Synthesis of palygorskite-supported Mn1−xCexO2 clusters and their performance in catalytic oxidation of formaldehyde

Abstract

Abstract Nano-scale Mn 1 − x Ce x O 2 catalysts supported on palygorskite (PG) with different dopant fractions were prepared by the co-precipitation method and applied in the catalytic oxidation of formaldehyde (HCHO). The obtained samples were characterized using BET, XRD, Raman spectroscopy, TEM, EDS, and H 2 -TPR to illustrate the physicochemical properties of the catalysts. After the introduction of cerium, the growth of manganese oxide was inhibited. However, an increase of the Ce/(Ce + Mn) ratio from 0.1 to 0.5 increased the particle size from 2.87 to 6.86 nm. A remarkable interface (grain boundaries) between MnO 2 and CeO 2 was observed, especially for low cerium molar fractions (0.1–0.4). The doping of cerium significantly enhanced the activity of manganese oxide for HCHO oxidation at 100–180 °C. The Mn 0.9 Ce 0.1 /PG catalyst exhibited the best activity, and HCHO was completely converted to CO 2 and H 2 O at 160 °C. The characterization results indicated that smaller particle size, surface-adsorbed oxygen species and abundant oxygen vacancies accounted for the high catalytic activity of the Mn 0.9 Ce 0.1 /PG catalyst for HCHO conversion. In addition, the Mn 0.9 Ce 0.1 /PG catalyst also displayed high stability in lifetime testing and excellent water-resistant performance. The experimental results suggest that palygorskite-supported Mn 0.9 Ce 0.1 is a promising catalyst for the catalytic oxidation of formaldehyde at low temperatures.