Formic Acid Modified Co3O4-CeO2 Catalysts for CO Oxidation

Ruishu Shang,Wei Xie,Yiping Duan,Lihong Huang,Yan Luo,Xinyan Zhong

doi:10.3390/catal6030048

Abstract

A formic acid modified catalyst, Co3O4-CeO2, was prepared via facile urea-hydrothermal method and applied in CO oxidation. The Co3O4-CeO2-0.5 catalyst, treated by formic acid at 0.5 mol/L, performed better in CO oxidation with T50 obtained at 69.5 °C and T100 obtained at 150 °C, respectively. The characterization results indicate that after treating with formic acid, there is a more porous structure within the Co3O4-CeO2 catalyst; meanwhile, despite of the slightly decreased content of Co, there are more adsorption sites exposed by acid treatment, as suggested by CO-TPD and H2-TPD, which explains the improvement of catalytic performance.

Highlights

Removal of CO has been studied extensively because CO is toxic and poses health concerns in fields of exhaust emission control and air purifications
For the catalyst of Co3 O4 -CeO2, the surface area increased to 53.0 m2 /g; the results of CO-Temperature-Programmed Desorption (TPD) indicate that the capacity for CO adsorption was increased, suggesting that there were more active sites consisting of Co and CeO2 with redox capacity for CO and O2 activation
With formic acid treatment at 0.5 mol/L for the Co3 O4 -CeO2 -0.5 catalyst, because of the dissolving of Co species, the composite structure became more porous with a higher surface area and pore volume, as indicated by N2 physisorption; despite the decreased content of Co, the CO adsorption capacity was increased, suggesting that there could be more active sites exposed by acid treatment, as indicated by CO-temperature-programmed desorption (CO-TPD) and H2 -TPD

Summary

Introduction

Removal of CO has been studied extensively because CO is toxic and poses health concerns in fields of exhaust emission control and air purifications. Low temperature oxidation of carbon monoxide is considered to be the most efficient and cost-effective method for removal of CO [1,2]. For CO oxidation at low temperature, catalyst with high activity is a key factor. Noble metal catalysts, such as Pt, Ru, Rh, Au, etc., show high activity and stability in CO oxidation [2]. The high cost of noble materials is a concern. Transition metal oxides and their mixed oxides have been studied for CO oxidation, such as MnOx and CuO-CeO2 [3,4]

Results

Discussion

Conclusion