Low temperature CO oxidation by doped cerium oxide electrospun fibers

Tae-Sik Oh,Myeongseok Sim,Buhua Wang

doi:10.1186/s40580-020-00234-7

Abstract

We investigated CO oxidation behavior of doped cerium oxide fibers. Electrospinning technique was used to fabricate the inorganic fibers after burning off polymer component at 600 °C in air. Cu, Ni, Co, Mn, Fe, and La were doped at 10 and 30 mol% by dissolving metal salts into the polymeric electrospinning solution. 10 mol% Cu-doped ceria fiber showed excellent catalytic activity for low temperature CO oxidation with 50% CO conversion at just 52 °C. This 10 mol% Cu-doped sample showed unexpected regeneration behavior under simple ambient air annealing at 400 °C. From the CO oxidation behavior of the 12 samples, we conclude that absolute oxygen vacancy concentration estimated by Raman spectroscopy is not a good indicator for low temperature CO oxidation catalysts unless extra care is taken such that the Raman signal reflects oxide surface status. The experimental trend over the six dopants showed limited agreement with theoretically calculated oxygen vacancy formation energy in the literature.

Highlights

CO oxidation is a representative model oxidation reaction in heterogeneous catalysis [1]
4 Conclusion We demonstrated low temperature CO oxidation using metal-free electrospun ceria catalyst with a variety of dopants
Even with high processing temperature to burn off polymeric constituent, the resulting ceria catalyst was still effective in low temperature CO oxidation

Summary

Introduction

CO oxidation is a representative model oxidation reaction in heterogeneous catalysis [1]. In addition to lowering energy cost by low temperature operation, catalysts free from precious metals are attractive due to low materials cost. Cerium oxide is an interesting material that has shown synergistic impact with metallic nanoparticles for volatile organic compound oxidation [13, 14]. Cerium oxide is a well-known oxygen storage material that is used in three-way catalytic converters and solid oxide fuel cell fuel electrodes [15,16,17,18,19,20]. Ceria-based nanofibers were synthesized using the electrospinning technique to investigate their catalytic activity toward CO oxidation. To study the effects of dopants, Cu, Ni, Co, Mn, Fe, and La were doped at 10 and 30 mol% by dissolving metal salts into the polymeric electrospinning solution. This work demonstrates the potential of electrospun selfsupported cerium oxide catalyst for CO oxidation

Experimental

Results and discussion

Conclusion