Physicochemical Properties of MnO₂Catalyst Prepared via Hydrothermal Process and its Application for CO Oxidation

Abstract

주제어 : 이산화망간, CO 산화반응, 수열합성, 결정구조 Abstract : MnO2 was prepared by a hydrothermal process method in the range of 120-200 ℃ and 0.5-5 h, calcined at 300 ℃ after induction of precipitation using KMnO4 and MnCl2･4H2O, and its catalytic activity was compared for CO oxidation. The catalysts were characterized using by X-ray diffraction, N2-sorption, scanning electron microscopy, and temperature programmed reduction of H2 or CO. The crystalline structure of pure α-MnO2 or hybrid α/β-MnO2 was controlled by the preparation conditions. The pure α-MnO2 showed better catalytic activity and thermal stability than hybrid α/β-MnO2. Especially, α-MnO2 prepared at 150 ℃ for 1 h has the highest specific surface area 214 m 2 g -1, reducibility and labile lattice oxygen species analyzed by H2, CO-TPR, respectively. It also showed the best CO oxidation activity in both conditions of temperature programmed and isothermal reaction. The results came from the physicochemical properties of catalysts like the crystalline structure, specific surface area, reducibility and lattice oxygen species, and which are correlated with catalytic performance.