Low-temperature catalytic combustion of benzene over Zr–Mn mixed oxides synthesized by redox-precipitation method

Abstract

Zr-Mn mixed oxides with various Zr/Mn molar ratios were synthesized by redox-precipitation method and applied to benzene catalytic combustion. The results showed that the addition of Zr to MnO2 could improve the benzene combustion activity, among which Zr/MnO2-0.2 catalyst performed the best catalytic activity with T50 and T90 of 171 °C and 195 °C (1000 ppm benzene, GHSV = 60,000 ml · g−1 · h−1, 0% RH (relative humidity), 20 vol% O2/N2), respectively. A series of characterizations were used to investigate the structure–activity relationship of Zr–Mn mixed oxides, which demonstrated that the larger specific surface area, more surface reactive oxygen species, higher low-temperature reduction and acidity contributed to the enhanced catalytic activity of Zr–Mn mixed oxides. Finally, the possible pathways of benzene combustion over Zr–Mn mixed oxides were explored by in-situ DRIFTS spectra and the possible intermediates generated under different conditions were also revealed.