystals as NO oxidation catalyst to achieve an enhanced performance for environmental applications.