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

Nano-scale Mn1 − xCexO2 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 H2-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 MnO2 and CeO2 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 Mn0.9Ce0.1/PG catalyst exhibited the best activity, and HCHO was completely converted to CO2 and H2O 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 Mn0.9Ce0.1/PG catalyst for HCHO conversion. In addition, the Mn0.9Ce0.1/PG catalyst also displayed high stability in lifetime testing and excellent water-resistant performance. The experimental results suggest that palygorskite-supported Mn0.9Ce0.1 is a promising catalyst for the catalytic oxidation of formaldehyde at low temperatures.